62 ANATOMY FOK NURSES. [CHAP. VI.
The muscles of the back are disposed in five layers, one be-
neath another. The two largest and most superficial are the
trapezius and the latissimus dorsi.
The trapezius arises from the middle of the occipital bone,
and from the spine as far as the last dorsal vertebra. From
this extended line of origin the fibres converge to their in-
sertion in the acromion process and spine of the scapula.
The latissimus dorsi arises from the last six dorsal vertebrae,
and through the medium of the lumbar aponeurosis, from the
lumbar and sacral part of the spine and from the crest of the
ilium. The fibres pass upwards and converge into a thick, nar-
row band, which winds around and finally terminates in a flat
tendon, which is inserted into the front of the hurnerus just
below its head.
These muscles cover nearly the whole of the back ; but as
they act upon the bones of the upper extremity, they are often
more properly reckoned as belonging to the muscles of that
region.
The muscles of the thorax are chiefly concerned with the
movements of the ribs during respiration. They. are the inter-
costals, subcostals, etc.
The chief bulk of the anterior muscular wall of the chest is
made up of the pectoral muscles, which arise mainly from the
front of the sternum. The fibres converging form a thick mass,
which is inserted by a tendon of considerable breadth into the
upper part of the humerus. As these muscles move the arm,
they are, like the superficial muscles of the back, usually reck-
oned among the muscles of the upper extremity. Covering the
pectoral muscles is a superficial fascia (composed of connective
tissue) in which are lodged the mammary glands and a variable
amount of fat.
The muscular walls of the abdomen are mainly formed by
three layers of muscles, the fibres of which run in different direc-
tions, those* of the superficial and middle layers being oblique,
and those of the innermost layer being transverse. In front,
these three layers of muscles are replaced by tendinous expan-
sions or aponeuroses, which meet in the middle line, the line of
union giving rise to a white cord-like line, the linea alba. On
each side of this line the fibres of a straight muscle, the rectus
muscle, extend in a vertical direction between the tendinous
PLATE IV. — MUSCLES OF CHEST AND ABDOMEN. 55, pectoral muscle : 44, serratus
magnus ; 34, external oblique ; 35, rectus abdominis, the external layer of aponeurotic
sheath is removed ; 38, linea alba ; 40, aponeurosis.
63
UNIVERSITY OF CALIFORNIA
MEDICAL CENTER LIBRARY
SAN FRANCISCO
Gift of
Mrs. Ginellc Lemon
TEXT-BOOK
ANATOMY AND PHYSIOLOGY
FOR NURSES
COMPILED BY
/
DIANA CLIFFORD \ gIMBER
GEADUATE OP BELLEVUE TRAINING SCHOOL; ASSISTANT -SUPERINTENDENT NEW YORK CITY
TRAINING SCHOOL, BLACKWELL'S ISLAND, N. Y. ; FORMERLY ASSISTANT
SUPERINTENDENT ILLINOIS TRAINING SCHOOL, CHICAGO, ILL.
gorft
THE MACMILLAN COMPANY
LONDON: MACMILLAN & CO., LTD.
1899
All rights reserved
COPYRIGHT, 1893,
BY MACMILLAN AND CO.
Set up and electrotyped September, 1894. Reprinted
November, 1894; February, August, 1805 ; January, No-
vember, 1896; July, December, 1897; September, 1898;
July, 1899.
Nortooot)
J. S. CushinR & Co. - Berwick & Smith
Norwood Mas*. I'.S.A.
Uetucateti
TO MY
FRIEND, SCHOOLMATE, AND SUPERINTENDENT
ILoutse Barcfje
GRADUATE OF BELLEVUE TRAINING SCHOOL
AND
SUPERINTENDENT NEW YORK CITY TRAINING SCHOOL
BLACKWELL'S ISLAND, N.Y.
The following illustrations have been copied from Quain's
"Anatomy" and Schafer's "Essentials of Histology," and
are used in this work by permission of the authors and pub-
lishers of those books, viz. : Figs. 4, 5, 8, 10, 12, 14, 51, 53, 64,
69, 83, 86, 103, 110, 117, 121, 127, 128.
PKEFACB.
IN preparing the following pages for publication, it has been
my endeavour to keep the fact that I was writing for nurses,
constantly in mind. So far as I know, no attempt has yet
been made to compile a text-book on anatomy and physiology
for the use of nurses, although the subject is more or less
universally and systematically taught in our training schools.
During several years I have spent much time and trouble
in preparing notes on this subject for class-teaching, and it
was suggested to me that if these notes could be put into
shape, they might prove useful in our schools. The scheme
of the book has been practically worked out in class-teaching,
and in compiling the notes from standard works on anatomy
and physiology, I have sought to abstract that which shall
prove valuable and interesting to the nurse, while avoiding
those innumerable and minute details indispensable to the
medical student.
On first glancing through the following pages, it may be
thought that the structural elements of the tissues have been
dwelt upon at greater length than is at all necessary, and
that the whole subject has been thereby made unnecessarily
difficult. In reply to which I can only say that after repeated
experiments in teaching, this method has gradually revealed
itself to me as the most effectual one for making the subject
intelligible, and I have found, after careful instruction in
the structure of the tissues, the student most readily under-
stands the functions of the different parts of the body.
It is always well to bear in mind that the primary object of
educative methods is to enlarge the mental capacity of the
o
vii
vhi PREFACE.
student, and not to make her swallow a mass of undigested
facts. To insist upon accuracy of statement; to enlarge the
pupil's vocabulary; to train her to trace from cause to effect
in different conditions, — if nothing else is accomplished, this
is a great deal, and will make a nurse of distinctly greater
value and of higher grade, than one whose mind has not,
with all her training, been trained to think.
It seemed best to arrange the book in chapters rather
than in lessons, owing to the difficulty of making each sub-
ject of an equal length ; in the introductory contents, however,
a scheme of the subject, arranged in lessons of suitable length,
is provided. It is, perhaps, superfluous to suggest that in
making use of the text-book for class-teaching, each lesson
should be illustrated as far as possible by anatomical charts,
skeleton or manikin, and, where obtainable, by specimens from
the human subject.
The book has been compiled from the following works :
Quain's "Anatomy," edited by E. A. Schafer, F.R.S., and Prof.
G. D. Thane ; Gray's " Anatomy," edited by T. Pickering Pick ;
"Text-book of Physiology," by M. Foster, M.A.; "Physiology
and Hygiene," by T. H. Huxley, F.R.S., and D. J. Youmans,
M.D. ; " Human Physiology," by John C. Dalton, M.D. ; " The
Human Body," by H. Newell Martin, M.D. ; Woods' "House-
hold Practice of Medicine," edited by Fred. A. Castle, M.D. ;
"The Essentials of Histology," by E. A. Schafer, F.R.S. ;
"Practical Normal Histology," by F. M. Prudden, M.D.
I am specially indebted to my friend, Louise Darche, for invalu-
able assistance. Without her aid, the book would neither have
been begun, continued, or finished, and if it meets the require-
ments of our schools, it will be largely owing to her hearty co-oper-
ation and the criticism and advice given by her in every page.
NEW YORK, August 12, 1894.
CONTENTS.
ARRANGED IN CHAPTERS AND LESSONS.
CHAPTER I.
PAGB
(LESSON I.) Introductory — General Outline of the Body ; Different Parts
of the Body ; Structural Elements of the Tissues ; The Cell . . 1
CHAPTER II.
(LESSON II.) Origin of Tissues ; Epithelial Tissues ; Stratified ; Transi-
tional ; Simple 8
CHAPTER III.
(LESSON III.) Connective Tissues : Connective Tissue Proper ; Adipose or
Fat Tissue ; Reticular and Lymphoid Tissue. — (LESSON IV.) Carti-
lage ; Bone 13
CHAPTER IV.
(LESSON V.) The Skeleton ; Long and Short Bones. — (LESSON VI.) Flat
and Irregular Bones. — (LESSON VII.) General Review of Boiies . 23
CHAPTER V.
(LESSON VIII.) The Joints 47
CHAPTER VI.
(LESSON IX.) Muscular Tissues ; Striated or Striped ; Non-striated or
Plain — Attachment of Muscles to Skeleton. — (LESSON X.) Prominent
Muscles of the Head and Trunk. — (LESSON XI.) Prominent Muscles
of the Limbs 52
NOTE. — In most training schools in America instruction in class is given from
Oct. 1 to June 1, or for thirty-eight consecutive weeks: the lessons in this text-book
can be conveniently mastered in the first year's course, taken in the manner indi-
cated in these introductory contents.
ix
LIST OF ILLUSTRATIONS.
FIGURE PAGE
1. Diagrammatic Longitudinal Section of the Trunk and Head . . 2
2. Diagram of a Cell .......... 4
3. Consecutive Stages of Cell-Division, with Indirect Division of the
Nucleus 6
4. Section of Stratified Epithelium 9
5. Section of the Transitional Epithelium lining the Bladder ... 10
6. Simple Pavement Epithelium ........ 10
7. Simple Columnar Epithelium 11
8. Glandular Epithelium, with the Cells set round a Simple Saccular
Gland 11
9. Ciliated Epithelium from the Human Trachea . . . .11
10. Subcutaneous Areolar Tissue from a Young Rabbit .... 14
11. Fibrous Tissue from the Longitudinal Section of a Tendon . . 15
12. A Few Fat Cells from the Margin of a Fat Lobule .... 17
13. Articular Hyaline Cartilage from the Femur of an Ox ... 19
14. Transverse Section of Compact Tissue (of Humerus) ... 21
15. The Skeleton 24
16. The Clavicle 25
17. The Humerus 25
18. The Ulna and Radius 26
19. Bones of the Wrist and Hand 26
20. The Femur 27
21. Bones of the Right Leg 28
22. Bones of the Ankle and Foot 28
23. Occipital Bone 29
24. Parietal Bone 30
25. Frontal Bone 31
26. Nasal Bone 31
27. Lachrymal Bone 31
28. Voraer 32
29. Scapula 32
30. Sternum 33
31. Os Innominatum 34
32. Temporal Bone 35
33. Sphenoid Bone 36
34. Ethmoid Bone . 36
35. Malar Bone 37
36. Palate Bone 37
xiii
xiv LIST OF ILLUSTRATIONS.
FIOURB PAOB
37. Inferior Turbinated Bone 37
38. Superior Maxillary Bone . . . 37
39. Inferior Maxillary Bone 38
40. Hyoid Bone 38
41. A Cervical Vertebra 39
42. Side View of Spinal Column, without Sacrum and Coccyx . . 40
43. The Skull 41
44. The Skull at Birth 42
45. Male Pelvis 43
46. Female Pelvis «... 43
47. Thorax 44
48. A Toothed or Dentated Suture 47
49. A Mixed Articulation 49
50. A Simple Complete Joint 48
51. Muscular Fibre . * 52
62. Fragments of Striped Fibres showing a Cleavage in Opposite Direc-
tions ............ 53
63. Wave of Contraction passing over a Muscular Fibre of Dytiscus . 54
64. Fibre-Cells of Plain Muscular Tissue ....... 55
65. Muscles of Right Eyeball within the Orbit 58
66. Muscles of Eyeball 58
57. Muscles of the Tongue 60
58. Muscles of the Arm 66
69. Muscles in Front of Forearm ........ 67
60. Muscles of the Thigh 68
61. Muscles of the Leg. Superficial View of the Calf .... 69
62. Red and White Corpuscles of the Blood 75
63. The Heart and Lungs 82
64. Anterior View of Heart, dissected after long Boiling, to show the
Superficial Muscular Fibres ........ 83
65. Right Side of Heart 84
60. Left Side of Heart 85
67. Section of Heart at Level of Valves 85
68. Structure of an Artery 88
69. Part of a Vein laid Open 90
70. Portion of Endothelium of Peritoneum ...... 91
71 and 72. The Aorta 95
7:;. The Carotid, Subclavian, and Axillary Arteries 06
74. Deep Anterior View of the Arteries of the Arm, Forearm, and Hand 97
75. Iliac and Femoral Arteries 100
76. View of Popliteal Artery 101
77. Deep View of the Arteries of the Back of the Leg .... 102
78. Anterior View of Arteries jof the Leg 102
79. Arteries of the Foot 103
80. Sketch of the Principal Venous Trunks 104
81. Superficial Veins of Lower Extremity . . . . . . 105
W. Diagram of Circulation 109
8:). Isolated Capillary Network formed by the Junction of Several Hol-
lowed-out Cells, and containing Coloured Blood Corpuscles in a
Clear Fluid 118
LIST OF ILLUSTRATIONS.
xv
FIGURE PAOB
84. A Small Portion of a Lymphatic Plexus 120
85. Lymphatics and Lymphatic Glands of Axilla and Arm . . . 124
86. Diagrammatic Section of Lymphatic Gland ..... 125
87. Vertical Section of a Portion of a Peyer's Patch, with Lacteal
Vessels injected 126
88. The Mouth, Nose, and Pharynx, with the Commencement of Gullet
and Larynx 130
89. The Larynx as seen by Means of the Laryngoscope . . . .131
90. Front View of Cartilages of Larynx 132
91. Two Alveoli of the Lung 133
92. Anterior View of Lungs and Heart 134
93. Diagram showing the Various Forms of Secreting Structures . . 143
94. An Intestinal Villus 146
95. The Salivary Glands 155
96. The Mouth, Nose, and Pharynx, * with the Larynx and Commence-
ment of Gullet, seen in Section ....... 157
97. Vertical and Longitudinal Section of Stomach and Duodenum . . 159
98. An Intestinal Villus 160
99. Section through the Lymphoid Tissue of a Solitary Gland . . .161
100. Caecum, showing its Appendix, Entrance of Ilium, and Ileo-Csecal
Valve 162
101. Posterior View of Pancreas 163
102. Under Surface of Liver 164
103. Diagrammatic Representation of Two Hepatic Lobules . . . 165
104. Section of Rabbit's Liver, Vessels and Bile Ducts injected . . 166
105. The Renal Organs viewed from Behind 180
106. Section through the Kidney 182
107. Vascular Supply of Kidney 183
108. Plan of Blood- Vessels connected with the Tubules .... 184
109. Diagram of the Course of Two Uriniferous Tubules .... 185
110. Section of Epidermis 189
111. Section of Skin showing Two Papillae and Deeper Layers of Epidermis 191
112. Piece of Human Hair 192
113. Section of Skin showing the Hairs and Sebaceous Glands . . . 193
114. Coiled End of a Sweat-Gland 194
115. Multi-polar Nerve-Cell 200
116. Nerve-Fibres . .201
117. Section of the Internal Saphenous Nerve 202
118. Diagram illustrating the General Arrangement of the Nervous System 203
119. Side View of the Brain and Spinal Cord in Place . . . .204
120. The Base of the Brain 205
121. Transverse Sections of the Spinal Cord at Different Levels . . 211
122. Base of Brain, Spinal Cord, and Spinal Nerves 212
123. Sections of Spinal Cord and Nerve-Roots 213
124. General View of the Sympathetic System 214
125. Nerve Ending in Muscular Fibre of a Lizard 215
126. Section of Skin, showing Tactile Corpuscle in Papilla . . .216
127. End-Bulbs from the Human Conjunctiva 217
128. The Upper Surface of the Tongue 220
129. Vertical Longitudinal Section of Nasal Cavity 222
xvi LIST OF ILLUSTRATIONS.
130. Semi-diagrammatic Section through the Right Ear . . . .224
131. The Left Eyeball in Horizontal Section from before Back . . . 228
132. Diagrammatic Section of the Human Retina 230
133. Diagram illustrating Rays of Light converging in (4) a Normal
Eye, (£) a Myopic Eye, and (<7) Hypermetropic Eye . . . 233
134. The Lachrymal Apparatus 235
135. Section of Female Pelvis showing Relative Portion of Viscera . . 238
136. The Uterus and its Appendages ........ 240
137. Section of an Ovary 242
PLATES.
PLATE PAGB
I. Forms of Muscles and Tendons 57
II. Muscles of Face, Head, and Neck 59
III. Muscles of Back 61
IV. Muscles of Chest and Abdomen 63
V. The Abdominal Aorta and its Contents 99
VI. Plan of Foetal Circulation 116
VII. Regions of the Abdomen and their Contents 154
TEXT-BOOK
OF
ANATOMY AND PHYSIOLOGY FOE NUESES.
CHAPTER I.
INTRODUCTORY. — GENERAL OUTLINE OF THE BODY. — DIFFER-
ENT PARTS OF THE BODY. — STRUCTURAL ELEMENTS OF
THE TISSUES. — THE CELL.
Introductory. — In looking upon the fully developed human
body we are impressed with the complexity of its structure, the
perfection of its mechanism, the mysteriousness of its life. To
learn to understand something of this structure, this mechan-
ism, this life, is one of our most imperative duties as nurses; for
how can we appreciate the significance of abnormal functions,
and the seriousness of diseased conditions, unless we are ac-
quainted with the normal functions of the body, and have some
knowledge of healthy bodily conditions ?
In the following pages we propose to give a description of
the structure, of the position, and of the special work or func-
tion of each part of the body. We have dwelt specially upon
the structure of the different parts, believing that any correct
understanding of the bodily functions must be preceded by a
certain amount of knowledge concerning the structure of the
organs performing these functions.
Before taking up the subject in detail it is well, first of all,
to get a general idea of the main divisions, and the position of
the different parts, and we shall therefore begin our considera-
tion of the body with an outline of its structure.
General outline of the body. — It is readily seen that the human
body is separable into trunk, head, and limbs ; the trunk and
head are cavities, and contain the internal organs or viscera,
B 1
ANATOMY FOK NUKSES.
[CHAP. I.
while the limbs are solid or semi-solid, contain no viscera, and
are merely appendages of the trunk. The limbs or extremities,
upper and lower, are in pairs, and bear a rough resemblance to
one another, the shape of the bones, and the disposition of the
muscles in the thigh and arm, leg and forearm, ankle and wrist,
foot and hand, being very similar.
The trunk and head contain two main cavities, and looking
at the body from the outside we should naturally imagine that
these two cavities were the cavity of the
head and the cavity of the trunk, respec-
tively. If, however, we divide the trunk
and head lengthwise into two halves, by
cutting them through the middle line
from before backwards, we find the trunk
and head are divided by the bones of the
spine into back and front cavities, and
not into upper and lower (vide diagram).
The dorsal or back cavity is a com-
plete bony cavity, and is formed by the
vertebrae (bones of the spine) and of the
bones of the skull. It may be subdi-
vided into the spinal canal, containing
the spinal cord, and into the cranial cav-
ity, which is merely an enlargement of
the spinal canal, and contains the brain.
Connected with the dorsal cavity are the
FIG. i. — DIAGRAMMATIC two small orbital cavities containing the
LONGITUDINAL SECTION OF f { } t
THE TRUNK AND HEAD. 1,1, &
the dorsal cavity; a, the The ventral or front cavity is not a
'omplete bony cavity, part of its walls
bodies of the vertebrae form- being formed of muscular and other tis-
in- the partition between ... ,111
the dorsal and ventral cavi- sue 5 ^ ^ much larger than the dorsal
ties; 2, 2, the ventral cavity, cavity, and may be subdivided into the
subdivided into thoracic cav- *\ , , . , , , .
ity (d), abdominal cavity thoracic, abdominal, and pelvic cavities.
(e) and pelvic cavity (/); Th thoracic cavity, or chest, contains the
y, the nasal cavity; h, the J
month, or bnccai cavity, trachea or windpipe, the lungs, gullet,
heart, and the great vessels springing
the whole length of the ven- from, and entering into, the heart. The
abdominal cavity contains the stomach,
liver, gall-bladder, pancreas, spleen, kidneys, small and large
CHAP. I.] DIFFERENT PARTS OF THE BODY. 3
intestines, etc. The pelvic cavity contains the bladder, rectum,
and generative organs. Connected with the upper part of the
ventral cavity are two small cavities, the buccal cavity, or mouth,
containing the tongue, teeth, salivary glands, etc., and the nasal
cavity, containing the organ of smell.
Different parts of the body. — In speaking of the different parts
of the body, we usually call each part an organ, and we may say
that the human body is made up of organs, each organ being
adapted to the performance of some special work or function.
Thus the lungs are organs specially adapted for performing
the function of respiration, the bones are organs adapted for
support and locomotion, the kidneys for secreting urine, etc.
Every part or organ, when separated into minute fragments,
is found to consist of certain textures or tissues. When the
body is thus separated or dissected, and analyzed by the aid of
the microscope, we find that the number of distinct tissues is
comparatively small, and some of these again, although at first
sight apparently distinct, yet have so much in common in their
structure and origin one with another, that the number becomes
still further reduced, until we can only distinguish four distinct
tissues, viz. : —
The epithelial tissues. The muscular tissues.
The connective tissues. The nervous tissues.
Particles met with in the fluids of the body, such as the little bodies or cor-
puscles in the blood and lymph, are also reckoned among these elementary
tissues.
Some organs are formed of a combination of several of the
above tissues ; others contain only one or two. Thus the
muscles are made up almost entirely of muscular tissue with
only a small intermixture of connective tissue, blood-vessels,
and nerves ; whilst the ligaments or sinews are composed
wholly of a variety of connective tissue.
On the other hand, there are certain organs or parts of the
body not in themselves distinguished by the preponderance of
any tissue. Such are : —
Blood-vessels. Synovial membranes.
Lymphatic vessels. Mucous membranes.
Lymphatic glands and bodies Secreting glands.
of like structure. Integument or skin.
Serous membranes.
4 ANATOMY FOR NUKSES. [CHAP. I.
Thus, though we may say the greater bulk of the body is made
up of a combination of four distinct tissues, — the epithelial,
connective, muscular, and nervous, — there are parts in which
these tissues are so intimately mixed that we cannot distinguish
any distinct variety, and we are therefore obliged to class them
by themselves.
Structural elements of the tissues. — When any tissue is sep-
arated by the aid of the microscope into its simplest parts, such
parts are termed the structural elements of the tissue. The
simplest structural element of every tissue is a cell or fibre,1
and however diversified the tissues of the body may appear to
be, they all originate as collections of cells. All the varied
activities of the body are the result of the activity of the cells
which compose it, and it is very desirable, owing also to their
being the foundation of all structure (the bricks, as it were, out
of which the tissues are built), that we early acquire some defi-
nite conception of these tiny elementary bodies.
The cell. — A cell is a minute portion of living substance
called protoplasm, which is sometimes
enclosed by a cell membrane, and al-
ways contains a vesicle which is known
^ as the nucleus.
Up to 1865 it was universally believed
• — 2?* that protoplasm had no definite parts,
or, in other words, was structureless ;
A but> whei\ examined under the highest
CELL, n, nucleus ; p, proto- microscopical power, it appears as an
exceedingly fine network of delicate
fibres. The width of the meshes varies to some extent ; some-
times they are narrow and close, and sometimes wider and more
open. The interspaces are filled with a clear soft semi-fluid
substance and minute particles or granules of variable size. The
microscope can tell us little more than this, though there are good
grounds for supposing that there is structure that cannot be
directly observed. We have to turn to the chemical nature
of protoplasm for light as to the cause of its remarkable prop-
erties.
All matter of whatever kind is made up of little particles or
atoms, so small that they are perfectly invisible to the human
1 A fibre is merely a modified cell.
CHAP. I.] THE CELL. 5
eye even when aided by all the appliances of optical science,
and it is only when a number of these atoms unite into one
body that they become visible. Every little piece of matter
which we can see is built up of thousands, or rather millions, of
these atoms. There are many different kinds of atoms. Thus
we have carbon, hydrogen, oxygen, and other kinds, each having
its own particular weight, and probably its own particular size
and shape. They combine by mutual attraction, which in some
cases we call cohesion, and in others chemical affinity, accord-
ing as the atoms are of the same or of different kinds. In this
way an endless variety of structures may be built up. These
structures may be stable and solid, the myriads of atoms com-
posing them cohering so firmly together that it is almost impos-
sible to separate them ; or they may be very unstable, or complex,
the particles composing them being of many different kinds and
sizes, held together in the loosest fashion, and ready to fall apart
at the slightest touch. Again, we may have many structures
varying in stability between these two extremes.
Protoplasm is a highly complex structure, and its chemical
equilibrium is so unstable that it is ready to break down at the
least touch. It is extremely sensitive to any outside stimulus.
Slight influences cause it to alter its shape, move, and exhibit
other phenomena; these phenomena being mainly due to the
inter-action of the chemical affinities of which it is composed.
During the life of a cell its protoplasm is constantly under-
going changes, the chief of which may be enumerated as
follows : —
(1) All protoplasm coming in contact with oxygen absorbs
it and combines with it. Whenever this combination takes
place, a certain amount of the protoplasm is burned or oxidized,
and as a result of this oxidation heat and other kinds of energy
are produced, and carbonic acid evolved.
(2) All protoplasm is able to take into itself, and eventually
convert into its own substance, material that is non-living ; this
material or food is generally supposed to be a compound chem-
ical substance called proteid, which is a combination of nitrogen,
carbon, oxj^gen, and hydrogen. In this way the protoplasm
may increase in amount, or in other words the cell may grow;
but if the amount of protoplasm does not permanently increase,
this is due to the fact that just as much protoplasm is being
6
ANATOMY FOB NURSES.
[CHAP. I.
broken down by the process of oxidation, and removed from the
cell, as is added by the process of assimilation. Chemical
changes which involve the building up of living material within
the cell have received the general name of anabolic changes ;
those, on the other hand, which involve the breaking down of
such material into other and
simpler products, are known
as katabolic changes : while the
sum of all the ana- and kata-
bolic changes which are pro-
ceeding within the cell are
spoken of as the metabolism of
a cell. These chemical changes
are always more marked as the
activity of the cell is promoted
by warmth, electrical or other
stimulation, the action of cer-
tain drugs, etc.
(3) The most obvious phys-
ical changes which can be seen
in living protoplasm, by the aid
of the microscope, are those
which are termed "amoeboid."
This term is derived from the
fresh water amoeba, which has
long been observed to exhibit
spontaneous changes of form,
accompanied by a flowing of its
soft semi-fluid substance. By
virtue of this property, the cells
FIG. ?>.— A TO tf, CONSECUTIVE STAGES can move from one place to an-
OF CELL-DIVISION, WITH INDIRECT DIVIS- . TJ, . . ,, ,
ION OF THE NUCLEUS. (Diagrammatic.) other. It one ot these cells be
observed under a high power
of-ii microscope, it will be seen gradually to protrude a portion
of its protoplasm ; this protrusion extends itself, and the main
part or body of the cell passes by degrees into the elongated
protrusion. By a repetition of this process, the cell may glide
slowly away from its original situation and move bodily along
the field of the microscope, so that an actual locomotion takes
place. When the surface of these free cells comes in contact
CHAP. L] THE CELL. 7
with any foreign particle, the protoplasm, by virtue of its amo3-
boid movements, tends to flow round and enwrap the particles,
and particles thus enwrapped or incepted may then be conveyed
by the cell from one place to another.
The nucleus. — The nucleus of a cell is directly concerned in
the reproduction and division of the cells. In dividing, the
nucleus passes through a series of remarkable changes, which
are too complicated to be studied here. (See Fig. 3.) The
result of these changes is that either directly or indirectly the
nucleus splits into two, the protoplasm divides and arranges
itself around the new nuclei ; these daughter cells soon grow to
the size of the parent cell, and division of these and consequent
multiplication may proceed with great rapidity.
To sum up: The cell assimilates, is continually building
itself up, and replenishing its store of energy, is as continually
breaking down into simpler products, with a setting free of
energy ; it grows ; it moves ; it reproduces itself — in other
words, it is alive and is the basis of all life.
CHAPTER II.
ORIGIN OF TISSUES. — EPITHELIAL TISSUES : STRATIFIED, TRAN-
SITIONAL, SIMPLE.
Origin of tissues. — In the first chapter we stated that the body
is made up of different parts or organs, each having some
special work to do; each part is made up of tissues, of which
there are four distinctive kinds ; each tissue is made up of
structural elements, cells and fibres ; and finally, each fibre
being a modified cell, the cell is the basis of all the bodily
structures.
Thus, in the early embryo, the whole body is an agglomera-
tion of cells. These have all been formed from the ovum or
egg-cell, which divides into two cells; these again into two,
and so on until numbers of cells are produced. Eventually
these cells arrange themselves in the form of a skin or mem-
brane which is composed of three layers. These layers are
known respectively as the epiblast, or upper layer; the meso-
blast, or middle layer; the hypollast, or under layer. The
epiblast is supposed to give rise to the nervous tissue and most
of the epithelial tissue ; the mesoblast to the connective and
muscular tissues; the hypoblast to the rest of the epithelial
tissue. Of these tissues, the epithelial is the simplest, and most
nearly allied to the primitive tissue, and will first engage our
attention.
Epithelial tissue. — Epithelial tissue is composed entirely of
cells united together by cohesive matter. The cells are gener-
ally so arranged as to form a skin or membrane, covering the
external and internal surfaces of the body. This membrane is
seen when the skin is blistered, the thin and nearly transparent
membrane raised from the surface being epithelial tissue — in
this situation called epidermis, because it lies upon the surface
8
CHAP. II.] EPITHELIAL TISSUE. 9
of the true skin. In other situations, epithelial tissue usually
receives the general name of epithelium.
Classification. — We may classify the varieties of epithelium
according to the shape of the cells which compose them, or
according to the arrangement of these cells in layers. Adopt-
ing the latter and simpler classification, we distinguish three
main varieties: the stratified, consisting of many layers; the
transitional, consisting of two or three layers; the simple, con-
sisting of a single layer of cells.
1. Stratified epithelium. — The cells composing the different
layers of stratified epithelium differ in shape. As a rule, the
FIG. 4. — SECTION OF STRATIFIED EPITHELIUM, c, lowermost columnar cells;
P, polygonal cells above these ; fl, flattened cells near the surface. Between the
cells are seen intercellular channels, bridged over by processes which pass from cell
to cell.
cells of the deepest layer are columnar in shape ; the next,
rounded or many-sided, whilst those nearest the surface are
always flattened and scale-like, the protoplasm of the cell being
finally converted into a horn-like substance. The deeper soft
cells of a stratified epithelium are continually multiplying by
cell-division, and as the new cells which are thus produced
in the deeper parts increase in size, they compress and push
outwards those previously formed. In this way cells which
were at first deeply seated are gradually shifted outwards and
upwards, growing harder as they approach the surface. The
older superficial cells are being continually rubbed off as the
new ones continually rise up to supply their places.
Stratified epithelium covers the anterior surface of the eye,
lines the mouth, the chief part of the pharynx, the gullet, the
vagina, and part of the uterus, but its most extensive distribu-
tion is over the surface of the skin, where it forms the epider-
mis. Wherever a surface is liable to abrasion we find stratified
10 ANATOMY FOR NURSES. [CHAP. IL
scaly epithelium, and we may therefore classify it as a protec-
tive epithelium.
2. Transitional epithelium. — This is a modification of strati-
fied epithelium, consisting only of two or three layers of cells.
FIG. 5. — SECTION OF THE TRANSITIONAL EPITHELIUM LINING THE BLADDER.
(Highly magnified.) (E.A. S.) a, superficial; b, intermediate ; c, deep layer of cells.
The superficial cells are large and flattened, having on their
under surface depressions into which fit the larger ends of the
pear-shaped cells which form the next layer. Between the
tapering ends of these pear-shaped cells are one or two layers
of smaller, many-sided cells, the epithelium being renewed by
division of these deeper cells. This kind of transitional epithe-
lium lines the bladder and ureters.
3. Simple epithelium. — This is composed of a single layer of
cells. The cells forming single layers are of distinctive shape,
and have distinctive functions in different parts of the body.
The chief varieties are the pavement, col-
umnar, glandular, and ciliated.
In simple pavement epithelium the cells
form flat, many-sided plates or scales, which
fit together like the tiles of a mosaic pave-
ment. It forms very smooth surfaces, and
FIG. (I. — SIMPLE PAVE- ,. ,, ,
MENT EPITHELIUM, a, lmes the heart, blood-vessels, and lym-
from a serous membrane; phatics ; the mammary ducts, the serous
/', from ;i blood-vessel. . .
cavities, etc.
The columnar epithelium is a variety of simple epithelium in
which the cells have a prismatic shape, and are set upright on
the surface which they cover. In profile these cells look some-
what like a close palisade, their edges, however, being often
irregular and jagged, especially where free or " wander-cells "
CHAP. II.]
EPITHELIAL TISSUE.
11
squeeze in between them. Columnar epithelium is found in its
most characteristic form lining the mucous
membrane of the intestinal canal.
Glandular epithelium is found in the re-
cesses of secreting glands. The cells are of
many different shapes, and are usually set
round a tubular or saccular cavity, into
FIG. 7. — SIMPLE COL-
UMNAR EPITHELIUM, a,
the cells ; b, intercellular
which the secretion is poured. The proto- fubstanc« Between the
lower end of cells.
plasm of these cells is generally filled by
the materials which the
gland
secretes.
In ciliated epithelium the cells,
which are generally columnar in
shape," bear at their free extrem-
ities little hair-like processes
which are agitated incessantly
with a lashing or vibrating mo-
tion. These minute and delicate
processes are named cilia, and
may be regarded as active prolon-
gations of the cell-protoplasm.
FIG. 8. - GLANDULAR EPITHELIUM, The maimer in which cilia move
WITH THE CELLS SET ROUND A SIMPLE
SACCULAR GLAND. (Highly magnified.) is best seen when they are not
acting very quickly. The mo-
tion of an individual cilium may be compared to the lash-like
motion of a short-handled
whip, the cilium being rap-
idly bent in one direction.
The motion does not involve
the whole of the ciliated sur-
face at the same moment,
but is performed by the cilia
in regular succession, giv-
ing rise to the appearance of
a series of waves travelling
along the surface like the
waves caused by the wind
in a field of wheat. When
they are in very rapid action, their motion conveys the iilea of
swiftly running water.
FIG> 9. — CILIATED EPITHELIUM FROM THK
HUMAN TRACHEA. (Highly magnified.) a,
large ciliated cell ; d, cell, with two nuclei.
12 ANATOMY FOR NURSES. [CHAP. II.
Cilia have been shown to exist in almost every class of ani-
mal, from the highest to the lowest. In man their use is to
impel secreted fluids, or other matters, along the surfaces to
which they are attached; as, for example, the mucus of the
trachea and nasal chambers, which they carry towards the out-
let of these passages.
Ciliated epithelium is found in the air passages, the genera-
tive organs, ventricles of the brain, and central canal of the
spinal cord.
To recapitulate: The most important situations in which a
covering or lining of epithelial tissue is found in the body
are : —
1. On the surface of the integument, or external skin.
2. On mucous membranes, or internal skin.
3. On the inner surface of serous membranes, and on the
inner surface of the heart, blood-vessels, and lymphatics.
4. Lining the ventricles or cavities of the brain, and the
central canal of the spinal cord.
Some varieties of epithelium are specially modified to form
protective membranes ; others to elaborate or make secretions ;
others, again, to form smooth linings for opposing surfaces ;
and yet others to keep the surfaces they cover clean, by sweep-
ing outwards material that would otherwise accumulate, and
clog important passages.
The hairs, nails, and the enamel of the teeth, are modifica-
tions of epithelial tissue.
CHAPTER III.
CONNECTIVE TISSUES: CONNECTIVE TISSUE PROPER, ADIPOSE
OR FAT TISSUE, RETICULAR AND LYMPHOID TISSUE, CAR-
TILAGE, BONE.
FOLLOWING the classification of tissues we have adopted, the
next group of tissues to be studied is that known as the con-
nective tissue group. This includes : —
Connective tissue proper.
Adipose or fat tissue.
Reticular and lymphoid tissue.
Cartilage.
Bone.
These tissues differ considerably in their external character-
istics, but are alike in that they all serve to connect and support
the other tissues of the body ; they tend to pass imperceptibly
the one into the other ; there are many points of similarity
between the cells which occur in them, and we may, therefore,
reasonably group them together.
When connective tissue first begins to be formed as a distinc-
tive tissue, the cells which are set apart to form it are round in
shape and loosely packed together; later these cells begin to
throw out branches and to form a kind of network with open
spaces. In these open spaces a semi-fluid substance is deposited
which gradually becomes more consistent, and in this substance
is developed the particular fibres which are the chief structural
characteristics of connective tissue proper.
Our description of epithelial tissue was briefly this : a skin
or membrane formed of cells, which cells may be of a variety of
shapes, and be arranged in one or more layers. It is distinctly
a tissue of cells with very little of what we call intermediate or
13
14
ANATOMY FOE, NUKSES.
[CHAP. III.
intercellular substance lying between the cells. Connective
tissue differs from epithelial tissue in having a great deal of
intercellular substance between its cells, and according to the
manner in which this intercellular substance develops do we
get the different varieties of connective tissue.
Connective tissue proper. — There are three modifications of
connective tissue proper ; viz. the areolar, the fibrous, and
the elastic.
Areolar tissue. — If we make a cut through the skin, and pro-
ceed to raise it from the parts lying beneath, we observe that it is
loosely connected to them by a soft filmy substance of consider-
able tenacity and elasticity. This is areolar tissue. It is also
Vic.. 10. — SUBCUTANEOUS AREOLAR TISSUE FROM A YOUNG RABBIT. (Highly
magnified.) (E. A. S.) The white libres are in wavy bundles, the elastic fibres form
;tn open network, p, p, vacuolated cells; g, granular cell; c, c, branching lamellar
cells : c', a flattened cell, of which only the nucleus and some scattered granules are
visible;/, fibrillated cell.
found, in like manner, under the serous and mucous mem-
branes,1 and serves to attacli them to the parts which they line
or cover. Proceeding further, we find this areolar tissue lying
between the muscles, the blood-vessels, and other deep-seated
parts ; also forming investing sheaths for the muscles, the
1 These membranes line the internal cavities and surfaces of the body.
CHAP. 111.] CONNECTIVE TISSUE PKOPER. 15
nerves, the blood-vessels, and other parts. It both connects
and insulates entire organs, and, in addition, performs the same
office for the finer parts of which these organs are made up. It
is thus one of the most general and most extensively distributed
of the tissues. It is, moreover, continuous throughout the body,
and from one region it may be traced without interruption into
any other, however distanj, — a fact not without interest in prac-
tical medicine, seeing that in this way air, water, and other
fluids, effused into the areolar tissue ma}^ spread far from the
spot where they were first introduced or deposited.
Seen with the naked eye, areolar tissue appears to be com-
posed of a multitude of fine threads and films crossing irregu-
larly in every imaginable direction, leaving open spaces or
areolce between them. Viewed with the microscope, these
threads and films are seen to be principally made up of wavy
bundles of exquisitely fine, transparent, white fibres, and these
bundles intersect in all directions. Mixed with the white
fibres are a certain number of elastic fibres, which do not form
bundles, and have a straight instead of a wavy outline. The
cells of the tissue, of which there
are several varieties, lie in the | ,, w ,,
spaces between the bundles of |
fibres.
On comparing the areolar tissue
of different parts, it is observed in
some to be more loose and open in £
texture ; in others, more close and jj
dense, according as.free movement, fi
or firm connection between parts is I • >,j
to be provided for. /
Fibrous tissue. — Fibrous tissue is /
intimately allied in structure to
the areolar tissue, but the bundles /
of white fibres cohere very closely, (/' "' •(]
and instead of interlacing in every FIG. 11.— FIBROUS TISSUE, FROM
direction run for the most part in THE LONGITUDINAL SECTION OF A
TENDON. (After Gegenbauer.)
only one or two directions, and thus
confer a distinctly fibrous aspect on the parts which they com-
pose. This fibrous tissue is met with in the form of ligaments,
connecting the bones together at the joints, and in the form of
16 ANATOMY FOE, NURSES. [CHAP. III.
sinews or tendons, by means of which the muscles are attached
to the bones. It also forms fibrous membranes which invest
and protect different parts or organs of the body. Examples
of these are seen in the periosteum and perichondrium, which
cover the bones and cartilages, and in the dura mater, which
lines the skull and protects the brain. Fibrous membranes,
called fascia;, are also employed to envelop and bind down the
muscles of different regions, of which the great fascia, enclosing
the muscles of the thigh and leg, is a well-known example;
and, under the name of aponeuroses, serve for the attachment of
muscles in various parts of the body. It thus appears that
fibrous tissue presents itself in the form of strong bands or
cords, and of dense sheets or membranes.
Fibrous tissue is white, with a peculiarly shining silvery
aspect. It is exceedingly strong and tough, yet perfectly
pliant ; but it is almost devoid of extensibility. By these qual-
ities it is admirably suited to the purposes for which it is used
in the human frame. By its inextensile character, and by its
strength, it maintains in apposition the parts which it connects,
and we find that the ligaments and tendons do not sensibly
yield to extension in the strongest muscular efforts ; and though
they sometimes snap asunder, it is well known that bones will
break more readily than tendons ; and the fibrous membranes or
aponeuroses are equally strong, tough, and unyielding.
Elastic tissue. — In elastic tissue the wavy white bundles are
comparatively few and indistinct, and there is a proportionate
development of the elastic fibres. When present in large num-
bers they give a yellowish colour to the tissue. This form of
connective tissue is extensile and elastic in the highest degree,
but is not so strong as the fibrous variety, and breaks across the
direction of its fibres when forcibly stretched.
It occurs in its most characteristic form in what is called
the ligamenta subflava, which forms an elastic band between
some of the bones of the spine. Elastic tissue is also found in
the walls of the air tubes ; unites the cartilages of the larynx :
and enters largely into the formation of the walls of the blood-
vessels, especially of the arteries.
These three varieties of connective tissue agree closely with
one another in elementary structure. It is the different ar-
rangement of the cells and fibres, and the relative proportion of
CHAP. Ill,] ADIPOSE TISSUE. 17
one kind of fibre to the other, that gives them their different
characteristics : the interlacing of the wavy bundles of finest
fibres, giving us the delicate web-like areolar tissue ; the close
packing of these bundles, giving us the dense opaque fibrous
membranes and bands; and the preponderance of the elastic
fibres, furnishing the extensile elastic tissue.
This connective tissue proper, as we have already noted, is
used for purely mechanical purposes : forming inextensile bands
or pulleys ; strong protective membranes ; web-like, binding, and
supporting material ; sheaths of varying degrees of density ;
elastic bands or membranes ; and it also serves to carry the
blood-vessels, lymphatics, and nerves to the parts which it
connects and covers.
Adipose tissue. — When fat first begins to be formed in the
embryo, it is deposited in tiny droplets in some of the cells
FIG. 12. — A FEW FAT-CELLS FROM THE MARGIN OF A FAT-LOBULE. Very
highly magnified. /. g. fat-globules distending a fat-cell ; n, nucleus; ni. membran-
ous envelope of the fat-cell; c, capillary vessel; v, veinlet; c. t. connective-tissue
cell; the fibres of the connective tissue are not shown.
of the areolar connective tissue ; these droplets increase in size,
and eventually run together so as to form one large drop
in each cell. By further deposition of fat the cell becomes
swollen out to a size far beyond that which it possessed orig-
inally until the protoplasm remains as a delicate envelope sur-
18 ANATOMY FOR NURSES. [CHAP. III.
rounding the fat drop. As these cells increase in number they
collect into small groups or lobules, which lobules are for the
most part lodged in the meshes of the areolar tissue, and are
also supported by a fine network of blood-vessels. This fatty
tissue exists very generally throughout the body, accompanying
the still more widely distributed areolar tissue in most, though
not in all, parts in which the latter is found. Still, its distribu-
tion is not uniform, and there are some situations in which it
is collected more abundantly. It forms a considerable layer
underneath the skin, in the subcutaneous areolar tissue ; it is
collected in large quantity around certain internal parts,
especially the kidneys ; it is seen rilling up the furrows on the
surface of the heart; it is deposited beneath the serous mem-
branes, or is collected between their folds ; collections of fat
are also common around the joints, padding and filling up
inequalities; and, lastly, the fat exists in large quantities in
the marrow of bones.
Adipose tissue, unless formed in abnormal quantities, confers
graceful outlines upon the human frame ; it also constitutes an
important reserve fund, by storing up fatty materials, derived
from the food and brought to it by the blood, in such a form
and manner as to be readily reabsorbed into the circulation
when needed.
Retiform and lymphoid tissue. — These tissues closely resemble
the areolar variety of connective tissue, except that the bundles
of fibrils occurring in them are very much finer, and the meshes
of the open and fine network are filled with fluid and with
lymph cells. The reticular or retiform tissue forms the whole
framework of some of the organs of the body, and enters largely
into the formation of the mucous membranes. The lymphoid
or adenoid tissue composes the greater part of the lymphatic
glands, and other allied structures, and is found also in some
mucous membranes. These tissues will be more fully described
in connection with the organs in which they are found.
Cartilage. — This is the well-known substance called "gristle."
When a very thin section is examined with a microscope, it is
seen to consist of nucleated cells disposed in small groups in a
mass of intercellular substance. This intercellular substance
is sometimes transparent, and to all appearances homogeneous
or structureless ; sometimes dim and faintly granular, like
CHAP. III.]
CARTILAGE.
19
ground glass : both these conditions are found in what is called
^ true " or hyaline cartilage, and which is the most typical form
of the tissue. There is another
variety of cartilage in which the
intercellular substance is every-
where pervaded with fibres.
When the fibres are of the white
variety, it is called white fibro-
cartilaye; when they are elastic
fibres, it is called yellow or elastic
fibro-cartilage.
Although cartilage can be read-
ily cut with a sharp knife, it is
nevertheless of very firm consist-
ence, but at the same time highly
elastic, so that it readily yields
to extension or pressure, and im-
mediately recovers its original
shape when the constraining
force is withdrawn. By reason
of these mechanical properties it
serves important purposes in the
construction of some parts of the
body.
Hyaline cartilage occurs principally in two situations ; viz.
covering the ends of the bones in the joints, where it is known
as articular cartilage, and forming the rib cartilages, where it is
known as costal cartilage. In both these situations the carti-
lages are in immediate connection with bone, and may be said
to form part of the skeleton. The articular cartilages, in cov-
ering the ends or surfaces of bones in the joints, provide these
harder parts with a thick, springy coating, which breaks the
force of concussion, and gives ease to the motion of the joint.
The costal cartilages, in forming a considerable part of the
solid framework of the thorax or chest, impart elasticity to its
walls. Hyaline cartilage also enters into the formation of the
nose, ear, larynx, and windpipe. It strengthens the substance
of these parts without making them unduly rigid, maintains
their shape, keeps open the passages through them where such
exist, and gives attachment to moving muscles and connecting
ligaments.
\
J'.RKXAUDOT E.SALLE
FIG. 13. — ARTICULAR HYALINE
CARTILAGE FROM THE FEMUR OF AN
Ox. s, intercellular substance; p,
protoplasmic cell ; n, nucleus. (Ran-
20 ANATOMY FOR NUKSES. [CHAP. III.
Elastic or yellow fibro-cartilage is tougher and more flexible
than hyaline cartilage; it only occurs in parts of the throat
and ear.
White fibro-cartilage is found wherever great strength com-
bined with a certain amount of rigidity is required; thus we
find it joining bones together, the most familiar instance being
the flat round plates or disks of fibro-cartilage connecting the
bones of the spine and the pubic bones. White fibro-cartilage
very closely resembles white fibrous tissue.
Cartilage is not supplied with nerves, and very rarely with
blood-vessels. Being so meagrely supplied with blood the vital
processes in cartilage are very slow, and when a portion of it is
absorbed in disease or removed by the knife, it is regenerated
very slowly. A wound in cartilage is usually at first healed by
connective tissue proper, which may or may not become grad-
ually transformed into cartilage. Nearly all cartilages receive
their nourishment from the perichondrium which covers them,
and which is a moderately vascular fibrous membrane.
Bone. — Bone is a connective tissue in which the intercellular
or ground substance is rendered hard by being impregnated
with mineral salts.
On sawing up a bone it will be seen that it is in some parts
dense and close in texture, appearing like ivory, whilst in
others it is open and spongy, and we distinguish two forms of
bony tissue, the dense or compact, and the spongy or cancel-
lated. On closer examination, however, it will be seen that
the bony matter is everywhere porous, and that the difference
between the two varieties of tissue arises from the fact that the
compact tissue has fewer spaces and more solid matter between
them, arid that the cancellated has larger cavities and more
slender intervening bony partitions. In all bones the compact
tissue, being the stronger, lies on the surface of the bone, and
forms an outer shell or crust, whilst the lighter spongy tissue
is contained within. The shafts of the long bones are almost
entirely made up of the compact substance, except that they
are hollowed out to form a central canal — the medullary canal
— for the reception of the marrow. Marrow is also found in
the spongy portions of the bone in the spaces between the bony
partitions.
The hard substance of all bone is arranged in bundles of
CHAP. III.]
BONE.
21
bony fibres or lamella, which in the cancellated texture join
and meet together so as to form a structure resembling lattice-
work (cancelli), and whence this tissue receives its name. In
the compact tissue these lamellse are usually arranged in close
rings around canals which carry blood-vessels in a longitu-
dinal direction through the bones. Between the lamellge are
branched cells which lie in cell-spaces or cavities called lacunce,
and running out in a
wheel - like or radial
direction from each la-
cuna are numerous tiny
canals or canaliculi
connecting one cell-
space or lacuna with
another, and forming a
system of minute inter-
communicating chan-
nels.
All bones are cov-
ered by a vascular
fibrous membrane, the
periosteum, and, unlike
cartilage, the bones are
plentifully supplied
with blood. If we
strip this periosteum
from a fresh bone,
we see many bleeding ^ 14._TEANSvEESR SKCT.ON OF COMPACT
points representing the TISSUE (OF HUMERUS). (Magnified about loOdiam-
points at which the eterS-} (ShaW->. Three of the Ha versian canals
r are seen, with their concentric rings faintly indi-
blood- vessels penetrate cated ; also the lacunae, with the canaliculi extend-
ing from them across the direction of the encircling
lamellae, or concentric rings.
the bone. After en-
tering the bone the
blood runs through longitudinal channels which communicate
freely with one another, and are called, from the name of
their discoverer, Htiversian canals. Around these Haversian
canals, as we have already stated, the lamellse are disposed in
rings, while the lacunae containing the bone-cells are also
arranged, between the lamellse, in circles around the canals.
As the canaliculi run in a radial direction from the lacunse, it
22 ANATOMY FOK NUKSES. [CHAP. Ill
follows that the innermost ones must run into the Haversian
canals, so that there is a direct communication between the
blood in these canals and the cells in the lacunae. In this way
the whole substance of the bone is penetrated by intercom-
municating channels, and nutrient matters and mineral salts
from the blood in the Haversian canals can find their way to
every part.
The mineral or earthy substance which is deposited in bone,
and which makes it hard, amounts to about two-thirds of the
weight of the bone. It consists chiefly of phosphate of lime,
with about a fifth part of carbonate of lime, and a small portion
of other salts. The soft or animal matter consists chiefly of
blood-vessels and connective tissue, and may be resolved by boil-
ing almost entirely into gelatine : it constitutes about one-third
of the weight of the bone. This proportion of animal and earthy
constituents is, however, subject to variations. In children the
animal matter is apt to predominate, and we find that their
bones are more liable to be bent when injured, or only partially
broken, as in the typical "green-stick" fracture. Again, in aged
people the earthy constituents increase, the animal matter be-
comes deficient in quality and quantity, and consequently their
bones are brittle, and more liable to fracture.
In the re-union of fractured bones new bony tissue is formed
between and around the broken ends, connecting them firmly
together; and when a portion of bone dies, a growth of new
bone very generally takes place to a greater or less extent, and
the dead part is thrown off. The periosteum is largely con-
cerned in this process of repair ; for if a portion of the perios-
teum be stripped off, the subjacent bone will be liable to die,
while if a large part or the whole of a bone be removed, and
the periosteum at the same time left intact, the bone will
wholly, or in a great measure, be regenerated.
In the embryo the foundation of the skeleton is laid in cartilage, or in primi-
tive membranous connective tissue, ossification of the bones occurring later.
The hardening or ossification of the bones is accomplished by the penetration of
blood-vessels and bone-cells, called osteo-blasts, rfrom the periosteum. As
they penetrate into the cartilaginous or membranous models, they absorb the
cartilage and connective tissue and deposit the true bone tissue at various
points until they form the particular bony structure with which we are familiar.
CHAPTER IV.
THE SKELETON.
THE bones are the principal organs of support, and the pas-
sive instruments of locomotion. Connected together in the
skeleton, they form a framework of hard material, affording
attachment to the soft parts, maintaining them in their due
position, sheltering such as are of delicate structure, giving sta-
bility to the whole fabric, and preserving its shape.
The entire skeleton in the adult consists of two hundred dis-
tinct bones. These are : —
The spine, or vertebral column (sacrum and coccyx
included) 26
Cranium 8
Face 14
Os hyoides, sternum, and ribs 26
Upper extremities 64
Lower extremities 62
200
In this enumeration the patellce, or knee-pans, are included as
separate bones, but the smaller sesamoid bones, and the small
bones of the ear, are not included.
These bones may be divided, according to their shape, into
four classes : Long, Short, Flat, and Irregular.
The long and short bones are found in the extremities. The
flat and irregular bones are found in the trunk and head, with
the exception of the patellse, which are two small flat bones
found in the lower extremities, and the scapula, which are also
two flat bones usually reckoned among the bones of the upper
extremities.
The bones of the trunk and head are used chiefly to form
23
24
ANATOMY FOE NURSES.
[CHAP. IV.
FIG. 15.— THE SKELETON, a, parietal
bone; 6, frontal; c, cervical vertebrae; d,
sternum ; e, lumbar vertebrae ; /, ulna ; g, ra-
dius; ft, wrist or carpal hours; i, metacarpal
bones; k, phalanges; /, tibia: in, fibula; n,
tarsal bones; o, metacarpal; p, phalanges;
q, patella; r, femur; s, haunch-bone; t,
burner us ; u, clavicle.
cavities and to support and
protect the organs contained
in these cavities. The bones
of the extremities enclose no
cavities, and are chiefly used
in the upper extremity for
tact and prehension, and in
the lower for support and
locomotion ; in both situa-
tions they form a system of
levers. If the surface of any
bone is examined, certain
eminences and depressions
are seen, which are of two
kinds : articular and non-
articular. Non-articular pro-
cesses and depressions serve
for attachment of ligaments
and muscles ; the articular
are provided for the mutual
connection of joints.
Long bones. — A long bone
consists of a lengthened
cylinder or shaft and two
extremities. The shaft is
formed mainly of compact
tissue, this compact tissue
being thickest in the mid-
dle ; it is hollowed out in
the interior to form the
medullary canal. The ex-
tremities are made up of
spongy tissue with only a
thin coating of compact sub-
stance, and are more or less
expanded for greater con-
venience of mutual connec-
tion, and to afford a broad
surface for muscular attach-
ment. All long bones are
CHAP. IV.]
THE SKELETON.
25
FIG. 10. — THE CLAVICLE.
more or less curved, which confers upon them a certain amount
of elasticity, and gives them a more graceful outline.
Long bones of upper extremity : —
Clavicle (collar bone) 2
Humerus (arm) 2
Ulna'2 I (forearm) 4
Radius, 2 j v
Metacarpus (palm of the hand) 10
Phalanges (fingers) .' . . 28
46
The clavicle forms the anterior portion of the shoulder. It
articulates by its inner extremity with the sternum, and by its
outer extrem-
ity with the
acromion pro-
cess l of the
scapula. In
the female, the clavicle is generally less curved,
smoother, and more slender than in the male. In
those persons who perform considerable manual
labour, which brings into constant action the
muscles connected with this bone, it acquires
considerable bulk.
The humerus is the longest and largest bone
of the upper limb. The upper extremity of the
bone consists of a rounded head joined to the
shaft by a constricted neck, and of two eminences
called the greater and lesser tuberosities. The rounded head ; gt,
head articulates with the glenoid cavity of the ^at«r ^™£_
scapula. The constricted neck above the tuber- berosity;6,groove
osities is called the anatomical neck, and that
below the tuberosities, the surgical neck, from
its being often the seat of fracture. The lower extremity of the
1 All eminences and projections of bones are termed processes, and these
processes were named by the early anatomists, either from their shape or use,
or from their fancied resemblance to some well-known object. It is well to look
up the meaning of these Greek or Latin words which are used so plentifully in
naming all parts of the skeleton ; the whole subject will become more interest-
ing, more readily understood, and more easily remembered.
FIG. 17. — THE
HUMERUS. a,
26
ANATOMY FOK NQKSES.
[CHAP. IV.
bone is flattened from before backwards into a broad articular
surface, which is divided by a slight ridge into two parts, by
means of which it articulates with the ulna
and radius.
The ulna (elbow bone) is placed at the
inner side of the forearm, parallel with the
radius. Its upper extremity presents for
examination two large curved processes and
two concave cavities; the larger process
forms the head of the elbow, and is called
the olecranon process. The lower extremity
of the ulna is of small size, and is excluded
from the wrist by a piece of fibro-cartilage.
The radius is situated on the outer side
of the forearm. The upper end is small
and rounded with a shallow depression on
FIG. is. — THE ULNA its upper surface for articulation with the
AND RADIUS, i, radms; hunierus an(J a prominent ridge about it,
2, ulna; o, olecranon ..,.,'. , » ., ;, - , . ,
process, on the anterior like the head oi a nail, by means ot winch
surf ace of which are seen it rotates within the lesser sigmoid cavity
»
the large (gs) and the
small (Is) cavities, for of the ulna.
The
of the head of the radius, dius is large, and
radiuf^5 A> ^^ f formS the Chief Part
of the wrist.
Each metacarpus is formed by five
bones. These metacarpal bones are
curved longitudinally, so as to be con-
vex behind, concave in front ; they ar-
ticulate by their bases with the bones of
the wrist and with one another, and the
heads of the bones articulate with the
phalanges.
The phalanges, or digits, are the bones FTG- 10.- BUNKS
_ . WRIST AND HAND.
of the lingers; they are fourteen in metaearpal bones ; pi, p«, J>«,
number (in each hand), three for each phalanges; 3, bones of the
wrist.
finger, and two for the thumb. The
first row articulates with the metacarpal bones and the second
row of phalanges ; the second row, with the first and third ; and
the third, with the second row.
CHAP. IV.]
THE SKELETON.
27
Long bones of the lower extremity : —
Femur (thigh bone) ........... 2
*> ............ *
Metatarsus (sole and instep of foot) ..... 10
Phalanges (toes) ............ 28
44
The bones of the lower extremity correspond to those of the
upper extremity, and bear a rough resemblance to them.
The femur is the longest, largest, and strongest bone in the
skeleton. In the erect position it is not vertical, being sepa-
rated from its fellow above by a considerable in-
terval, which corresponds to the entire breadth
of the pelvis, but inclining gradually down-
wards and inwards, so as to approach its fellow
towards its lower part, for the purpose of bring-
ing the knee-joint near the line of gravity of
the body. The degree of inclination varies in
different persons, and is greater in the female
than the male, on account of the greater breadth
of the pelvis. The upper extremity of the
femur, like that of the humerus, consists of a
rounded head joined to the shaft by a constricted
neck, and of two eminences, called the greater
and lesser trochanters. The head articulates
with the cavity in the os innominatum, called
the acetabulum. The lower extremity of the.
femur is larger than the upper, is flattened from
before backwards, and divided into two large
eminences or condyles by an intervening notch.
It articulates with the tibia and the patella, or
knee-pan. FIG. 20. — THE
The tibia is situated at the front and inner FEMUR grounded
head; gtr, «jivntrr
side of the leg, and forms what is popularly trochanter;^, leas-
known as the shin bone. In the male, its direc- er trimmer; n,
11GC1C.
tion is vertical and parallel with the bone of the
opposite side ; but in the female it has a slight oblique direction
outwards, to compensate for the oblique direction of the femur
inwards. The upper extremity is large, and expanded into two
28
ANATOMY FOR NUKSEiS.
[CHAP. IV.
lateral eminences with concave surfaces which receive the con-
dyles of the femur. The lower extremity is much smaller than
the upper; it is prolonged downwards on its
inner side into a strong process, the internal
malleolus. It articulates with the fibula and
one of the bones of the ankle.
The fibula is situated at the outer side of the
leg. It is the smaller of the two bones, and, in
proportion to its length, the most slender of all
the long bones : it is placed nearly parallel with
the tibia. The upper extremity consists of an
irregular rounded head by
means of which it articu-
lates with the tibia. The
lower extremity is pro-
longed downwards into a
pointed process, the external
malleolus, which lies iust
K,,* im, J
FIG. 21.— BONES beneath the skin. It artic-
OF THE RIGHT LEG. ulates with the tibia and one
o, tibia; /, fibula; » ., -, e .-, n *,
etu and itu, lateral of the bones of the ankle,
eminences for re- The metatarsus is formed
ception of con- . _ , ,_.
dyies of femur; h, by five bones. Ihese meta-
head of fibula; im, tarsal bones closely resemble
internal malleolus; , '
em, external maiie- the metacarpal bones of the
olus- hand. Each bone articulates
with the tarsal bones by one extremity, and
by the other with the first row of phalanges.
The phalanges of the foot, both in number FIG. 22. — BONES OF
, , . THE ANKLE AND FOOT.
and general arrangement, resemble those in m\ to m5, metatarsai
the hand, there being two in the great toe bones 5 h> pi™i""-<-s;
, co, os calcis, or heel
and three in each of the other toes.
Short bones : —
Scaphoid.
Semilunar.
Cuneiform*
Pisiform.
Trapezium.
Tnipczoid.
Os magnum.
Unciform.
Bones of
" the carpus
or wrist.
bone.
Os ealcis.
Astragalus.
Cuboid.
Scaphoid.
Internal cuneiform.
Middle cuneiform.
External cuneiform. J
Bones of
the tarsus
or ankle.
CHAP. IV.] THE SKELETON. 29
The bones forming the wrists and ankles are small pieces of
bone irregularly shaped, and united together by ligaments
(vide Figs. 19 and 22). Their texture is spongy throughout,
excepting at their surface, where there is a thin crust of com-
pact substance : they are closely welded together, and yet, by
the arrangement of their ligaments, allow of a certain amount
of motion. There are eight carpal or wrist bones and seven
tarsal or ankle bones. The carpal bones are arranged in two
rows, upper and lower, between the bones of the forearm and
metacarpal bones. They are named, from their shape, scaphoid,
semilunar, cuneiform, etc. The tarsal bones are larger and
more irregularly shaped than the carpal. The largest and
strongest of these is the heel bone (os calcis), which serves to
transmit the weight of the body to the ground, and forms a
strong lever for the muscles of the calf of the leg.
FIG. 23. — OCCIPITAL BONE. Inner surface. 9, 9 and 10, 10, depressions for recep-
tion of lobes of brain; 11, foramen magnum.
Flat bones. — We find the bony tissue expands into broad or
elongated flat plates where the principal requirement is either
extensive protection or the provision of the broad surfaces for
30
ANATOMY FOR NUKSES.
[CHAP. IV.
muscular attachment. The flat bones are composed of two thin
layers of compact tissue, inclosing between them a variable
quantity of cancellous tissue. In the bones of the skull this
outer layer is thick and tough ; the inner one thinner, denser,
and more brittle. The cancellated tissue lying between the
two layers, or "tables of the skull," is called the diploe.
Flat bones of the head : —
Occipital ............. 1
Parietal ............ . . 2
Frontal .............. JL
4
The occipital bone is situated at the back and base of the
skull. At birth the bone consists of four parts, which do not
unite into a single-bone until about the sixth year. The internal
surface is deeply concave, and presents many eminences and de-
pressions for the
reception of parts
of the brain.
There is a large
hole — the fora-
men magnum -
in the more in-
terior portion of
the bone, for the
transmission of
the medulla ob-
longata, the en-
larged portion of
the spinal cord.
The- parietal
bones (paries, a
wall) form by
their union the
FIG. 24. — PARIETAL BONE. Inner surface. A, parietal de- sjcles a,^ roof of
)>i<->sion; E, furrow for ramification of arteries.
the skull. The
external surface is convex and smooth ; the internal surface is
concave, and presents eminences and depressions for lodging
the convolutions of the brain and numerous furrows for the
ramifications of arteries.
CHAP. IV.]
THE SKELETON.
31
The frontal bone resembles a cockle shell in form. It not
only forms the forehead, but also enters into the formation of
the roof of the orbits, and of the nasal cavity. The arch formed
FIG. 25. — FRONTAL BONE. Outer surface. 1, frontal eminence; 7, roof of orbital
cavity ; 10, orbital arch.
by part of the frontal bone over the eye is sharp and prominent
and affords that organ considerable protection from injury. At
birth the bone consists of two pieces, which afterwards become
united, along the middle line, by a suture which runs from the
vertex of the bone to the root of the nose. This suture usually
becomes obliterated within a few years after birth, but it occa-
sionally remains throughout life.
Flat bones of the face : —
Nasal 2
Lachrymal -2
Vomer 1
5
The two nasal bones are two small oblong
bones, varying in size and form in different in-
dividuals ; they are placed side by
side at the middle and upper part
of the face, forming by their junc-
tion "the bridge " of the nose.
FIG. 26. -NA- The lachrymal are the smallest
SAL BONE. Outer
surface. A, inter- and most fragile bones or the lace. FIG.-JT.— LAC n-
nai border; B, They are situated at the front part KYMAI. Boir«.
external border. J . Outer surface.
of the inner wall or the orbit, and
resemble somewhat in form, thinness, and size, a finger-nail.
32
ANATOMY FOR NURSES.
[CHAP. IV.
FIG. 28. — VOMER. Side view.
The vomer is a single bone
placed at the back part of the
nasal cavity, and forms part of
the septum of the nose. It is
thin, and shaped somewhat like
a plough-share, but varies in
different individuals, being frequently bent to one or the other
side.
Flat bones of the trunk : —
Scapula, shoulder-blade 2
Os innominatum, haunch-bone 2
Sternum, breast-bone 1
Ribs 24
Patella _2
31
The scapula, or
shoulder-blade, is a
large flat bone, tri-
angular in shape,
placed between the
first and eighth ribs
on the back part of the
thorax, where it affords
considerable protection to
the lungs. It is unevenly
divided by a very prominent
ridge, the spine of the scapula,
which terminates in a large trian-
gular projection called, from the
Greek, acromion process, or summit
of the shoulder. Below the acro-
mion process, and at the head of the
shoulder-blade, is a shallow socket,
the glenoid cavity, which receives
the head of the humerus.
The sternum, or breast-bone, is a
flat narrow bone, situated in the
median line in the front of the chest, , FIG 29.- SCAPULA inner sur-
face. 7, glenoid cavity ; 9, end of
and consisting, in the adult, of three spine; 10, acromion process.
CHAP. IV.]
THE SKELETON.
33
FIG. 30. — STERNUM. Front and side
view.
portions. It has been likened to an ancient sword. The upper
piece, representing the handle,
is termed the manubrium or
handle ; the middle and largest
piece, which represents the chief
part of the blade, is termed the
gladiolus ; and the inferior piece,
which is likened to the point of
the sword, is termed the ensiform
appendix. On both sides of the
upper and middle pieces are
notches for the reception of the
sternal ends of the ribs. The
ensiform appendix is cartilagi-
nous in structure in early life,
but is more or less ossified at
the upper part in the adult: it
has no ribs attached to it. The
sternum is about six inches long,
being rather longer in the male
than in the female.
The ribs are elastic arches of bone, forming the chief part
of the thoracic walls (vide Fig. 47). They are usually twelve
in number on each side. They are all connected behind with
the vertebrae of the spine, and the first seven pairs are con-
nected with the sternum in front through the intervention of
the costal cartilages : these first seven pairs are called from their
attachment the vertebro-sternal, or true ribs. The remaining
five pairs are termed false ribs ; of these, the first three, being
attached in front to the costal cartilages, are usually called the
vertebro-costal, while the two remaining, being unattached in
front, are termed vertebral, or floating ribs. The convexity of
each curved rib is turned outwards so as to give roundness to
the sides of the chest and increase the size of its cavity ; each
slopes downwards from its vertebral attachment, so that its
sternal end is considerably lower than its dorsal. The spaces
left between the ribs are called the intercostal spaces.
The os innominatum, or nameless bone, so called from bearing
no resemblance to any known object, is a large irregular-shaped
bone, which, with its fellow of the opposite side, forms the sides
34
ANATOMY FOE, NURSES.
[CHAP. IV.
and front wall of the pelvic cavity. In young subjects it con-
sists of three separate parts, and although in the adult these
have become united, it is usual to describe the bone as divisible
into three portions, — the ilium, the ischium, and the pubes. The
H
FIG. 31.— O8 INNOMINATUM. Outer surface. R, 0, crest of ilium, just below 0
is seen the upper anterior spinous process ; J, tuberosity of ischium ; T, part of
pubes, between J and T is seen the thyroid foramen ; H, acetabulum, below // is
seen end of pubic bone which, with its fellow of opposite side, forms the symphysis
pubis. (For further illustration, vide Figs. 45 and 4(5.)
ilium, so called from its supporting the flank, is the upper broad
and expanded portion which forms the prominence of the hip.
The ischium is the lower and strongest portion of the bone,
while the pubes is that portion which forms the front of the
pelvis. Where these three portions of the bone meet and finally
ankylose is a deep socket, called the acetabulum, into which the
head of the femur fits. Other points of special interest to note
in the ossa innominata are (1) the spinous processes formed by
CHAP. IV.] THE SKELETON. 35
the projections of the crest of the ilium in front, above and
below, the two upper or superior spinous processes being in par-
ticular well known and convenient landmarks used by surgeons
in making anatomical measurements ; (2) the largest foramen
in the skeleton, known as the door-like or thyroid foramen, sit-
uated between the ischium and pubes ; and (3) the symphysis
pubis, or pubic articulation, which also serves for a convenient
landmark in making measurements.
The patella, or knee-cap, is a small, flat, triangular bone, placed
in front of the knee-joint. It is generally regarded as analogous
to the olecranon process of the ulna, which also occasionally
exists as a separate piece of bone. The knee-cap serves to pro-
tect the front of the knee-joint.
Irregular bones. — The irregular bones are those which, on
account of their peculiar shape, cannot be grouped under either
of the preceding heads.
Irregular bones of the head : —
Temporal 2
Sphenoid 1
Ethmoid 1
4
The temporal bones are situated at the sides and base of the
skull. They are named temporal from the Latin word, tempus,
time, as it is on the temple the
hair first becomes gray and thin,
and thus shows the ravages of
time. The temporal bones are
divided into three parts : the
hard, dense portion, called pe-
trous ; a thin and expanded
scale-like portion, called squa-
mous ; and a mastoid portion,
which is perforated by numerous
holes and contains a number of FlG 32. — TEMPORAL BONE. Outer
Cells. The internal ear, the es- surface. 1, squamous portion ; 7, ex-
, . , . , , £ , ternal opening of auditory canal m
sentiai part ot the organ 01 near- petrous portion ; 8, mastoid portion ; 3,
ing, is Contained in a Series of glenoid cavity for reception of condyle
., _ . . of lower jaw.
cavities, channelled out of the
substance of the petrous portion. Between the squamous and
36
ANATOMY FOE, NURSES.
[CHAP. IV,
petrous portions is a
socket for the recep-
tion of the condyle of
the lower jaw.
The sphenoid bone
(sphen, a wedge) is
situated at the ante-
rior part of the base
FIG. 33. — SPHENOID BONE. Anterior surface. 6, of the skull, articulat-
greater wing ; 17, lesser wing.
cranial bones, which it binds firmly and solidly together
form it somewhat resembles a bat with
extended wings.
The ethmoid bone is an exceedingly
light, spongy bone, placed between the
two orbits and at the root of the nose,
contributing to form a part of each of
these cavities. The portion of the
bone situated at the back of the nose,
and closing the skull cavity in front,
is pierced by numerous holes, through
which the nerves, conveying the sense
of smell, pass. Descending from this
perforated plate, on either side of the
nasal cavity, are two masses of very
thin, spongy, bony tissue.
The irregular bones of the face : —
In
FIG. 34. — ETHMOID BONE.
Posterior surface. 2, cribri-
form, or perforated plate.
Malar 2
Palate 2
Inferior turbinated 2
Superior maxillary 2
Inferior maxillary 1
9
The malar or cheek bones form the prominence of the cheek,
and part of the outer wall and floor of the orbit.
The palate bones form (1) the back part of the roof of the
mouth ; (2) part of the floor and outer wall of the nose ; and
(3) a very small portion of the floor of the orbit.
CHAP. IV.]
THE SKELETON.
37
The inferior turbinated bones are situated on the outer wall
of each side of the nostril. Each consists of a layer of thin,
FIG. 35. — MALAR BONE. Outer surface. FIG. 36. — PALATE BONE. Inner surface.
spongy bone, curled upon itself like a scroll ; hence its name,
" turbinated."
The superior maxillary is one of the most important bones
of the face, in a surgical point of
view, on account of the number of
diseases to which some of its parts
are liable. With its fellow of the
opposite side, it forms the whole of
the upper jaw. Each bone assists
in forming part of the floor of the
orbit, the floor and outer wall of the nose, and the greater part
of the roof of the mouth. That part of the bone which con-
Outer Surface.
FIG. 37. — INFERIOR TURBINATED
BONE. Convex surface
focww
FIG. 38. — SUPERIOR MAXILLARY BONK. Outer surface.
38
ANATOMY FOK NUKSES.
[CHAP. IV.
Ceroneid process.
QmdyU.
for facM artery.
-AngU.
tains the teeth is called the alveolar process, and is excavated
into cavities, varying in depth and size according to the size of
the teeth they contain. There are eight cavities in each bone :
those for the canine teeth are the deepest ; those for the molars
are widest and subdivided into minor cavities; those for the
incisors are single, but deep and narrow.
The inferior maxillary, or lower jaw, is the largest and
strongest bone of the face, and serves for
the reception of the lower teeth. At birth,
it consists of two lateral halves, which join
and form one bone during the first or sec-
ond year. The lower jaw undergoes sev-
eral changes in shape during life, owing
mainly to the first
and second denti-
tion, to the loss of
teeth in the aged,
and the subsequent
absorption of that
part of the bone
which contained
them. It articulates, by its condyles, with the sockets in the
temporal bones.
The hyoid, os hyoides, or tongue bone, is an isolated, U-shaped
bone lying in front of the throat, just
above " Adam's apple " ; it supports the
tongue, and gives attachment to some of
its numerous muscles.
The irregular bones of the trunk are
comprised in the spine, which is formed
of a series of bones called vertebrae.
The vertebrae are thirty-three in num-
ber, and according to the position they
occupy are named : —
Cervical 7
Dorsal . 12
Lumbar 5
Sacral 5
Coccygeal 4
33
FIG. 39. — INFERIOR MAXILLARY BONE. Outer surface.
FIG. 40. — HYOID BONE.
CHAP. IV.]
THE SKELETON.
39
The vertebrse in the upper three portions of the spine are
separate throughout the whole of life ; but those found in the
sacral and coccygeal regions are, in the adult, firmly united, so
as to form two bones, five entering into the upper bone or
sacrum, and four into the terminal bone of the spine, or coccyx.
Each vertebra consists of two essential parts, an anterior
solid portion or body, and a posterior portion or arch. The
bodies of the vertebrse
are piled one upon
another, forming a
solid, strong pillar,
for the support of the
cranium and trunk,
the arches forming a
hollow cylinder be-
hind for the protec-
tion of the spinal
cord. Each arch has
seven processes: four
articular, two trans- FIG. 41. — A CERVICAL VERTEBRA. Inferior sur-
Verse and One SDi- ^ace- *> spinous process, slightly bifid ; 4, transverse
** process ; 5, articular process, inferior surface. Below
nOUS process. The the arch, or hollow portion, is seen the solid portion,
different vertebrae are or body-
connected together by means of the articular processes, and by
disks of intervertebral nbro-eartilage placed between the ver-
tebral bodies, while the transverse and spinous processes serve
for the attachment of muscles which move the different parts of
the spine. In the cervical region of the vertebral column the
bodies of the vertebrse are smaller than in the dorsal, but the
arches, are larger; the spinous processes are short, and are often
cleft in two, or bifid. The first and second cervical vertebrae
differ considerably from the rest. The first, or atlas, so named
from supporting the head, has practically no body, and may be
described as a bony ring divided into two sections by a trans-
verse ligament. The dorsal section of this ring contains the
spinal cord, and the ventral or front section contains the bony
projection which arises from the front of the second cervical ver-
tebra, or axis. This bony projection, or odontoid process, is
really the body of the atlas, which in early life separates from its
own vertebra and grows on the axis. Around this peg the atlas
40
ANATOMY FOR NURSES.
[ClIAP. IV.
A—
rotates when the head is turned from side to side, carrying the
skull, to which it is firmly articulated,
with it. The bodies of the dorsal ver-
tebrae are larger and stronger than
those of the cervical; they contain
depressions for the reception of the
vertebral ends of the ribs. The bodies
of the lumbar vertebrae are the largest
and heaviest in the whole spine. The
sacrum, formed by the union of the
five sacral vertebrae, is a large trian-
gular bone situated like a wedge
between the ossa innominata ; it is
curved upon itself in such a way as
to give increased capacity to the pel-
vic cavity (vide Fig. 46). The coccyx
(cuckoo's bill) is usually formed of
four small segments of bone, and is
the most rudimentary part of the
vertebral column.
The vertebral column as a whole. —
The spinal column in a man of aver-
age height is about twenty-eight
inches long. Viewed from the side
it presents four curvatures ; one, with
the convexity forwards in the cervi-
cal region, is followed in the dorsal,
by a curve with its concavity towards
the chest. In the lumbar region the
curve has again its convexity for-
wards, while in the sacral and coccy-
geal regions the concavity is turned
inwards. These curvatures confer a
considerable amount of springiness
FIG. 42. -SIDE VIEW OF SPI- upon t^e gpinal column wnich would
NAL COLUMN, WITHOUT SACRUM L
AND COCCYX, i to 7, Cervical be lacking were it a straight column :
vertebn,; s t« in dorsal verte- th elasticity is further increased by
brae ; 20 to 24, lumbar vertebrae ; J
A, A, spin.. us processes; c, D, the disks of fibro-cartilage lying be-
axis. the vertebrae. These disks or pads
CHAP. IV.]
THE SKELETON.
41
also mitigate the effects of concussion arising from falls or
blows, and allow of a certain amount of motion between
the vertebrae. The amount of motion permitted is greatest
in the cervical region. Between each pair of vertebrae are
apertures through which the spinal nerves pass from the spinal
cord.
The skull as a whole. — The skull, formed by the union of the
cranial and facial bones already described, is divisible into cra-
nium or brain case, and the anterior region or face.
FIG. 43. —THE SKULL, a, nasal bone ; 6, superior maxillary ; c, inferior maxillary ;
d, occipital ; e, temporal ; /, parietal ; g, frontal bone.
The bones of the cranium begin to develop at a very early
period of foetal life, owing to the importance of the organ they
have to protect. Before birth the bones at the top and sides of
the skull are separated from each other by membranous tissue
in which bone is not yet formed. The spaces occupied by this
membranous tissue are termed the fontanelles, so named from
the pulsations of the brain, which can be seen in some of them,
42 ANATOMY FOR NURSES. [CHAP. IV.
rising like the water in a fountain. There are six of these
fontanelles. The anterior fontanelle is the largest, and is a
lozenge-shaped space between the angles of the two parietal
and two frontal bones. The posterior
fontanelle is much smaller in size, and
is a triangular space between the occip-
ital and two parietal bones. The other
(A four fontanelles, two on each side of
the skull, are placed at the inferior
angles of the parietal bones : they are
unimportant. T]^e posterior fontanelle
is closed by an extension of the ossify-
ing process a few months after birth.
FIG. 44.— THE SKULL AT ,-., . . ,., ,,
BIRTH. Superior surface, i, The anterior remains open until the
posterior fontanelle; 2, sagit- second year, and occasionally persists
tel suture ; 4, anterior f on- i , -i • /• mi i • , i in
taneiie; A, A, bi-parietai throughout lite. I he base of the skull
diameter; B, B, bi-temporai js mucn thicker and stronger than the
walls and roof ; it presents a number
of openings for the passage of the cranial nerves, blood-ves-
sels, etc.
The diameters of the foetal skull given by King are : —
Occipito-mental (from posterior fontanelle to chin) . . 5-|- inches.
Occipito-frontal (centre of frontal bone to occiput) . . 4|- inches.
Bi-parietal (from one parietal prominence to another) . 3^- inches.
The fcetal cranial bones being imperfectly ossified, and their
edges separated by membranous intervals, they are readily
moulded, and they overlap one another more or less during
parturition.
The pelvic cavity. — The pelvis, so called from its resemblance
to a basin, is stronger and more massively constructed than
either the cranial or the thoracic cavity. It is composed of
four bones, the ossa innominata forming sides and front, and
the sacrum and coccyx, completing it behind. It is divided
by a brim or prominent line, the linea ilio-pectinea, into the
false and true pelvis. The false pelvis is all that expanded
portion of the pelvis situated above the brim : it forms an in-
complete or " false " basin. The true pelvis is all that portion
situated below the brim. Its cavity is a little wider in every
CHAP. IV.] THE SKELETON. 43
direction than the brim itself, while the false pelvis is a great
FIG. 45. — MALE PELVIS.
deal wider. The brim is, therefore, a somewhat narrower bony
FIG. 46. — FEMALE PELVIS.
44
ANATOMY FOR NURSES.
[CHAP. IV.
ring or aperture between these two ; hence it is often termed
the "strait." The bony pelvis is a basin without a bottom.
J.UESg&RD.
FIG. 47. — THORAX. 1 to 12, ribs ; d, d, costal cartilages; e, upper end of sternum;
6, middle portion of sternum ; la, first dorsal vertebra ; 12a, twelfth dorsal verte-
bra; 7a, seventh cervical vertebra; 1 to 7, true ribs; 8 to 12, false ribs; 11, 12, float-
ing ribs.
The opening where the bottom ought to be is the inferior strait
or outlet. The female pelvis differs from that of the male in
those particulars which render it better adapted to parturition,
notably in being altogether wider in every direction, which
gives more room for the child to pass ; in being altogether shal-
CHAP. IV.]
THE SKELETON.
45
lower, which lessens the distance through which the child has
to be propelled; and lastly, in the bones being thinner and
smoother.
The diameters of an average female pelvis given by King
are : —
Antero-posterior diameter of brim or inlet .... 4 inches.
Transverse diameter of brim or inlet 4 inches.
Oblique diameter of brim or inlet 4J to 5 inches.
Antero-posterior of outlet 4J to 5 inches.
Transverse of outlet 4 inches.
Oblique of outlet 4 inches.
The thoracic cavity. — The thorax or chest is an elongated,
conical-shaped cage, formed by the sternum and costal cartilages
in front, the twelve ribs on each side, and the bodies of the
twelve dorsal vertebrse behind. It contains and protects the
principal organs of respiration and circulation.
TABLE OF THE BONES.
HEAD.
Cranium.
Face.
Occipital.
Nasal.
Parietal.
Lachrymal.
Temporal.
Malar.
Frontal.
Superior maxillary, i
Ethmoid.
Inferior maxillary. •
Sphenoid.
Palate.
Inferior turbinated.
Vomer. /
Os hyoides.
7 cervical.
12 dorsal.
Vertebrse - 5 lumbar.
5 sacral, or sacrum.
4 coccygeal. or coccyx.
Ribs.
Sternum.
Ossa innominata.
TRUNK.
46
ANATOMY FOR NURSES.
[CHAP. IV.
Clavicle.
Humerus.
Ulna.
Radius.
Metatarsus.
Scaphoid.
Semi lunar.
Cuneiform.
Pisiform.
Trapezium.
Trapezoid.
Os magnum.
Unciform.
Phalanges or digits.
Carpus
Femur.
Tibia.
Fibula.
Metatarsus.
Os calcis.
Astragalus.
Cuboid.
Tarsus \ Scaphoid.
Internal cuneiform.
Middle cuneiform.
External cuneiform.
Phalanges or digits.
CHAPTER V.
JOINTS.
THE various bones of which the skeleton consists are con-
nected together at different parts of their surfaces, and such
connections are called joints or articulations.
In all instances some softer substance is placed between the
bones, uniting them together, or clothing the opposed surfaces ;
but the manner in which the several pieces
of the skeleton are thus connected varies
to a great degree. We distinguish three
varieties ; viz. those which are (1) immov-
able, (2) slightly movable, (3) freely
movable.
The immovable articulations. — The bones
of the cranium and the facial bones (with
the exception of the lower jaw) have
their adjacent surfaces applied in close
contact, with only a thin layer of fibrous tissue or of cartilage
placed between their margins. In most of the cranial bones
this union occurs by means of toothed
edges which fit into one another and
form jagged lines of union known as
sutures. The suture between the fron-
tal and parietal bones is called the
coronal suture; between the parietal
FIG.49.-AMIXEDARTICU- and occipital, the lambdoidal; and be-
LATION. a, 6, disk of fibro-car- tween the two parietal bones, along the
tilage; c, articular cartilage; .^ j. Qn the t Qf the crown,
a, bone.
the sagittal suture.
The slightly movable or mixed articulation. — In this form of
articulation the bony surfaces are usually joined together by
47
48
ANATOMY FOR NURSES.
[CHAP. V.
broad, flattened disks of fibre-cartilage, as in the articulations
between the bodies of the vertebrae. These intervertebral
disks being compressible and extensile, the spine can be moved
to a limited extent in every direction. In the pelvis the articu-
lation between the two pubic bones (symphysis pubis), and
between the sacrum and ilia (sacro-iliac articulation), are also
slightly movable. The pubic bones are united by a disk of
fibro-cartilage and by ligaments. In the sacro-iliac articulation
the sacrum is united more closely to the ilia, the articular sur-
faces being covered by cartilage and held together by ligaments.
The movable articulations. — This division includes the com-
plete joints, — joints having a secreting membrane placed be-
tween their opposing surfaces, which keeps them well lubricated
and capable of free movement one upon the other. Each articular
end of the bone is covered by cartilage, which provides surfaces
A of remarkable smoothness, and
these surfaces are lubricated by
the synovial fluid secreted from
the delicate synovial membrane
which lines the cavity of the
joint. This membrane is contin-
uous with the margin of the ar-
ticular cartilage, and along with
them completely encloses the
joint cavity. The bones are
united by fibrous connective
tissue in the various forms of
ligaments, such as membranous
capsules, flat bands, or rounded cords. These ligaments are not
always so tight as to maintain the bones in close contact in all
positions of the joint, but are rather tightened in some positions
and relaxed in others, so that in many cases they are to be looked
upon chiefly as controllers of movements, and not as serving
solely to hold the bones together. The bones are likewise held
together in these joints by atmospheric pressure and by the
surrounding muscles.
The varieties of joints in this class have been determined
by the kind of motion permitted in each. They are as
follows : —
(1) Gliding joint. The articular surfaces are nearly flat,
SVNOVIAL. FOUD
JOINT-CAVITY
FIG. 50. — A SIMPLE COMPLETE JOINT.
The synovial membrane is represented
by dotted lines.
CHAP. V.] JOINTS. 49
and admit of only a limited amount of gliding movement,
as in most of the articulations of the wrist and ankle, and in the
joints between the articular processes of the vertebrae.
(2) Hinge joint. The articular surfaces are of such shape
as to permit of movement, to and fro, in one plane only, like a
'door on its hinges. These movements are called flexion and
extension, and may be seen in the articulation of the arm with
the forearm, in the ankle joint, and in the articulations of the
phalanges.
(3) Ball and socket joint. In this form of joint a more or
less rounded head is received into a cup-like cavity, as the head
of the femur into the acetabulum, and the head of the humerus
into the glenoid cavity of the scapula. Movement can take
place freely in any direction, but the shallower the cup, the
greater the extent of motion.
(4) Pivot joints. In this form, one bone rotates around
another which remains stationary, as in the articulation of the
atlas with the axis, and in the articulation of the ulna and
radius. In the articulation of the ulna and radius, the ulna
remains stationary and the radius rotates freely around its
upper end. The hand is joined to the lower end of the radius,
and the radius, in rotating, carries the hand with it; thus, the
palm of the hand is alternately turned upwards and down-
wards. When the palm is turned upwards, the attitude is
called supination ; when downwards, pronation.
The different kinds of movement of which bones thus con-
nected are capable are, — flexion and extension ; abduction and
adduction ; rotation and circumduction.
A limb is flexed, when it is bent; extended, when it is
straightened out. It is abducted, when it is drawn away from
the middle line ; adducted, when it is brought to the middle
line. It is rotated, when it is made to turn on its own axis;
circumducted, when it is made to describe a conical surface, by
rotation around an imaginary axis. No part of the body is
capable of perfect rotation, as a wheel, for the simple reason that
sucli motion would necessarily tear asunder all the vessels,
nerves, muscles, etc., which unite it with other parts.
As the synovial membranes are intimately connected with
the joints, it may be well to give a brief description of
them here.
50 ANATOMY FOR NURSES. [CHAP. V.
The synovial membranes are composed entirely of connective
tissue, with the usual cells and fibres of that tissue. They are
distinguished by the nature of their secretion, which is a viscid,
glairy fluid, resembling the white of an egg and named synovia.
From its nature, it is well adapted for diminishing friction, and
thereby facilitating motion.
These membranes are found surrounding and lubricating the
cavities of the movable joints in which the opposed surfaces
glide on each other ; in these situations they are called articular
synovial membranes. They are found forming sheaths for the
tendons of some of the joints, and thus facilitating their motion
as they glide in the fibrous sheaths which bind them down
against the bones; they are here called vaginal synovial mem-
branes, or synovial sheaths. Lastly, they are found in the form
of simple sacs, interposed, so as to prevent friction, between two
surfaces which move upon each other, and in these situations
they take the name of bursal synovial membranes, or synovial
bursse. These bursso may be either deep seated or subcu-
taneous. The former are, for the most part, placed between a
muscle and a bone, or between a tendon and a bone. The sub-
cutaneous burs86 lie immediately under the skin, and occur in
various parts of the body, interposed between the skin and
some firm prominence beneath it. The large bursa situated
over the patella is a well-known example of this class, but
similar, though smaller, bursee are found also over the olecranon,
the malleoli, the knuckles, and other prominent parts.
TABLE OF JOINTS.
1. Synchondrosis. — A thin layer of cartilage is inter-
posed between the bones to which it adheres
closely on each side.
SYNARTHROSIS,
2. Suture. — A thin layer of fibrous tissue is inter-
OR. *s
T posed between the bones. Sutures may be den-
IMMOVABLE JOINT.
tated, tooth-like; serrated, saw-like; squamous,
scale-like ; harmonic, smooth ; and grooved, for
the reception of thin plates of bone.
1. Symphysis. — The bones are united by a plate or
disk of fibro-cartilage of considerable thickness;
AMPHIARTHROSIS,
OR
or by articular cartilages lined by a partial syno-
vial membrane.
SLIGHTLY MOVABLE 0 ., . . ,_, , ., , ,
2. Syndesmons. — 1 he bony surfaces are united by
an intrrosscoiis ligament, as in the lower tibio-
fibular articulation.
CHAP. V.]
JOINTS.
DlARTHROSIS,
OR
MOVABLE JOINT.
1. Arthrodia. — Gliding joint; articulates by plane
surfaces which glide upon each other.
2. Ginglymus. — Hinge joint; moves backwards and
forwards in one plane.
3. Enarthrosis. — Ball and socket joint; articulates
by a globular head in a cup-like cavity.
4. Diartlirosis rotataria. — Articulates by a pivot
process turning within a ring, or by a ring turn-
ing round a pivot.
CHAPTER VI.
MUSCULAR TISSUE : STRIATED OR STRIPED ; NON-STRIATED OR
PLAIN; ATTACHMENT OF MUSCLES TO SKELETON; PROMI-
NENT MUSCLES OF HEAD AND TRUNK ; PROMINENT MUSCLES
OF LIMBS.
MUSCULAR tissue is the tissue by means of which the active
movements of the body are produced. It is a higher kind of
tissue than the connective, which, as we have seen, is used
chiefly for mechanical purposes. Muscular tissue is irritable,
and if we irritate or stimulate it, it will respond. We may irri-
tate or stimulate the bones, ligaments,
or other connective tissue structures
and they will not respond, they will
remain immovable ; if, however, we
stimulate muscular tissue, it will show
its response to the stimulation by
contracting. This power of the
muscle to contract is called muscular
contractility. All muscular tissue
consists of fibres, and whenever a
muscle fibre contracts, it tends to
bring its two ends, with whatever may
be attached to them, together. Influ-
ences which irritate or stimulate
muscle fibres are spoken of under
the general name of stimuli.
Muscle fibres are of two different
kinds, and we therefore distinguish
two varieties of muscular tissue, the striped or striated, and the
plain or non-striated. The striated muscle is nearly always
under the control of the will, and is often spoken of as voluntary
62
FIG. 51. — MUSCULAR FIBRE.
Highly magnified. (E. A. S.)
The nuclei are seen on the flat at
the surface of the fibre, and in
profile at the edges: the sar-
coleuiina is not seen.
CHAP. VI.]
THE MUSCLES.
53
muscle ; the non-striated is usually withdrawn from the control
of the will, and is often termed involuntary muscle.
Voluntary, striated muscle is composed of long slender fibres
measuring on an average about -%$-$ inch in diameter, but hav-
ing a length of an inch or more. Each fibre consists of three dis-
tinct elements : (1) contractile substance, forming the centre and
making up most of the bulk of the fibre ; (2) nuclei, which lie
scattered upon the surface of the contractile substance ; (3) the
sarcolemma, a thin, structureless tube, which tightly encloses
the contractile substance and the nuclei.
If we examine a fresh muscle fibre microscopically, we see
that the contractile substance is marked with very fine indistinct
longitudinal lines, or strise; and if we treat the fibre with
certain chemical agents,
we find by slightly teas-
ing it with a needle, or
some other delicate instru-
ment, that it breaks up
along the longitudinal
lines into a number of fine
fibrils or fibrillse. Again,
if we examine the fibre
still further, we find that
in addition to the
tudinal striation it
crossed by more
narrow dark and light
bands Or Stripes, the rela- transverge cleavage; «, ~b, partially detached
tive width of the Stripes disks; &' detached disk, more highly magnified,
•, . ,1 showing the sarcous elements.
varying according as the
fibre is seen in a state of contraction or relaxation. So that if
now we soak a fibre in an acid solution for twenty-four hours,
and then tease it, we find that instead of breaking up longitudi-
nally into fibrill^e, it breaks across into thin disks. We thus see
that by breaking up in these two directions we may conceive of
the fibre as being resolvable into a multitude of tiny structures,
which elementary structures have been called sarcous elements.
It is believed by many observers that these sarcous elements are
definite aii^ independent structures, and that they are joined
together side by side, and end to end, by a peculiar cementing
s
FIG. 52. — FRAGMENTS OF STRIPED FIBRES,
SHOWING A CLEAVAGE IN OPPOSITE DIREC-
TIONS. (Magnified 300 diameters.) A, longitu-
dinal cleavage; c, fibrillae separated from one
another at the broken end of the fibre; c' c",
single fibrils more highly magnified, in c' the ele-
mentary structures are square, in c" round; B,
54
ANATOMY FOK NURSES.
[CHAP. VI.
R
substance ; this, however, is not proved, and the ultimate struct-
ure of muscular fibre is still by no means fully understood. This
much, however, is certain, that the contractile substance is a com-
plex chemical structure, and that the molecules of which it
is composed readily change their places under the influence of
certain stimuli. When a muscle contracts, each section or
sarcous element of the fibre broadens and shortens. This
broadening and shortening is brought about by the molecules
of each section of the fibre
changing their places. We
shall have a rough image of the
movements of the molecules
during a muscular con traction
if we imagine a company of
a hundred soldiers ten ranks
deep, with ten men in each
rank, rapidly, but by a series
of gradations, extending lat-
erally into a double line
with fifty men in each
line.
The striated muscles are
all connected with nerves,
and under normal conditions
do not contract otherwise
than by the agency of the
nerves. They are also plenti-
fully supplied with blood-
vessels.
The muscular fibres lie
closely packed, their ends
lapping over on to adjacent
FIG. 53. -WAVE OF CONTRACTION PASS- fibres, and forming bundles.
ING OVER A MUSCULAR FIBRE OF DYTLSCUS.
Very highly ma-nified. if, K, portions of Ihese bundles are grouped
**
.
and in this way the muscles
which are attached to the skeleton are formed.
Involuntary, non-striated muscular tissue is composed of long,
somewhat flattened, elongated fibre-cells. Each fibre-cell con-
tains an oval or rod-shaped nucleus, containing one or more
CHAP. VI.] THE MUSCLES. 55
nucleoli. The substance of the fibre-cell is longitudinally stri-
ated, but does not exhibit transverse striation. The fibre-cells
lie side by side, or lap over one another at the ends, and are
joined together by a small amount of cement substance.
This kind of muscular tissue is found arranged around the
blood-vessels and most of the hollow viscera. The fibres are
variously grouped in different parts of the body ; sometimes
crowded together in solid bundles, which
are arranged in layers and surrounded by
connective tissue, as in the intestines ;
sometimes arranged in narrow interlacing
bundles, as in the bladder; sometimes wound
in single or double layers around the blood-
vessels ; and again, running in various direc-
tions and associated with bands of connec-
tive tissue, they form large compact masses,
as in the uterus.
Numerous nerves are supplied to non-
striated muscular tissue, and many blood-
vessels.
The contraction of this kind of muscular
tissue is much slower and lasts longer than
the contraction of the striated variety. As
i i ,1 T c ,1 11, FIG. 54. — FIBRE-CELLS
a general rule the muscles of the skeleton OF PLAIN MUSCULAR
are thrown into contraction only by nervous TISSUE. Highly magni-
impulses reaching them along their nerves ;
spontaneous contractions, as in a case of "cramps," being rare
and abnormal. The plain muscular tissue of the internal
organs, however, very often contracts independently of the
central nervous system, and under favorable circumstances will
continue to do so after the viscera have been removed from the
body.
The great increase in the muscular tissue of the uterus during gestation
takes place both by elongation and thickening of the pre-existing fibre-cells,
and also, it is thought, by the development of new fibre-cells from .small
granular cells lying in the tissue. In the shrinking of the uterus after par-
turition the fibre-cells diminish to their previous size ; many of them become
filled with fat granules, and eventually many are, doubtless, removed by
absorption.
Development of striated muscular tissue. —When the muscular fibres
are about to be formed, the cells set apart for this purpose elongate, and their
56 ANATOMY FOR NURSES. [CHAP. VI.
nuclei multiply, so that each cell is converted into a long, multi-nucleated
protoplasmic fibre. At first the substance of the fibre is not striated, but
presently it becomes longitudinally striated along one side, and about the
same time a delicate membrane, the sarcolemma, may be discovered bound-
ing the fibre; then transverse striation commences, and gradually extends
around the fibre, and, finally, the nuclei take up their position under the
sarcolemma.
Regeneration of muscular tissue. — It was formerly thought that after
removal, by the knife, or by disease, muscular tissue was not regenerated,
but that any breach of continuity which might occur in the muscle was filled
up by a growth of connective tissue. It would appear, however, that the
breach is after a certain lapse of time bridged across by muscular substance,
but how the new muscular tissue is formed is not fully understood.
Attachment of muscles to the skeleton. — The muscles are sepa-
rate organs, each muscle having its own sheath of connective
tissue. The connective tissue extends also into the muscle, form-
ing sheaths for the smaller bundles, connecting and binding the
fibres and bundles together, and conducting and supporting the
blood-vessels and nerves distributed to the muscle fibres.
The muscles vary greatly in shape and size. In the limbs
they are of considerable length, forming more or less elongated
straps ; in the trunk they are broad, flattened, and expanded,
forming the walls of the cavities which they enclose.
They are attached to the bones, cartilages, ligaments, and
skin in various ways, the most common mode of attachment
being by means of tendons. The muscular fibres converge as
they approach their tendinous extremities, and gradually blend
with the fibres of the tendons, the tendons in their turn insert-
ing their fibres into the bones. Sometimes the muscles end in
expanded form in the* flat fibrous membranes, called aponeuroses.
Again, in some cases, the muscles are connected with the bones,
cartilages, and skin, without the intervention of tendons or
aponeuroses.
In the description of muscles it is customary to speak of the
attachments of their opposite ends under the names of origin
and insertion, the first term being usually applied to the
more fixed attachment, and the second to the more movable
attachment.
The muscular tissue or flesh forms a large proportion of the
weight of the whole body. The following has been calculated
for a man of one hundred and fifty pounds' weight from the
p-
PLATE I. — FORMS OF MUSCLES AND TENDONS. A, adductor of thigh ; B, biceps of
arm; 1), deltoid; G, gastroenemius ; P', pronator of fore-arm; P", pectoral; A',
rectus abdomiuis; R", rectus muscle of thigh; S', serratus magnus of thorax; 6'",
semi-membranosus of thigh.
57
58
ANATOMY FOE, NURSES.
[CHAP. VI.
tables of Liebig: skeleton, twenty-eight pounds; muscles, sixty-
two pounds ; viscera (with skin, fat, blood, etc.), sixty pounds.
The total number of voluntary muscles may be stated at
three hundred and eleven. It is not necessary for us to be able
to distinguish more than a few of the most prominent. We
may conveniently classify these into two groups : —
1. Chief muscles of the head and trunk.
2. Chief muscles of the limbs.
Chief muscles of head, face, neck, and trunk. — The chief
muscles of the head are the occipital and frontal muscles,
which, united together by a thin
aponeurosis extending over and
covering the whole of the upper
part of the cranium, are usually
known as one muscle, the occipito-
frontalis. The frontal portion of this
muscle is the more powerful ; by
its contraction the eyebrows are ele-
vated, the skin of the forehead
FIG. 55. — MUSCLES OF RIGHT
EYEBALL WITHIN THE ORBIT.
Seen from the front. 21, superior thrown into transverse wrinkles, and
rectus; 22, inferior rectus: 23, ex- fi soaln drawn forward
ternal rectus; 24, internal rectus;
25, superior oblique; 26, inferior
oblique.
\
There are about thirty facial mus-
cles ; they are chiefly small, and con-
trol the movements of the eye, nose, and mouth.
The six muscles which move the eyeball are the four straight
or recti, and the two oblique,
muscles. The four recti have a
common origin at the bottom
of the orbit ; they pass straight
forwards to their insertion into
the eyeball, one, the superior
rectus, in the middle line above ;
one, the inferior rectus, oppo-
site it below, and one half-way
on each side, the external and
internal recti. The eyeball is
Completely imbedded in fat, and from side- 1!)' elevator muscle of eyelid;
22-2(5, same as in Fig. 55.
these muscles turn it as on a
cushion, the superior rectus inclining the axis of the eye upwards,
FIG. 56.— MUSCLES OF EYEBALL. Seen
PLATE II. — MUSCLES OF FACE, HEAD, AND NECK. 1, sterno-cleidomastoid ;
10, temporal ; 11, masseter ; 13, 13, occipito-f routalis.
59
60
ANATOMY FOE, NURSES.
[CHAP. VI.
the inferior downwards, the external outwards, the internal
inwards. The two oblique muscles are both attached on the
outer side of the ball ; their action is somewhat complicated,
but their general tendency is to roll the eyeball on its own
axis, and pull it a little forward and inward.
The muscles of mastication are the masseter, the temporal, and
the external and internal pterygoid. They all have their origin
in the immovable bones of the skull, and are all inserted into
the movable lower jaw. They generally act in concert, bring-
ing the lower teeth forcibly into contact with the upper ; they
also move the lower jaw forward upon the upper, and in every
direction necessary to the process of grinding the food.
The chief muscles connecting
the tongue and tongue bone to
the lower jaw are the genio-
glossus and stylo-glossus. They
are interesting to us from the
fact that during general anaes-
thesia they, together with the
other muscles, become relaxed,
and it is necessary to press the
angle of the lower jaw upwards
and forwards in order to pre-
vent the tongue from falling
backwards and obstructing the
larynx.
The most prominent muscle
of the neck is the sterno-cleido-
mastoid. It is named from its origin and insertion, arising from
part of the sternum and clavicle, and being inserted into the
mastoid portion of the temporal bone. This muscle is easily
recognized in thin persons by its forming a cord-like promi-
nence obliquely situated along each side of the neck. It serves
as a convenient landmark in locating the great vessels carrying
the blood to and from the head. If one of these muscles be
either abnormally contracted or paralyzed, we get the deformity
called wry neck.
The muscles of the trunk may be arranged in three groups :
(1) muscles of the back ; (2) muscles of the thorax ; (3) muscles
of the abdomen.
FIG. 57. — MUSCLES OF THE TONGUE.
PLATE III.— MUSCLES OF BACK. 50, latissimus dorsi ; 51, trapezius ; 52, deltoid
61
62 ANATOMY FOli NUKSES. [CHAP. VI.
The muscles of the back are disposed in five layers, one be-
neath another. The two largest and most superficial are the
trapezius and the latissimus dorsi.
The trapezius arises from the middle of the occipital bone,
and from the spine as far as the last dorsal vertebra. From
this extended line of origin the fibres converge to their in-
sertion in the acromion process and spine of the scapula.
The latissimus dorsi arises from the last six dorsal vertebrae,
and through the medium of the lumbar aponeurosis, from the
lumbar and sacral part of the spine and from the crest of the
ilium. The fibres pass upwards and converge into a thick, nar-
row band, which winds around and finally terminates in a flat
tendon, which is inserted into the front of the humerus just
below its head.
These muscles cover nearly the whole of the back ; but as
they act upon the bones of the upper extremity, they are often
more properly reckoned as belonging to the muscles of that
region.
The muscles of the thorax are chiefly concerned with the
movements of the ribs during respiration. They. are the inter-
costals, subcostals, etc.
The chief bulk of the anterior muscular wall of the chest is
made up of the pectoral muscles, which arise mainly from the
front of the sternum. The fibres converging form a thick mass,
which is inserted by a tendon of considerable breadth into the
upper part of the humerus. As these muscles move the arm,
they are, like the superficial muscles of the back, usually reck-
oned among ,the muscles of the upper extremity. Covering the
pectoral muscles is a superficial fascia (composed of connective
tissue) in which are lodged the mammary glands and a variable
amount of fat.
The muscular walls of the abdomen are mainly formed by
three layers of muscles, the fibres of which run in different direc-
tions, those' of the superficial and middle layers being oblique,
and those of the innermost layer being transverse. In front,
these three layers of muscles are replaced by tendinous expan-
sions or aponeuroses, which meet in the middle line, the line of
union giving rise to a white cord-like line, the linea alba. On
each side of this line the fibres of a straight muscle, the rectus
muscle, extend in a vertical direction between the tendinous
PLATE IV. —MUSCLES OF CHEST AND AKPOMKN. .",:>, pectoral muscle ; 44, serratus
magnus ; 34, external oblique ; 35, rectus alxl. .minis, the external layer of aponeurotic
sheath is removed; 38, linea alba; 40, aponeurosis.
63
64 ANATOMY FOR NURSES. [CHAP. VI.
layers. The abdominal muscles are covered and lined by sheets
of fasciae, some of which are very dense and strong, and serve
to strengthen weak points in the muscular walls.
The strongest and most superficial of the abdominal muscles
is the external oblique, the fibres of which, arising from the lower
eight ribs, incline downwards and forwards and terminate in the
broad aponeurosis, which, meeting its fellow of the opposite side
in the linea alba, covers the whole of the front of the abdomen.
The lowest fibres of the aponeurosis are gathered together in
the shape of a thickened band, which extends from the superior
spinous process of the ilium to the pubis, and forms the well-
known and important landmark, called from the anatomist who
first described it, Poupart's ligament. Just above this ligament,
and near the pubic bone, is an oblique opening which transmits
the spermatic cord in the male, or the round ligament in the
female. This opening, called the external abdominal ring, is
often the seat of hernia.
The internal oblique muscle lies just beneath the external
oblique. Its fibres run upwards and forwards, and end for the
most part in a broad aponeurosis. At the outer border of the
rectus muscle this aponeurosis divides into two layers, one pass-
ing before, the other behind, that muscle : they reunite at its
inner border in the linea alba, and thus form a sheath for the
rectus.
The transversalis muscle lies beneath the internal oblique;
the greater part of its fibres have a horizontal direction, and
extend forward to a broad aponeurosis in front.
The rectus is a long, flat muscle, consisting of vertical fibres
situated at the fore part of the abdomen, and enclosed in
the fibrous sheath formed by the aponeuroses of the internal
oblique. It arises from the pubis, and is inserted into the car-
tilages of the fifth, sixth, and seventh ribs ; it is separated from
the muscle of the other side by a narrow interval which is occu-
pied by the linea alba.
The linea alba, or white line, is a tendinous band formed by
the union of the aponeuroses of the two oblique and transverse
muscles, the tendinous fibres crossing one another from side to
side. It extends perpendicularly, in the middle line, from the
ensiform portion of the sternum to the pubis. It is a little
broader above than below, and a little below the middle it is
CHAP. VI.] THE MUSCLES. 65
widened into a flat circular space, in the centre of which is sit-
uated the cicatrix of the umbilicus.
The abdominal muscles perform a threefold action. When
the pelvis and thorax are fixed, they compress the abdominal
viscera by constricting the cavity of the abdomen, in which
action they are much assisted by the descent of the diaphragm.
By these means the foetus is expelled from the uterus, the
faeces from the rectum, the urine from the bladder, and its con-
tents from the stomach, in vomiting. If the spine is fixed,
these muscles raise the diaphragm by pressing on the abdominal
viscera, draw down the ribs, compress the lower part of the
thorax, and assist in expiration. If the thorax is fixed, and
the trunk and arms raised and fixed, they draw the pelvis
upwards as a preparatory step to the elevation of the lower
limbs in the action of climbing.
The diaphragm is a thin musculo-fibrous partition, placed
obliquely between the abdominal and thoracic cavities. It is
fan-shaped, and consists of muscle fibres arising from the whole
of the internal circumference of the thorax, and of an aponeu-
rotic tendon, shaped somewhat like a trefoil leaf, into which
the muscle fibres are inserted. ( Vide Plate V. for illustration
of diaphragm.) It has three large openings for the passage
of the aorta, the large artery of the body, the inferior vena
cava, the largest vein of the body, and the oesophagus or gullet ;
it has also some smaller openings, of less importance, for the
passage of blood-vessels, nerves, etc. The upper or thoracic
surface of the diaphragm is highly arched; the heart is sup-
ported by the central portion of the arch, the right and left
lungs by the lateral portions, the right side of the arch being
slightly higher on the right than on the left side. The lower
or under surface of the diaphragm is deeply concave, and covers
the liver, stomach, pancreas, spleen, and kidneys.
The action of the diaphragm modifies considerably the size
of the chest, and the position of the thoracic and abdominal
viscera, and it is essentially the great respiratory muscle of the
body. The mechanical act of respiration consists of two sets
of movements; viz. those of inspiration and of expiration, in
which air is successively drawn into the lungs and expelled
from them by the alternate increase and diminution of the
thoracic cavity. The changes in the capacity of the thorax are
66
ANATOMY FOR NURSES.
[CHAP. VI,
effected by the expansion and contraction of its lateral walls,
called costal respiration, and by the depression and elevation
of the floor of the cavity, through contraction and relaxation
of the diaphragm, called dia-
phragmatic or abdominal respi-
ration. These two movements
are normally combined in the
act of respiration, but in dif-
ferent circumstances one of
them may be resorted to
more than the other. Abdom-
inal respiration predominates
in men and in children, and
costal respiration in women.
In the act of inspiration the
diaphragm contracts, and in
contracting flattens out and
descends, the abdominal vis-
cera are pressed downwards,
and the thorax is expanded
vertically. In normal and
quiet expiration the diminu-
tion of the capacity of the
chest is mainly due to the re-
turn of the walls of the chest
to the condition of rest, in con-
sequence of their own elastic
reaction, and of the elasticity
and weight of the viscera dis-
placed by inspiration. In more
forcible acts of expiration, and
in efforts of expulsion from
the thoracic and abdominal
cavities, all the muscles which
tend to depress the ribs, and
those which compress the ab-
dominal cavity, concur in pow-
erful action to empty the lungs, to fix the trunk, and to expel the
contents of the abdominal viscera. Thus the diaphragm is an
expulsive as well as the chief respiratory muscle of the body.
FIG. 58. — MUSCLES OF ARM. 58, biceps
5(J, triceps.
CHAP. VI.]
THE MUSCLES.
67
Muscles of the upper extremity.
— A certain number of muscles
situated superficially on the trunk
pass to the bones of the shoulder
and of the arm, so as to attach
the upper limbs to the trunk. Of
these, the two superficial muscles
we have mentioned as covering
the back, the trapezius and latis-
simus dorsi, and pectoral muscles
covering the front of the chest,
are the chief. The most promi-
nent muscles found in the upper
limbs are : —
Deltoid.
Biceps.
Triceps.
Pronators.
Supinators.
Flexors.
Extensors.
The deltoid is a coarse triangu-
lar muscle covering the top of
the shoulder; it extends down-
wards and is inserted into the
middle of the shaft of the hu-
merus. It raises the arm from the
side so as to bring it at right
angles to the trunk.
The biceps is a long fusiform
muscle, occupying the whole of
the anterior surface of the arm ;
it is divided above into two
portions or heads, from which
circumstance it has received its
name. It arises by these two
heads from the shoulder-joint,
and is inserted into the radius.
It flexes the forearm on the arm.
FIG. 59. — MUSCLES IN FRONT OF
ihe triceps is situated on the FOREARM. 6i>, proimtor tores :<;:;.»;:..
back of the arm, extending- the (;<i> (57» flexors; 70, supinator i-
. 71. 77, 78, extensors: </, annular nga-
whole length of the posterior sur- mellt.
68
ANATOMY FOR NUHSES.
[CHAP. VI.
face of the humerus. It
is of large size, and divided
above into three heads ;
hence its name. It is
inserted into the ulna.
It is the great extensor
muscle of the forearm,
and is the direct antago-
nist of the biceps.
The muscles covering
the forearm are disposed
in groups, the pronators
and flexors being placed
on the front and inner
part of the forearm, and
the supinators and exten-
sors on the outer side and
back of the forearm : they
antagonize one another.
The pronators turn the
palm of the hand down-
wards or prone, the supi-
nators turn it upwards or
supine. The flexors and
extensors have long ten-
dons, some of which are
inserted into the bones of
the wrist, and some into
the bones of the fingers :
they serve to flex and ex-
tend the wrist and fingers.
Muscles of the lower ex-
tremity. — These include
FIG. 60. — MUSCLES OF THE THIGH. 46, glu- the muscles of hip, thigh,
teus maximus ; 36, 35, posterior femoral; 33, sar- , , , T1 .
torius ; 27, 26, internal femoral or adductor. leg> ancl ot'
prominent of these are : —
Glutei or gluteal muscles.
Posterior femoral.
Anterior femoral.
Internal femoral.
Tibialis anticus.
Extensors.
Peroneal.
Gastrocnemius.
Soleus.
Flexors.
Tibialis posticus.
CHAP. VI.]
THE MUSCLES.
69
If we compare the muscles of the
shoulder and arm with those of the
hip and leg, we shall see that the an-
terior muscles of the former corre-
spond roughly with the posterior
muscles of the latter, the muscles of
the hip and leg, however, being
larger and coarser in texture than
those of the shoulder and arm.
The glutei, or three gluteal mus-
cles, form the chief prominence of
the buttocks. They are coarse in
texture, and are powerful abductors
of the thigh; but the chief action
of the largest of these three muscles,
the gluteus maximus, is to bring the
body into the erect posture when the
trunk is bent forwards upon the
thigh. It also comes into operation
in ascending stairs, in leaping, and
in rising from the sitting posture.
The posterior femoral or hamstring
muscles cover the back of the thigh.
There are three of these muscles,
— the biceps, the semitendinosus,
and the semimembranosus. The
chief of these is the biceps, and is
somewhat analogous to the biceps
covering the front of the arm. The
action of the hamstring muscles is
to flex the knee and to extend the
hip.
The anterior femoral muscles are
the quadriceps and sartorius. The
quadriceps covers the front of the
thigh, and is analogous to the triceps
covering the back of the arm ; it is
• i f ,1 •> •, FIG. 61. — MuBCLtt OF LBG. Su-
the great extensor of the leg; it PERFICIAL VJKW OF THK CALF.
also flexes the hip, and antagonizes 22, temio Achiiiis: 21, gastrocne-
,, ,. ,, , , , . , mius; 18, soleus; 16, peroueal mus-
the action of the hamstring muscles. cleSt
70 ANATOMY FOR NURSES. [CHAP. VI.
The sartorius, or tailor's muscle, is a long, ribbon-like muscle,
the longest in the body: it crosses the thigh obliquely from
its origin in the ilium to its insertion in the tibia. It is supposed
to be the muscle principally concerned in producing the posture
assumed by the tailor in sitting cross-legged, and hence its name.
The internal femoral or adductor muscles occupy the internal
portion of the thigh : they are all adductors of the thigh.
The tibialis anticus, the extensors, and the peroneal muscles
cover the front and outer side of the leg. The gastrocnemius
and the soleus, the flexors, and the tibialis posticus, cover the back
of the leg. The action of the tibialis anticus and of one of the
three peroneal muscles is to flex the ankle, while the action of
the tibialis posticus and the other peroneal muscles is to extend
the ankle. The flexors and extensors act on the toes.
The gastrocnemius and soleus form the calf of the leg; they
are inserted into a common tendon, the tendo Achillis, which is
the thickest and strongest tendon in the body, and is inserted
into the os calcis, or heel bone. The muscles of the calf possess
considerable power, and are constantly called into use in stand-
ing, walking, dancing, and leaping ; hence the large size they
usually present.
The sole of the foot is protected by a fascia, called the plantar
fascia, which is very strong, and the densest of all the fibrous
membranes.
Most of the muscles are covered closely by sheets of fibrous
connective tissue (fasciae), and this deep layer of tissue forms a
nearly continuous covering beneath the superficial or subcu-
taneous layer of areolar connective tissue, which in a former
chapter we saw to be continuous over the whole of the body.
Parts of the deep fasciae in the vicinity of the larger' joints, as
at the wrist and ankle, become blended into tight transverse
bands which serve to hold the tendons close to the bones, and
receive the name of annular ligaments.
CHAP. VI.]
THE MUSCLES.
71
TABLE OF tJHIEF MUSCLES.
Occipito-frontalis. HEAD.
Temporal. -)
Masseter. [ Muscles of Mastication.
Pterygoid. J
Exterior rectus.
Interior rectus.
Superior rectus.
Inferior rectus.
Superior oblique.
Inferior oblique.
Genio-glossus. 1
Stylo-glossus. J
Stern o-cleido-mastoid.
Muscles of the Eye.
FACE.
TONGUE.
NECK.
Intercostals.
Subcostals.
Levatores costarum.
Pectoral major.
Pectoral minor.
THORAX.
Diaphragm. BETWEEN THORAX AND ABDOMEN.
Obliquus externus abdominis. ~)
Obliquus intern us abdominis.
}• ABDOMEN.
Transversalis abdominis.
Rectus abdominis.
Trapezius. 1 „
, . [BACK.
Latissimus dorsi. J
Deltoid. SHOULDER.
Biceps flexor cubiti. 1 .
Triceps extensor cubiti. J
Pronators (2).
Supinators (2).
Flexors of the wrist (2).
Flexors of fingers and thumb (3)
Extensors of wrist (3).
Extensors of fingers and thumb (6).
FOREARM.
( Maximus.
Gluteij Medius/
I Minimus.
HIP.
72
ANATOMY FOE NURSES.
[CHAP. VL
r Biceps flexor cruris.
Posterior femoral J Semitendinolus.
I Semimembranosus.
Anterior femoral { QuadricePs exteisor cruris.
[ Sartorms.
{Adductor longus.
Adductor brevis.
Adductor magnus.
Tibialis anticus.
Tibialis posticus.
Peroneal (3).
Gastrocnemius. !• LEG.
Soleus.
Flexors of toes (4).
Extensors of toes (4). >
THIGH.
CHAPTER VII.
THE VASCULAR SYSTEM: THE BLOOD.
HAVING studied three of the distinctive tissues of the body
(the epithelial, connective, and muscular), their structure, posi-
tion in the body, and the various functions they are especially
adapted to perform, we shall next consider the vascular, respi-
ratory, alimentary, and excretory systems, by means of which
all the tissues are supplied with the materials necessary for their
life and growth, and relieved of all those waste and superfluous
matters which are the results of their activity.1
All the tissues of the body are traversed by minute tubes,
called capillary blood-vessels, to which blood is brought by
large tubes, called arteries, and from which blood is carried
away by other large tubes, called veins. These capillaries form
networks, the meshes of which differ in form and size in the
different tissues. The meshes of these networks are occupied
by the elements (cells or fibres) of the tissues ; and filling up
such spaces as exist between the capillary walls and the ele-
ments of the tissue, is found a colourless fluid, resembling in
many respects the fluid portion of the blood, and called lymph.
As the blood flows through the capillaries, certain constituents
of the blood pass through the capillary wall into the lymph,
and certain constituents of the lymph pass through the capillary
wall into the blood within the capillary. There is thus an
interchange of material between the blood within the capillary
and the lymph outside. A similar interchange of material is at
the same time going on between the lymph and the tissue itself.
1 As the nervous tissue is the most highly organized of the tissues, and its
functions are very complex and difficult to understand, the consideration of it is
deferred until the student has mastered the vascular, respiratory, alimentary,
and excretory systems.
73
74 ANATOMY FOR NURSES. [CHAP. VII.
Hence, by means of the lymph acting as middleman, a double
interchange of material takes place between the blood within
the capillary and the tissue outside the capillary. In every
tissue, so long as life lasts and the blood flows through the
blood-vessels, a fluid is passing from the blood to the tissue, and
from the tissue to the blood. The fluid from the blood to the
tissue carries to the tissue the material which the tissue needs
for building itself up and for doing its work, including the
all-important oxygen. The fluid from the tissue to the blood
carries into the blood certain of the products of the chemical
changes which have been taking place in the tissue — products
which may be simply waste, to be cast out of the body as soon
as possible, or which. may be bodies capable of being made use
of by some other tissue. The tissues, by the help of the lymph,
live on the blood, and the blood may thus be regarded as an
internal medium, bearing the same relations to the tissue that
the external medium, the world, does to the whole individual.
Just as the whole organism lives on the things around it, its
air and its food, so the several tissues live on the complex fluid
by which they are all bathed, and which is to them their imme-
diate air and food.
The blood. — The most striking external feature of the blood
is its well-known colour, which is bright red approaching to
scarlet in the arteries, but of a dark-red or purple tint in the
veins. It is a somewhat sticky liquid, a little heavier than
water, its specific gravity being about 1.055 ; it has a saltish
taste, a slight alkaline reaction, and a temperature of about
100° F.
Seen with the naked eye the blood appears opaque and homo-
geneous ; but when examined with a microscope it is seen to
consist of a transparent, colourless fluid, with minute solid par-
ticles immersed in it. The colourless fluid is named plasma
the solid particles corpuscles. These corpuscles are of two
kinds, the red or coloured, and the white or colourless. In
a cubic millimetre 1 of healthy blood there are on an average
5,000,000 red corpuscles, and 10,000 white. The number of
white varies much more than that of the red ; the proportion
of white to the red is usually given at from 1 to 250 up to
1 to 1000.
1 A millimetre is equal to 0.039, or ^ of an English inch.
CHAP. VII.] THE VASCULAR SYSTEM.
of biconcave disks.
average size is
Red corpuscles of the blood. — The red corpuscles have a nearly
circular outline like a piece of coin, and most of them have a shal-
low, dimple-like depres-
sion on both sides ; their
shape is, therefore, that
The
of
an inch in diameter, and
about one-fourth that
in thickness. When
viewed singly by trans-
mitted light the col-
oured corpuscles do not
appear red, but merely of
a reddish-yellow tinge,
or yellowish-green in
venous blood. It is only
when the light shines FIG. 62. - RED AND WHITE CORPUSCLES OK
Upon a number of COr- THE BLOOD- Magnified. A, moderately magnified,
, , ... the red corpuscles are seen in rouleaux; a, a,
pUSCleS that a distinct white corpuscles; B, C, D, red corpuscles, highly
red colour is produced. ma»nined» seen m different positions ; E, a red cor-
puscle swollen into a sphere by imbibition of water;
F, G, white corpuscles, highly magnified ; K, white
When blood is drawn
from the vessels, the red corPuscle treated with acetic acid; * i> «*i COP-
puscles wrinkled or creuated.
disks sink in the plasma:
they have a singular tendency to run together, and to cohere
by their broad surfaces, so as to form cylindrical columns like
piles or rouleaux of coins, and the piles join themselves together
in an irregular network. Generally the corpuscles separate on
a slight impulse, and may then unite again.
Each red corpuscle is composed of an external colour/ess enve-
lope with coloured fluid contents. — Quain.
The envelope is a very delicate membrane of a fatty nature,
and may be ruptured or dissolved under certain conditions.
The colour of the fluid contents is due to a crystallizable sub-
stance called haemoglobin.1 If water be added to a preparation
of blood under the microscope, the water passes into the cor-
puscle, and the concave sides of the corpuscle become bulged
out so that it is rendered globular. By the further action of
1 Haemoglobin is a proteid, and contains, in addition to the usual proteid
elements, a certain amount of iron.
76 ANATOMY FOE NURSES. [CHAP. VIL
water the haemoglobin is dissolved out of the corpuscle, and
the colourless envelope remains as a faint circular outline. On
the other hand, the addition of salt to a preparation of blood by
absorbing the water causes the corpuscles to shrink, and become
wrinkled or crenated. The red corpuscles are practically small
flattened bags, or sacs, the form of which may be changed by
altering the density of the plasma. They are very soft, flexible,
and elastic, so that they readily squeeze through apertures and
passages narrower than their own diameters, and immediately
resume their proper shape.
Function of the red corpuscles. — The red corpuscles, by virtue
of their haemoglobin, are emphatically oxygen carriers. Ex-
posed to the air in the lungs, the haemoglobin combines with
the oxygen present in the air; this oxygen the haemoglobin
carries to the tissues ; these, more greedy of oxygen than itself,
rob it of its charge, and the reduced haemoglobin hurries back
to the lungs for a fresh supply. The colour of the blood is
dependent upon this combination of the haemoglobin with oxy-
gen ; when the haemoglobin has its full complement of oxygen,
the blood has a bright red hue ; when the amount is reduced, it
changes to a dark purplish hue. The scarlet blood is usually
found in the arteries, and is called arterial; the dark purple
in the veins, and is called venous blood.
White corpuscles of the blood. — The white, colourless corpus-
cles, or leucocytes, are few in number compared with the red,
and both on this account, and because of their want of colour,
they are not at first easily recognized in a microscopic prepara-
tion of blood. Their form is very various, but when the blood
is first drawn they are rounded or spheroidal. Measured in this
condition they are about ^Q-Q- of an inch in diameter. The
white corpuscle may be taken as the type of a free animal cell.
It is a small piece of protoplasm, containing one or more nuclei,
and has no limiting membrane or cell-wall (vide Fig. 61 F. G.).
These corpuscles, or cells, possess the power of spontaneous
movement, and are capable of changing their form and place.
While, when in a state of rest, they assume in general the
spheroidal form, we find that when they become active they
send out variously shaped processes, some fine and delicate,
others broad, and of very irregular shape. We often see, after
a process has been thrown out, that it becomes larger and
CHAP. VII.] THE VASCULAK SYSTEM. 77
larger, the cell body becoming correspondingly smaller, until
finally the whole cell passes over into the process, thus moving
forward. These amoeboid movements are always very slow,
and are greatly influenced by the temperature, density, and
amount of oxygen in the fluid in which the cells lie. By virtue
of this locomotive power the white blood cells perform certain
evolutions within the blood-vessels ; they escape through their
walls, and sometimes singly, sometimes in vast numbers, move
through the lymph spaces in the surrounding tissues. This is
spoken of as the " migration of the white corpuscles." In an
"inflamed area" large numbers of white corpuscles are thus
drained away from the blood. These migrating corpuscles, or
wander cells, may, by following the devious tracks of the lymph,
find their way back into the blood; some of them, however,
may remain and undergo various changes. Thus in inflamed
areas, when suppuration follows inflammation, the white cor-
puscles which have migrated may become " pus corpuscles."
Again, by virtue of their amoeboid movements, the white
corpuscles can creep around objects, enveloping them with their
own substance, and so putting them inside themselves. As an
illustration of this action of the white corpuscle, we may state
that, according to some observers in certain diseases in which
micro-organisms make their appearance in the blood, the white
corpuscles take up these organisms into their substance and
probably exert an influence over them, which modifies the
course of the disease of which these organisms are the essen-
tial cause.
Furthermore, the white corpuscles are not only capable of
taking up particles in the blood, but are also capable of giving
up modified products to the blood, and it follows that these
metabolic changes must necessarily affect the composition of the
fluid plasma in which they lie.
The plasma of the blood. — The plasma is a clear, slightly
yellowish coloured fluid, consisting for the most part of water,
holding in solution or suspension proteid substances, fats,
various extractives, and saline matters.
The proteid substances are albumin, para-globulin, and fibrin-
ogen. The albumin and para-globulin occur in about equal
quantities; but the fibrinogen, though a most important element
in the blood, occurs in very small quantities. The fats are
78 ANATOMY FOR NUESES. [CHAP. V1L
scanty, except after a meal, or in certain diseased conditions.
The extractives, so named because they have to be extracted by
special methods from the blood, are very numerous. The most
important are perhaps urea, lactic acid, and sugar.
The saline matters are the chlorides and sodium salts, the
phosphates and potassium salts being found chiefly in the
corpuscles.
Of all these substances, albumin probably holds the first place
in regard to nutrition, providing, as it does, the greater part of
the material necessary for the daily nourishment and renovation
of the tissues. In this process, it undergoes a variety of trans-
formations by which it is converted into the structural charac-
teristics of the tissues which it supplies.
Para-globulin is closely allied to albumin in its chemical rela-
tions, and no doubt also in its physiological action. Both sub-
stances are coagulated by heat, and solidified at a temperature
of 160° F.
The fibrinogen of the plasma is the substance which produces
the fibrin of coagulated blood. It is very difficult to obtain
in the fluid condition, owing to the rapidity with which it
solidifies when blood is withdrawn from the circulation.
Of the mineral salts, the sodium chloride is the most abun-
dant, constituting nearly 40 per cent of all the saline ingredi-
ents. The mineral salts maintain the alkalescence of the blood,
a property which is essential to nutrition, and even to the
immediate continuance of life, since it enables the plasma to
take up the carbonic acid from the tissues and return it to the
lungs for elimination.
The clotting of blood. — Blood when drawn from the blood-
vessels of a living body is perfectly fluid. In a short time it
becomes viscid, and this viscidity increases rapidly until the
whole mass of blood becomes a complete jelly. If the blood in
this jelly stage be left untouched in a glass vessel, a few drops
of an almost colourless fluid soon make their appearance on the
surface of the jelly. Increasing in number and running together,
the drops after a while form a superficial layer of pale straw-
coloured fluid. Later on, similar layers of the same fluid are
seen at the sides, and finally at the bottom of the jelly, which,
shrunk to a smaller size and of firmer consistency, now forms a
clot or crassamentum, floating in a perfectly fluid liquid. The
CHAP. VIL] THE VASCULAR SYSTEM. 79
upper surface of the clot is generally slightly concave. If a
portion of the clot be examined under the microscope, it is seen
to consist of a network of fine fibrils in the meshes of which
are entangled the red and white corpuscles of the blood. The
fibrils are composed of the fibrin; and the liquid in which
the clot is suspended is blood minus corpuscles and fibrin, and
is called serum. The clotting of the blood is entirely dependent
upon the fibrin ; for if fresh blood, before it has time to clot, be
whipped with a bundle of twigs, the fibrin will form on the
twigs, and if the whipping of the blood be continued until all
the fibrin has been deposited on the twigs, the blood left in the
vessel will be found to have lost all power of clotting.
The coagulation of blood is hastened by high temperature,
and by contact with any rough surface, or non-living material.
On the other hand, a low temperature retards, and the addition
of salt in sufficient quantity prevents, coagulation. After death,
the blood remains a long time fluid, and it never clots so firmly
and completely as when shed. It clots first in the larger vessels,
but not until several hours after death in the smaller vessels.
The coagulability of the blood differs in different individuals,
and in rare cases is so slight that the most trivial operation in-
volving hemorrhage is attended with great danger.
The quantity of blood contained in the body is a balance
struck between the tissues which give to, and those which take
away from, the blood. Thus the tissues of the alimentary canal
largely add to the blood water and the material derived from
food, while the excretory organs largely take away water and
the other substances constituting the excretions. From the
result of a few observations on executed criminals, it has been
concluded that the total quantity of blood in the human body is
about Jg- of the body weight.
General composition of the blood. — Not only do the several tis-
sues take up from the blood and give up to the blood different
things at different rates and at different times, but all the
tissues take up oxygen and give up carbonic acid in varying
quantities. From this it follows, on the one hand, that the
composition and character of the blood must be forever varying
in different parts of the body ; and, on the other hand, that the
united action of all the tissues must tend to establish and main-
tain an average uniform composition of the whole mass of blood.
80 ANATOMY FOR NURSES. [CHAP. VII.
To sum up briefly, the blood is composed of —
Proteid substances.
Fats.
PLASMA • •«,
Extractives.
Salts.
rRed
CORPUSCLES j and
I White.
The plasma is chiefly the carrier of nutriment to the tissues,
and of waste matter from the tissues. The red corpuscles are
pre-eminently the carriers of oxygen ; the white corpuscles may
be regarded as scavengers, as important protective elements in
many diseases, and possibly as contributors to the construction
of new tissue where such has been injured or destroyed.
NOTE. — When we remember that the tissues live on the blood, we recognize
the gravity of those diseased conditions in which important elements are being
constantly drained away from the blood, as, for example, the albumin in dis-
eases of the kidneys, the red corpuscles in hemorrhage, the water of the blood
in cholera, etc. Withdrawal of oxygen, as we all know, causes instant death,
and a constant supply of fresh air is a vital necessity of life. Nor is it of less
importance that the blood be kept free from those waste matters, — pre-eminently
carbonic acid and urea, — which, in accumulating, poison the system, and, if
not excreted in sufficient amount, will as surely cause death as the withdrawal
from the blood of any of its most vital constituents.
CHAPTER VIII.
THE VASCULAR SYSTEM CONTINUED: HEART; ARTERIES;
VEINS; CAPILLARIES.
THE blood, as we have said, is the internal medium on which
the tissues live. It is carried through the body by branched
tubes named blood-vessels. It is driven along these tubes by
the action of the heart, which is a hollow muscular organ placed
in the centre of the vascular system. One set of vessels — the
arteries — conducts the blood out from the heart and distributes
it to the different parts of the body, whilst other vessels — the
veins — bring it back to the heart again. The blood from the
arteries gets into the veins by passing through a network of
fine tubes which connect the two, and which are named, on
account of their small size, the capillary (i.e. hair-like) vessels.
All the tissues, with the exception of the epithelial tissue,
and most of the cartilages, are traversed by these networks of
capillary vessels. It is through the thin walls of the capillaries
that the interchange of material which is continually going on
between the blood and the tissues takes place. It is in the
capillaries, then, that the chief work of the blood is done ; and
the object of the vascular mechanism is to cause the blood to
flow through these vessels in the manner best adapted for
accomplishing this work.
The use of the arteries is to carry and regulate the supply of
blood from the heart to the capillaries ; the use of the veins, to
carry the blood from the capillaries back to the heart ; the use
of the heart, to drive the blood in a suitable manner through
the arteries into the capillaries, and from the capillaries back
along the veins to itself again. We shall see that the structure
of these several parts is adapted to these several uses.
The heart. — The heart is a hollow muscular organ, divided
G 81
82
ANATOMY FOE, NUKSES. [CHAP. VIII.
by a longitudinal partition into a right and a left heart, each of
which is subdivided by a transverse constriction into two com-
partments, an upper and a lower, which communicate with each
other. Its general form
is that of a blunt cone.
It is situated in the
thorax, between the
lungs, and, together
with the adjacent parts
of the great blood-ves-
sels which carry blood
to and from it, is en-
closed in a membranous
covering, the pericar-
dium. The heart lies
nearer to the front
than to the back of the
chest, and is placed be-
FIG. 63. — THE HEART AND LUNGS. 1, right ven- , . , , ,
tricle; 3, right auricle; 6, 7, pulmonary artery; 9, nmd
aorta; 10, superior vena cava; 11, innominate ar-
tery ; 12, right subclavian vein ; 14, innominate vein ;
15, left common carotid; 17, trachea; 20, pulmonary
veins ; 22 to 25, lungs, partially turned back to show "base bein Q directed UD-
veins on left side.
wards, backwards, and
to the right, while the pointed end or apex points downwards,
forwards, and to the left. The impulse of the heart against the
wall of the chest is felt in the space between the fifth and sixth
ribs, a little below and to the inner side of the left nipple. It
has, therefore, a very oblique position in the chest. It is sus-
pended and kept in position by the great vessels at the base,
and is also supported by the diaphragm. According to Laennec,
the heart in its normal condition is about equal in size to the
fist of the individual to whom it belongs.
The main substance of the heart is composed of muscular
tissue. Between the muscle fibres is a certain amount of in-
terstitial tissue with numerous blood-vessels and lymphatics,
and, in some parts, nerves and ganglia. There is also a consid-
erable amount of fat, chiefly collected at the base of the heart
and beneath the pericardium. The muscular tissue of the heart
differs from all other involuntary muscular tissue in possessing
transverse striae. The fibres continually branch and unite with
costal cartilages,
broader end or
CHAP. VIII.] THE VASCULAK SYSTEM.
83
one another so as to form a kind of network or sponge-like sub-
stance. The arrangement of the fibres differs in the auricles
and the ventricles, and is very intricate ; the fibres run trans-
versely, longitudinally, obliquely, and in the apex of the ven-
tricles take a spiral turn
or twist. The muscular
walls of the auricles are
much thinner than those
of the ventricles, and the
wall of the left ventricle
is thicker than that of the
right. This difference in
bulk is to be accounted
for, as we shall see later
on, by the greater amount
of work the ventricles, as
compared with the auri-
cles, have to do. The
muscular walls of the
heart are abundantly
supplied with blood
and lymph. The nerves FIG. 64. — ANTERIOR VIEW OF HEART, DIS-
whioh mirmlv thp hpart SECTED> AFTER LONG BOILING, TO SHOW THE
>uppiy G SUPERFICIAL MUSCULAR FIBRES. (Allen Thorn-
are partly derived from son.) The aorta (&') and pulmonary artery (a')
,1 i • i have been cut short close to the semilunar valves.
the cerebro-spmal system, a> right ventricle. 6> left ventricie: c,c, groove
and partly from the Sym- between ventricles ; d, d', right auricle ; e, e', left
,| ,. p auricle; /, superior vena cava; g', g", right and
patnetl System. l^On- ]eft pUimonary veins. The fibres are seen run-
nected with the lierve niuS in a circular, oblique, transverse, and longi-
^., , . , tudinal direction.
fibres supplying the heart
are groups of nerve cells, or ganglia.
The heart is covered, as mentioned above, by a membranous
covering in the form of a sac. This membranous sac, or peri-
cardium, is one of the serous membranes of the body.1 It is a
sort of double bag ; one half of the bag, called the visceral por-
tion (viscus, organ), is closely adherent to the heart substance,
and also covers the great blood-vessels for about an inch and a
half from the base of the heart ; the other half, the parietal
portion, is continuous with, and reflected over, the visceral por-
tion, so that it loosely envelops both it and the heart.
1 See note on serous membranes at end of chapter.
84 ANATOMY FOR NURSES. [CHAP. VIII.
The pericardium forms a completely closed sac ; its internal
surfaces are very smooth and polished, they are lined by epithe-
lium, and secrete a small quantity of serous fluid. As their
opposing surfaces, owing to the constant contractions of the
heart, are continually sliding one upon the other, they are ad-
mirably constructed to protect the heart from any loss of power
by friction.
The interior of the heart is lined by a delicate, smooth mem-
brane, called the endocardium. This pavement membrane lines
all the cavities of the heart, and is continued into the blood-
vessels, forming their innermost coat.
The cavities of the heart. — The heart is divided from the base
to the apex, by a fixed partition, into a right and left half.
The two sides of the heart
have no communication with
each other: the right side al-
ways contains venous, and the
left side arterial, blood. Each
half is subdivided into two
cavities, the upper, called au-
ricle ; the lower, ventricle.
These cavities communicate
with one another by means of
constricted openings, the auric-
ulo-ventricular orifices, which
are strengthened by fibrous
FIG. 65. -RIGHT 'SIDE OF HEA^ i, rings, and protected and guard-
cavity of right auricle ; 3, vena cava supe- ed by valves. The valve guard-
rior; 4, vena cava inferior; 9, entrance of ,• • i j i , •
auriculo-ventricular opening ;«, right ven- mg the nght aunculo,ventriC-
tricle; 6, c, cavity of right ventricle, on ular opening is Composed of
the walls of which the columnse carnse ,-t , • -, n , .
are seen; d, pulmonary artery; e, /, tri- three triangular flaps, and IS
cuspid valve; z,columnae carnse; m, semi- hence named tricuspid. The
lunar val ve ; o, left ventricle; p, ascending n . , ~
aorta; q, arch; r, descending aorta. naPs are mainly formed of
fibrous tissue covered by endo-
cardium. At their bases they are continuous with one another,
and form a ring-shaped membrane around the margin of the auric-
ular opening : their pointed ends are directed downwards, and
are attached by cords, the chordce tendinece, to little muscular
pillars provided in the interior of the ventricles for this purpose.
The valve guarding the left auricular opening consists of only
CHAP. VIII.] THE VASCULAR SYSTEM.
85
FIG. 66. — LEFT SIDE OF HEART. 1, cavity
drives the flaps backwards of left auricle; 3' opening of right
two flaps, and is named the bicuspid, or mitral valve. It is
attached in the same manner as the tricuspid valve, which it close-
ly resembles in structure,
except that it is much
stronger and thicker in
all its parts.
These valves oppose no
obstacle to the passage of
the blood from the auri-
cles into the ventricles ;
but any flow forced back-
wards gets behind the
flaps of the valve (be-
tween the flap and the
wall of the ventricle) and
veins ; 5, left pulmonary veins ; 6, auriculo-ven-
and Upwards, Until, meet- tricular opening; 8, left ventricle; 9,9, cavity of
, , left ventricle; a, mitral valve, its flaps are at-
ing at their edges, tney tached by the chorda? tendinese to b, b, the mus-
Ullite and form a com- cu^ar pillars, or colunmae carnse ; d, arch of aorta;
e, pulmonary artery.
plete transverse partition
between the ventricle and auricle. Being retained by the
chordae tendinese, the expanded flaps of the valve resist any
pressure of the blood
which might otherwise
force them back to open
into the auricle ; the mus
cular pillars, also, to
which the chordae tendi-
neae are attached, contract
and shorten at the same
time, and thus help to
keep them taut.
Beside the openings be-
tween the auricles and
ventricles, each auricle
has two or more veins
opening into it, and each
ventricle has a large ar-
tery opening out of it.
The openings of the veins do not require valves, but both the
FIG. 67. — SECTION OF HEART AT LEVEL OF
VALVES. P, pulmonary artery; A, aorta; M,
mitral valve ; T, tricuspid valve.
86 ANATOMY FOR NURSES. [CHAP. VIII.
arterial openings are provided with a set of valves. These valves,
called semilunar valves, consist of three semicircular flaps, each
flap being attached by its convex border to the inside of the
artery where it joins the ventricle, while its other border projects
into the interior of the vessel. The flaps of these valves form a
complete barrier, when closed, to the passage of the blood from
the arteries into the heart, but offer no resistance to the flow
from the heart into the arteries.
The beat of the heart. — So long as life lasts, the muscular
tissue of the heart contracts and relaxes unceasingly. We may
call the heart a muscular pump, the force of whose strokes is
supplied by the contraction of muscular fibres, the strokes
being repeated so many times a minute. It is constructed and
furnished with valves in such a way that, at each stroke, it
drives a certain quantity of blood with a certain force and a
certain rapidity from the ventricles into the arteries, receiving,
during the stroke, and the interval between that stroke and
the next, the same quantity of blood from the veins into
the auricles.
The contractions of the heart are rhythmical ; that is to say,
they occur in a certain order. First, there is a simultaneous
contraction of the walls of both auricles ; immediately following
this, a simultaneous contraction of both ventricles ; then comes
a pause, or period of rest, after which the auricles and ven-
tricles contract again in the same order as before, and their
contractions are followed by the same pause as before. The
state of contraction of the heart is called the systole ; the state
of relaxation and dilatation, its diastole.
If the chest of an animal be opened and artificial respiration
kept up, the heart may be watched beating, and a complete beat
of the whole heart may be observed to take place as follows : —
The great veins are seen, while full of blood, to contract in
the neighbourhood of the heart, the wave of contraction running
on towards the auricles, increasing in intensity as it goes.
Arrived at the auricles, which are now full of blood, the wave
of contraction passes on to them, and they contract suddenly
and quickly. During this contraction, the walls of the auricles
press towards the auriculo-ventricular orifices, and the blood
passes over the tricuspid and mitral valves into the ventricles.
The ventricles fill rapidly, and as soon as the auricular systole
CHAP. VIII.] THE VASCULAR SYSTEM. 87
is over, they are also seen to contract, their walls becoming very
tense and hard; the apex is tilted upwards, and the heart
twists somewhat on its own axis. During the ventricular
systole, the blood in the ventricles is forced through the semi-
lunar valves into the arteries, which are seen to elongate and
expand as the blood is pumped into them.
The work of the auricles and ventricles is very unequal.
All the auricles have to do is to pump the blood into the ven-
tricles, which at the time are nearly empty cavities with relaxed
and flaccid walls. The ventricles, on the contrary, have to
pump the blood into tubes which are already full ; and if there
were no auriculo-ventricular valves, the blood would meet with
less resistance in pushing its way backward into the auricles
than in pushing open the semilunar valves and forcing its way
into the arteries.
Hence the necessity, firstly, of the tricuspid and mitral
valves; and, secondly, of the superior thickness and strength
of the walls of the ventricles, as compared with those of the
auricles; and since the left side of the heart has a larger
system of blood-vessels to supply, and more resistance to over-
come than the right side, it follows that the left ventricle needs
a thicker muscular wall than the right.
The beat of the heart is caused by the rhythmical contractions
of its muscular fibres. Whether these contractions are auto-
matic, or dependent upon the ganglia lodged in the cardiac
muscular tissue, is uncertain. That the contractions of the
heart do not depend upon the general nervous system is cer-
tain, for the heart will continue to beat for some little time
after its removal from the body. It probably depends upon
complex metabolic changes, not yet clearly understood.
The character of the beat, however, is governed and regulated
by two sets of nerves. The first set come from the cerebro-spinal
centre, and are supplied by the pneumogastric nerves. They
are the inhibitory fibres ; that is to say, they slow and, with a
strong stimulation, will stop for a short time the action of tlic
heart. They weaken the systole, and prolong the diastole.
The other set come from the sympathetic nerves, and are accel-
erating fibres which, upon stimulation, increase not only the
rapidity, but the force of the beat. The diastole is shortened,
and the systole strengthened.
88
ANATOMY FOR NURSES. [CHAP. VIII.
The sounds of the heart. — If the ear be applied over the heart,
certain sounds are heard, which recur with great regularity.
The first sound is a comparatively long, booming sound; the
second, a short, sharp, sudden one. Between the first and
second sounds, the interval of time is very short, too short to
be measurable ; but, between the second arid the succeeding first
sounds there is a distinct pause. The first sound is generally
supposed to be caused by the contraction of the ventricular
walls ; the second sound is undoubtedly caused by the sudden
closure of the semilunar valves.
These sounds in certain diseases of the heart become changed
and obscure, and are replaced by various distinctive and charac-
teristic murmurs.
The arteries. — An artery is usually described as being com-
posed of three coats, — an inner or
elastic, a middle or muscular, and
an external or areolar.
The inner coat of an artery con-
sists of two layers : the inner layer
is composed of pavement epithe-
lium, and forms a smooth lining for
the tube ; the outer layer is a fine
network of elastic connective tissue
fibres.
The middle or muscular coat con-
sists mainly of circularly disposed
plain muscular fibres. It has also
FIG. 68. — STRUCTURE OF AN • , -, ^ <• i
ARTERY. (Ledig.) A, internal m most large arteries layers of elas-
coat, with b, its inner layer of tic fibres, which form close felted
pavement epithelium; c, middle 1^.1^1 _<• ,1
coat, with transverse fibres; a, networks, the fibres running for the
outer coat, with longitudinal mOst part in an oblique and longitu^
fibres. .*:.
dmal direction.
The outer coat is formed of areolar tissue, mixed with which
are a good many elastic fibres. The strength of an artery
depends largely upon this coat ; it is far less easily cut or torn
than the other coats, and it serves to resist undue expansion of
the vessel. The arteries are also protected by sheaths of con-
nective tissue, which surround and blend with the outer coat.
By virtue of their structure, the arteries are both contractile
and elastic. The proportion of the muscular and elastic ele-
CHAP. VIII.] THE VASCULAR SYSTEM. 89
ments differs in different arteries ; but, as a general rule, the
larger arteries are the more elastic, and the smaller the more
muscular. The elasticity and contractility of the arteries may
be demonstrated by the following example : -
If we tie a piece of a large artery at one end and inject fluid
into the other end, the artery swells out to a very great extent,
but will return at once to its former size when the fluid is let
out. This great elasticity of the arteries adapts them for
receiving the additional amount of blood thrown into them
at each contraction of the heart. Again, if we stimulate the
muscular coat of any of the smaller arteries, the artery will
shrink in size, the circularly disposed fibres contracting and
narrowing the calibre of the vessel. This contractility is under
the control of the nervous system, and as the organs of the
body that are at rest do not require so much blood as those that
are working actively, the nervous system, the master-regulator
of the body's work, is able to diminish or increase the supply of
blood to the capillaries in different parts by acting upon this
contractile muscular tissue in the arterial walls. The arteries
do not collapse when empty; and when an artery is severed,
the orifice remains open. The muscular coat, however, con-
tracts somewhat in the neighbourhood of the opening, and the
elastic fibres cause the artery to retract a little within its
sheath.1
The walls of the arteries are supplied with both blood-vessels
and nerves. The blood-vessels are known as the vaso-vasorum
vessels and the nerves as the vaso-motor nerves.
The veins. — The veins have three coats, and on the whole
resemble the arteries in structure. They differ from them,
however, in having much thinner walls, and in their walls con-
taining relatively much more white fibrous tissue and much less
yellow elastic tissue., They are, therefore, not so elastic or con-
tractile as the arteries, and their walls collapse when empty.
Many of the veins, especially those of the limbs, are provided
with valves, which are mechanical contrivances adapted to pre-
vent the reflux of the blood. The valves are semilunar folds of
the internal coat of the veins ; the convex border is attached to
the side of the vein, and the free edge points towards the heart.
1 This property of the severed artery is an important factor in the arrest of
hemorrhage.
90 ANATOMY FOR NURSES. [CHAP. VIII.
Should the blood in its onward course towards the heart be, for
any reason, driven backwards, the refluent blood, getting be-
tween the wall of the vein and the flaps of
the valve, will press them inwards until
their edges meet in the middle of the chan-
nel and close it up. The valves have
usually two flaps, sometimes one, and
rarely three. The veins, like the arteries,
are supplied with both blood-vessels and
nerves, the supply, however, being far less
abundant.
The capillaries. — The walls of the cap-
illaries are formed entirely of a layer of
pairs of valves; B, longi- simple epithelium composed of flattened
tudinal section of vein, ,, . . , 1 11 u
showing valves closed. cells joined edge to edge by cement sub-
stance, and continuous with the layer
which lines the arteries and veins. The capillaries commu-
nicate freely with one another and form interlacing networks
of variable form and size in the different tissues. Their
average diameter is so small that only two or three blood-
corpuscles can pass through them abreast, and in many parts
they lie so closely together that a pin's point cannot be in-
serted between them. They are most abundant, and form the
finest networks in those organs where the blood is needed for
other purposes than local nutrition, such as, for example, for
secretion or absorption. In the glandular organs they supply
the substances requisite for secretion; in the intestines they
take up the elements of digested food ; in the lungs they absorb
oxygen and give up carbonic acid ; in the kidneys they discharge
the waste products collected from other parts ; all the time, every-
where through their walls, that interchange is going on which is
essential to the renovation, growth, and life of the whole body.
It must be remembered that although the arteries, veins, and
capillaries have each the distinctive structure above described,
it is at the same time difficult to draw the line between the
smaller artery and larger capillary, and between the larger
capillary and smallest vein. The veins on leaving the capillary
networks only gradually assume their several coats, while the
arteries dispense with their coats in the same imperceptible way
as they approach the capillaries.
CHAP. VI1L] THE VASCULAR SYSTEM.
91
Serous membranes. — Serous membranes are thin and transparent, tol-
erably strong, extensile, and elastic. They are lined on the inner surface by
a simple epithelial layer of flattened cells (endothelium). The surfaces are
moistened by a fluid resembling serum, and from which the membranes
obtain their name of serous membranes. Here and there between the cells
FIG. 70. — PORTION OF ENDOTHELIUM OF PERITONEUM. (Klein.) a, larger cells;
6, smaller ones, with here and there a pseudo-stoma between.
openings are seen, which are of two kinds. The smaller and more numerous
are false openings, and are termed pseudo-stomata ; the larger or true aper-
tures are termed stornata, and open into subjacent lymphatics. The sub-
stance of serous membranes underneath the endothelium is composed of
a network of connective tissue containing a variable amount of white
and elastic fibres. Where the membrane is thick, this ground substance
contains blood-vessels and lymphatics, the lymphatics being exceedingly
abundant.
Serous membranes form closed sacs, one part of which is attached to the
walls of the cavity which it lines, — the parietal portion, — whilst the other
is reflected over the surface of the organ or organs contained in the cavity,
and is named the visceral portion of the membrane. In this way the viscera
are not contained within the sac, but are really placed outside of it, and
some of the organs may receive a complete, while others receive only a par-
tial or scanty investment.
In passing from one part to another the membrane frequently forms
folds, some of which are designated by special names, such as the mesen-
tery, meso-colon, and omentum.
The chief serous membranes are the peritoneum, the largest of all, lining
the cavity of the abdomen ; the two pleurae, lining the chest and covering
the lungs ; the pericardium, covering the heart.
92 ANATOMY FOE, NUKSES. [CHAP. VIII.
The peritoneum in the female is an exception to the rule that serous
membranes are perfectly closed sacs, as it has two openings by which the
Fallopian tubes communicate with its cavity.
The inner surface of a serous membrane is free, smooth, and polished ;
the inner surface of one part is applied to the corresponding inner surface
of some other part, a very small quantity of fluid only being interposed
between the surfaces. The organs situated in a cavity lined by a serous
membrane, being themselves also covered by it, can thus glide easily against
its walls or upon each other, their motions being rendered smoother by the
lubricating fluid.
CHAPTER IX.
THE VASCULAR SYSTEM CONTINUED : ARTERIAL DISTRIBUTION
AND VENOUS RETURN.
The arteries. — The arteries, which carry and regulate the
supply of blood from the heart to the capillaries, are distributed
throughout the body in a systematic manner, and before taking
up the circulation we must try to gain a general idea of this
system of distribution, in order that we may be able to locate
the position of these important vessels. The arteries usually
occupy protected situations, that they may be exposed as little
as possible to accidental injury. As they proceed in their
course they divide into branches, the division taking place in
different ways. An artery may at once resolve itself into two
or more branches, no one of which greatly exceeds the rest in
size ; or it may give off several branches in succession, and still
maintain its character as a trunk. An artery, after a branch
has gone off from it, is smaller than before, but usually con-
tinues uniform in diameter until the next secession. A branch
of an artery is less in diameter than the trunk from which it
springs, but the collective capacity of all the branches into
which an artery divides is greater than the parent vessel. Since
the area of the arterial system increases as its vessels divide, it
is evident that the collective capacity of the smaller vessels
and capillaries must be greater than the collective capacity of
the trunks from which they arise. As the same rule applies to
the veins, it follows that the arterial and venous systems may
be represented, as regards capacity, by two blunt cones whose
apices are at the heart, and whose bases are united in the cap-
illary system. The effect of this arrangement of the circulatory
vessels is to make the blood flow more slowly as it passes
through the more widely distributed vessels, and to accelerate
93
94 ANATOMY FOK NUKSES. [CHAP. IX.
its speed in the larger and less numerous trunks, just as a river
flows more rapidly through its narrow and deep channels, and
lingers in those that are broad and shallow.
The arteries unite at frequent intervals when they are said to
anastomose or inosculate. Such inosculations admit of free
communication between the currents of the blood, tend to pro-
mote equality of distribution and of pressure, and to obviate
the effects of local interruption.
Arteries commonly pursue a tolerably straight course, but in
some parts of the body they are tortuous. They often become
markedly tortuous in old persons as the walls of the arteries
increase in length and size.
In describing the distribution of the arteries we shall first
consider the artery arising from the left ventricle of the heart,
the aorta, and its branches.
The aorta. — The aorta is the main trunk of the arterial sys-
tem. Springing from the left ventricle of the heart, it arches
over the root of the left lung, descends along the vertebral col-
umn, and after passing through the diaphragm into the abdomi-
nal cavity, ends opposite the fourth lumbar vertebra by dividing
into the right and left common iliac arteries. In this course
the aorta forms a continuous single trunk, which gradually
diminishes in size from its commencement to its termination
(from 28 to 17 mm.), and gives off larger or smaller branches
at various points. It may be divided into the ascending aorta,
the short part which is contained in the pericardium ; the arch,
the part extending from the ascending aorta, and forming a
well-marked curve in front of the trachea, and around the root
of the left lung to the border of the fourth dorsal vertebra ;
the descending thoracic aorta, the comparatively straight part
extending to the diaphragm; the abdominal aorta, below the
diaphragm. The ascending aorta gives off two small branches,
the right and left coronary arteries, which supply the substance
of the heart with blood. The arch gives off three large trunks,
the innominate, the left common carotid, and the left subclavian
artery.
The innominate artery arises from the right upper surface of
the arch, ascends obliquely towards the right, until, arriving on
a level with the upper margin of the clavicle, it divides into the
right common carotid and right subclavian arteries. Its usual
length is from one to two inches.
CHAP. IX.]
THE VASCULAR SYSTEM.
The left common carotid arises from the middle of the upper
surface of the arch of the aorta, and the left subclavian arises
from the left upper surface of the arch.
B
15
10
FIGS. 71, 72. — THE AORTA. A, from before ; B, from behind, with the origin of its
principal branches. (R. Quain.) 1, 2, ascending aorta ; 2, 3, arch of aorta ; 4, innomi-
nate artery ; 5, left carotid ; 0, left subclavian ; 7, 7, 7, intercostal and lumbar arteries ;
8, 8, renal arteries; 9, 9, common iliac arteries; 10, middle sacral arteries; 11, one of
the phrenic arteries; +, coeliac axis; 12, gastric; 13, hepatic; 14, splenic artery; 15,
superior mesenteric ; 16, inferior mesenteric : 17, 17; spermatic or ovarian arteries.
96
ANATOMY FOR KUESES.
[CHAP. IX.
The common carotid arteries. — As the left common carotid
arises from the middle of the upper surface of the arch of the
aorta, while the right common carotid arises at the division of
the innominate, the left carotid is an inch or two longer than
the right. They ascend obliquely on either side of the neck
Fia. 73. — THE CAROTID, SUBCLAVIAN, AND AXILLARY ARTERIES. 1, common
carotid artery; 2, internal carotid; 3 and 18, external carotid; 8, facial artery; 22,
subclavian artery ; 28, axillary artery ; 33, commencement of brachial artery.
until, on a level with the upper border of the thyroid cartilage,
" Adam's apple," they divide into two great branches, of which
one, the external carotid, is distributed to the superficial parts of
the head and face, and the other, the internal carotid, to the
brain and eye. At the root of the neck the common carotids
CHAP. IX.]
THE VASCULAR SYSTEM.
97
are separated from each other by only a narrow interval, corre-
sponding with the width of the trachea; but as they ascend
they are separated by a much
larger interval, corresponding with
the breadth of the larynx and
pharynx.
The external carotid has eight
branches, which are distributed
to the throat, tongue, face, and
walls of the cranium.
The chief branches of the in-
ternal carotid are the ophthalmic
and cerebral arteries. A remark-
able anastomosis exists between
the cerebral arteries at the base of
the brain. The arteries are joined
in such a manner as to form a
complete circle, and this anasto-
mosis, known as the " circle of
Willis," both equalizes the circula-
tion of the blood in the brain, and
also provides, in case of destruction
of one of the arteries, for the blood
reaching the brain through the
other vessels.
The subclavian arteries. — The
right subclavian arises at the
division of the innominate, and
the left subclavian from the arch
of the aorta. The subclavian
arteries are the first portions of a
long trunk which forms the main
artery of the upper limb, and which
is artificially divided for purposes
of description into three parts; OF THB ARTERIES OF THE A KM,
viz. the subclavian, axillary, and ^S^^SLSSMS^
bracMal arteries. The Subclavian artery; 6, deep palmar arch; 8, ulnar
artery passes a short way up the artery-
thorax into the neck, and then turns downwards to rest on the
first rib. At the outer border of the first rib it ceases to be called
FIG. 74. — DEEP ANTERIOR VIEW
98 ANATOMY FOE, NUKSES. [CHAP. IX.
subclavian, and is continued as the axillary. It gives off large
branches to the back, chest, and neck.
The axillary artery passes through the axilla, lying to the
inner side of the shoulder joint and upper part of the arm. It
gives off branches to chest, shoulder, and arm.
The brachial artery extends from the axillary space to just
below the bend of the elbow, where it divides into the ulnar and
radial arteries. It may be readily located, lying in the depres-
sion along the inner border of the biceps muscle. Pressure
made at this point on the artery, from before backwards against
the humerus, will control the blood supply to the arm.
The ulnar artery, the larger of the two vessels into which the
brachial divides, extends along the side of the forearm into
the palm of the hand, where it terminates in the superficial
palmar arch.
The radial artery appears, by its direction, to be a continua-
tion of the brachial, although it does not equal the ulnar in size.
It extends along the front of the forearm as far as the lower
end of the radius, below which it turns round the outer border
of the wrist, descends between the bones of the thumb and fore-
finger, and passes forward into the palm of the hand. It ter-
minates in the deep palmar arch. The superficial and deep
palmar arches supply the hand with blood.
The thoracic aorta extends from the lower border of the fourth
dorsal vertebra, on the left side, to the opening in the diaphragm
below the last dorsal vertebra, and has a length of from S'even
to eight inches. The branches, derived from the thoracic aorta,
are numerous, but small. They are distributed to the walls of
the thorax, and to the viscera contained within it.
The abdominal aorta commences about the lower border of the
last dorsal vertebra, and terminates below by dividing into the
two common iliac arteries. The bifurcation usually takes place
about half-way down the body of the fourth lumbar vertebra,
which corresponds to a spot on the front of the abdomen,
slightly below and to the left of the umbilicus. Its length is
about five inches.
The abdominal aorta gives off numerous branches, which may
be divided into two sets ; viz. those which supply the viscera,
and those which are distributed to the walls of the abdomen.
The former consists of the creliac axis, the superior mesenteric,
PLATE V. — THE ABDOMINAL AORTA AND ITS PRINCIPAL BRANCHES. (Tiede-
mann.) a, ensiform appendix; b, inferior vena cava and c, oesophagus, passing
through diaphragm; /,/, right and left kidneys, with the supra-renal bodies; g, «/,
ureters; h, urinary bladder; k, rectum, divided near its upper end. 1, 1, abdominal
aorta; 2, 2', and 3, 3', right and left inferior phrenic arteries; 4, coeliac axis; 5,
superior mesenteric artery ; 6, 6, renal arteries ; 7, 7, spermatic or ovarian arteries ;
8, inferior mesenteric artery; 10, 10, common iliac arteries; 11, placed between
external and internal iliac arteries.
99
100
ANATOMY FOR NURSES.
[CHAP. IX.
the inferior mesenteric, the supra-renal, the renal, and the sper-
matic or ovarian arteries, while in the latter are included the
phrenic, the lumbar, and the
middle sacral arteries.
The coeliac artery, or axis,
is a short, wide vessel, usually
not iribre than half an inch in
length, which arises from the
front of the aorta, close to the
opening in the diaphragm. It
divides into three branches;
viz. the gastric, which supplies
the stomach ; the hepatic,
which supplies the liver ; and
the splenic, which supplies the
spleen, and in part the stom-
ach and pancreas.
The superior mesenteric ar-
tery arises from the fore part
of the aorta, a little below
the coeliac axis. It supplies
the whole of the small intes-
tine beyond the first portion
(the duodenum) close to the
stomach, and half of the large
intestine.
The inferior mesenteric ar-
tery arises from the front of
the aorta, about an inch and
a half above its bifurcation,
and supplies the lower half
of the large intestine. Con-
tinued under the name of the
superior hemorrhoidal artery,
FIG. 75. — iLiACAXDFEMoRALABTBRiEs.it also supplies the rectum.
The renal arteries are of
large size, in proportion to
the bulk of the organs which they supply. They arise from the
sides of the aorta, about half an inch below the superior mesen-
teric artery, that of the right side being generally a little lower
2, common iliac artery; 4, external iliac;
femoral artery
CHAP. IX.]
THE VASCULAR SYSTEM.
101
down than that of the left. Each is directed outwards, so as to
form nearly a right angle with the aorta. Before reaching the
kidney, each artery divides into four or five branches.
The ovarian arteries, corresponding to the spermatic arteries in
the male, arise close together from the front of the aorta, a little
below the renal arteries. They supply the ovaries, and, joined
to the uterine artery, — a branch
of the internal iliac, — also assist
in supplying the uterus. During
pregnancy the ovarian arteries
become considerably enlarged.
The common iliac arteries, com-
mencing at the bifurcation of the
aorta, pass downwards and out-
wards for about two inches, and
then divide into the internal and
external iliac arteries.
The internal iliac artery (hypo-
gastric) supplies branches to the
walls and viscera of the pelvis.
The external iliac artery forms
a large continuous trunk, which
extends downwards in the lower
limb to just below the knee : it
is named in successive parts of its
course external iliac, femoral, and
popliteal. The external iliac is
placed within the abdomen, and
extends from the bifurcation of the
common iliac to the lower border of
Poupart's ligament, where it enters
the thigh and is named femoral. FIG. 76. — VIEW OF POPLITEAL
rr,, . . , . . , ARTERY. A, biceps muscle; D, D,
Ine femoral artery lies in the gastrocnemius ; /, popliteal artery.
upper three-fourths of the thigh,
its limits being marked above by Poupart's ligament, and below
by the opening in the great adductor muscle, after passing
through which the artery receives the name of popliteal. In
the first part of its course the artery lies along the middle of
the depression on the inner aspect of the thigh, known as
Scarpa's triangle. In this situation the beating of the artery
102
ANATOMY FOR NURSES.
[ClIAP. IX.
may be felt, and the circulation through the vessel may be most
easily controlled by pressure.
The popliteal artery,
continuous with the fem-
oral, is placed at the back
of the knee ; just below
the knee joint it divides
into the anterior and
posterior tibial arteries.
The posterior tibial ar-
tery lies along the back
of the leg, and extends
from the bifurcation of
the popliteal to the
ankle, where it divides
into the internal and
external plantar arteries.
About an inch below
the bifurcation of the
popliteal, the posterior
tibial gives off a large
branch, the peroneal ar-
tery.
The anterior tibial ar-
tery, the smaller of the
two divisions of the
popliteal trunk, extends
along the front of the
leg to the bend of the
ankle, whence it is pro-
longed into the foot
under the name of the
dorsal artery. This
FIG. 77. — DEEP VIEW OF unites with the external
THE ARTERIES OF THE BACK an(J jnternal plantar ar- FIG. 78. -ANTERIOR
OF THE LEG. 1, popliteal ARTERIFS OF THK
artery ; 6, division of pop- tenes to form the plan- 4 anterior tj
liteal into anterior and pos- t h hi h supplies dorsal artery,
tenor tibial arteries ; H, pos-
terior tibial ; 9, peroneal. blood to the f OOt.1
1 Outlining the aorta and its branches as an arterial tree will greatly aid the
student in mastering the arterial distribution. Also colouring the arteries red in the
figures would serve to make their position clearer and more easily remembered.
VIEW
THF: LEG.
artery ; 9,
CHAP. IX.]
THE VASCULAR SYSTEM.
103
Venous return. — The arteries begin as large trunks, which
gradually become smaller and smaller until they end in the
small capillary tubes, while the veins begin as small branches
which at first are scarcely distinguishable from the capillaries.
These small branches, receiving the blood from the capillaries
throughout the body, unite to form
larger vessels, and end at last by
pouring their contents into the
right auricle of the heart through
two large trunks, the superior vena
cava and the inferior vena cava.
The veins, however, which bring
back the blood from the stomach,
intestines, spleen, and pancreas,
do not take the blood directly to
the heart, but first join to form
a large trunk, — the portal vein,
— and carry this blood to the
liver. When the portal vein enters
the liver, it breaks up into cap-
illaries, which, after branching
throughout the liver substance,
unite to form the hepatic veins:
by them the blood is conveyed
into the inferior vena cava. This
constitutes what is called the
portal circulation, and is the only
example in the body of a vein
breaking up into capillaries.
The veins consist of a super-
ficial and a deep set, the former
running immediately beneath the
skin and hence named subcuta-
neous, the latter usually aocom-
panying the arteries and named
venoB comites. These two sets of veins have very frequent com-
munications with each other, and the anastomoses of veins
are always more numerous than those of arteries.
The systemic veins — that is, all the veins of the body with
the exception of the pulmonary and portal veins — are naturally
divided into two groups.
FIG. 79. — ARTERIES OF THE FOOT.
<;, 7, 8,
104
ANATOMY FOE, NURSES.
[CHAP. IX.
I. Those from which the blood is carried to the heart by the
superior vena cava, viz. the veins of the head and neck and
upper limbs, together with those of
the spine and a part of the walls of
the thorax and abdomen. In this
group we may include the veins of
the heart, which, however, pass directly
into the right auricle without entering
the superior vejia cava.
II. Those from which the blood is
carried to the heart by the inferior vena
cava ; viz. the veins of the lower limbs,
the lower part of the trunk, and the
abdominal viscera.
1. The blood returning from the
head and neck flows on each side into
two principal veins, the external and
internal jugular.
The external jugular commences near
the angle of the jaw by the union of
two smaller veins, and descends almost
vertically in the neck to its termination
in the subclavian vein.
The internal jugular, receiving the
blood from the cranial cavity, descends
the neck close to the outer side of the
internal and common carotid arteries.
It unites at a right angle with the
subclavian to form the innominate vein.1
The blood from the upper limbs is
returned by a superficial and deep set
of veins. The superficial are much
larger than the deep, and take a greater
Fio. 80. — SKETCH OF THE
PRINCIPAL VENOUS TRUNKS.
1, superior vena cava; 2, in-
1 NOTE ON VENOUS CIRCULATION OF THE
SKULL. — The blood from the skull is returned
ferior vena cava; 3, right sub- from the smaller veins to the internal jugular
clavian and innominate veins; veins b channelg wh- h are ^ , .
4, left subclavian and mnomi- .
nate veins ; 5, 5, right and left but smuses- These sinuses are spaces left be-
internal jugular veins ; 8, right tween the layers of the dura mater, and are lined
azygos vein ; 10, left azygos by a continuation of the lining membrane of the
vein ; 13, 13, common iliac veins ; veins.
14, 14, sacral veins.
CHAP. IX.]
THE VASCULAR SYSTEM.
105
share in returning the blood, especially from the distal portion
of the limb. The deep veins accompany the arteries, and are
called by the same names. Both
sets are provided with valves, and
terminate in the subclavian vein.
The blood from the spine, walls
of thorax, and abdomen is chiefly
returned by the right and left azygos
veins, which are longitudinal vessels
resting against the thoracic portion
of the spinal column. They com-
municate below with the inferior
vena cava, and terminate above in the
superior vena cava : they thus form a
supplementary channel by which blood
can be conveyed from the lower part
of the body to the heart in case of
obstruction in the inferior vena cava.
The innominate veins, commencing
on each side by the union of the sub-
clavian and internal jugular, behind
the inner end of the clavicle, transmit
the blood returning from the head
and neck, the upper limbs, and a
part of the thoracic wall ; they end
below by uniting to form the superior
vena cava. Both innominate veins
are joined by many side tributaries :
they also receive, at the junction of
the subclavian and internal jugular,
the lymph ; on the left side from the
thoracic duct, and on the right from
the right lymphatic duct.
The superior or descending vena cava
is formed by the union of the right OF LoWEB EXTREMITY.— i, veins
and left innominate veins. It is about of the foot; 2 internal ~&*™£
, vein ; 3, superficial veins of calf ;
three inches long, and opens into the 4> superficial veins of thigh,
right auricle, opposite the third rib.
The blood from the lower limbs is also returned by a super-
ficial and deep set of veins. They are more abundantly supplied
_ S(JPEEFICIAL
106 ANATOMY FOE NURSES. [CHAP. IX.
with valves than the veins of the upper limbs. The deep veins
accompany the arteries. The two largest superficial veins are
the internal or long saphenous, and the external or short saphenous
vein. The internal saphenous extends from the ankle to within
an inch and a half of Poupart's ligament. It lies along the
inner side of the leg and thigh, and terminates in the femoral
vein. The external saphenous arises from the sole of the foot,
and, passing up the back of the leg, ends in the deep popliteal.
Both deep and superficial veins pour their contents into the
external iliac. The blood is returned from the pelvis by the
internal iliac veins, which, uniting with the external iliac, form
the two common iliac veins. Extending from the base of the
sacrum to the fourth lumbar vertebra, the two common iliacs
unite to form the inferior vena cava.
The inferior or ascending vena cava returns the blood from
the lower limbs, pelvis, and abdomen. It begins at the junction
of the two common iliacs, and thence ascends along the right
side of the aorta, perforates the diaphragm, and terminates by
entering the right auricle of the heart. The inferior vena cava
receives many tributaries, the chief of which are the lumbar,
ovarian, renal, and hepatic veins.
The pulmonary artery. — The pulmonary artery conveys the
dark blood from the right side of the heart to the lungs. The
main trunk is a short, wide vessel (diameter 30 mm.) which
arises from the right ventricle and runs for a distance of two
inches backwards and upwards (vide fig. 63). Between the
fifth and sixth dorsal vertebrae, it divides into two branches,
— the right and left pulmonary arteries, — which pass to the
right and left lungs.
The pulmonary veins. — The pulmonary veins are four short
trunks which convey the red blood from the lungs to the left
side of the heart, and which are found — two on each side — in
the root of the corresponding lung. The pulmonary veins have
no valves.
CHAP. IX.]
THE VASCULAR SYSTEM.
107
PLAN OF ARTERIAL DISTRIBUTION.
I.
Arch of Aorta
II.
Thoracic
Aorta
III.
Abdominal
Aorta
R. and L. coronary.
C R. c. carotid.
Innominate j R. subclavian — ax-
l illary — brachial.
L. c. carotid.
L. subclavian.
r Intercostal.
J Pericardial.
I Bronchial.
I (Esophageal.
r Gastric.
Coeliac axis -I Hepatic.
I Splenic.
Sup. mesenteric.
Inf. mesenteric.
Renal.
Ovarian.
Phrenic.
Lumbar.
. Sacral.
( Superficial
Ulnar \ palmar
I arch.
rDeep
Radial paimer
arch,
Common Iliac
arteries.
r _, , ., . , f Ext. plantar i ™
«,..,. , Post, tibial \ T , Plantar
Ext. iliac — fern- \ [ Int. plantar V ^
oral — popliteal I Ant. tibial, dorsal.
I Int. iliac.
arch.
PLAN OF VENOUS RETURN.
The veins from the
head, face, and neck
unite to form
The deep-seated and l R. ,ht & d The internal ju-
superficial veins ^ ^ gular unites
from the upper with the sub-
limbs unite to form J clavians to
form
3 1 External (the external jugular terminates in sub-
clavian veins) and internal jugular veins.
Right 1 _
, , ,. SUP.
and left
. } VE!
mnomi-
CAVA.
nate
The deep-seated and
superficial veins External
from the lower iliacs
limbs unite to form
The veins from pelvis ] Internal
unite to form f iliacs
Right and left 1 INFERIOR VENA
common iliacs J CAVA.
108 ANATOMY FOR NURSES. [CHAP. IX.
The right and left azygos veins connected with the inferior vena cava
below, and superior vena cava above, form a supplementary channel.
The veins from stomach, spleen, pancreas, and intestines unite to form
the portal vein, which breaks up into capillaries in the liver, and is returned
to the inferior vena cava by the hepatic veins.
CHAPTER X.
THE VASCULAR SYSTEM CONTINUED: THE GENERAL CIRCULA-
TION; THE PULSE AND ARTERIAL PRESSURE; VARIATIONS
IN THE CAPILLARY CIRCULATION.
The general circulation of the blood. — At each beat of the
heart the contraction of the ventricles drives a certain quantity
of blood, probably amounting to four
ounces, with great force into the
aorta and pulmonary artery. The
aorta delivers this supply of blood
from the left ventricle, through its
branches, to the capillaries in all
parts of the body, except the lungs.
In the capillaries, the blood is robbed
of oxygen and other constituents
necessary for the life and growth
of the tissues, is loaded with car-
bonic acid and other waste matters,
and is returned by the superior and
inferior venae cavse to the right side
of the heart. From the right side
of the heart, the blood is conveyed
by the pulmonary artery to the
capillaries in the lungs, where it
receives a fresh supply of oxygen
and gives Up the carbonic acid with LATION. A, aorta; P, pulmonary
. i T i • artery; 0, O, auricles; V, V, ven-
which it has become loaded during tricles • / /, intestines ; F, liver ;
its circulation through the body. l£™?^'%?£*™
Thus a double circulation is COn- hepatic veins ; 6, portal vein ; 7, 8,
stantly and simultaneously going
on, the artery from the left side of veins.
109
FIG. 82. — DIAGRAM OF CIRCU-
110 ANATOMY FOR NURSES. [CHAP. X.
the heart sending the pure oxygenated blood to the general
system, and the artery from the right side of the heart sending
the impure blood to the lungs for purification. The more ex-
tensive circulation is usually called the general or systemic
circulation, while the lesser circulation is generally known as
the pulmonary.
Some features of the arterial circulation. — The flow of blood
into the arteries is most distinctly intermittent ; sudden, rapid
discharges alternating with relatively long intervals during
which the arteries receive no blood from the heart. Every
time the heart beats just as much blood flows from the veins
into the right auricle as escapes from the left ventricle into the
aorta, but this inflow is much slower and takes a longer time
than the discharge from the ventricles.
The pulse. — When the finger is placed on an artery a sense
of resistance is felt, and this resistance seems to be increased at
intervals, corresponding to the heart-beat, the artery at each
heart-beat being felt to rise up or expand under the finger.
This constitutes the pulse ; and, in certain arteries which lie
near the surface, this pulse may be seen with the eye. When
the finger is placed on a vein very little resistance is felt ; and,
under ordinary circumstances, no pulse can be perceived by the
touch or by the eye.
As each expansion of an artery is produced by a contraction
of the heart, the pulse, as felt in any superficial artery, is a
convenient guide for ascertaining the character of the heart's
action. The radial artery at the wrist, owing to its accessible
situation, is usually employed for this purpose. Any variation
in the frequency, force, or regularity of the heart's action is
indicated by a corresponding modification of the pulse at
the wrist.
The average frequency of the pulse in man is seventy-two
beats per minute. This rate may be increased by muscular
action. Even the variation of muscular effort entailed between
the standing, sitting, and recumbent positions will make a
difference in the frequency of the pulse of from eight to ten
beats per minute. Age has a marked influence in the same
direction. According to Carpenter, the pulse of the foetus is
about 140, and that of the newly born infant 130. During the
first, second, and third years, it gradually falls to 100 ; by the
CHAP. X.] THE VASCULAR SYSTEM. Ill
fourteenth year to 80 ; and is reduced to the adult standard by
the twenty-first year. At every age, mental excitement may
produce a temporary acceleration, varying in degree with the
^peculiarities of the individual.
As a rule, the rapidity of the heart's action is in inverse ratio
to its force. A slow pulse, within physiological limits, is
usually a strong one, and a rapid pulse comparatively feeble.
The same is true in disturbance of the heart's action in disease ;
the pulse in fever, or other debilitating affections, becoming
weaker as it grows more rapid.
Arterial tension. — When an artery is severed, the flow of
blood from the proximal end (that on the heart side) comes in
jets corresponding to the heart-beats, though the flow does not
cease between the beats. The larger the artery, and the nearer
to the heart, the greater the force with which the blood issues,
and the more marked the intermittence of the flow.
When a corresponding vein is severed, the flow of blood,
which is chiefly from the distal end (that away from the heart),
is not intermittent, but continuous ; the blood comes out with
comparatively little force, and " wells up," rather than " spurts
out."
The continuous, uninterrupted flow of blood in the veins is
caused by the elasticity of the arterial walls. On account of the
small size of the capillaries and small arteries the blood meets with
a great deal of resistance in passing through them; and, in conse-
quence, the blood cannot get through the capillaries into the veins
so rapidly as it is thrown into the arteries by the heart. The
whole arterial system, therefore, becomes over-distended with
blood, and the greater the resistance, the greater the -pressure
on, and distension of, the arterial walls. The following illus-
tration will explain how the elasticity of the arteries enables
them to deliver the blood in a steady flow to the veins through
the capillaries.
If a syringe be fastened to one end of a long piece of elastic
tubing, and water be pumped through the tubing, it will flow
from the far end in jerks. But if we stuff a piece of sponge
into this end of the tubing, or offer in any way resistance to
the outflow of the water, the tubing will distend, its elasticity
be brought into play, and the water flow from the end not in
jerks, but in a stream, which is more and more completely con-
tinuous the longer and more elastic the tubing.
112 ANATOMY FOR NURSES. [CHAP. X.
Substitute for the syringe the heart, for the sponge the cap-
illaries and small arteries, for the tubing the whole arterial sys-
tem, and we have exactly the same result in the living body.
Through the action of the elastic arterial walls the separate jets
from the heart are blended into one continuous stream. The
whole force of each contraction of the heart is not at once
spent in driving a quantity of blood out of the capillaries ; a
part only is thus spent, the rest goes to distend the elastic
arteries. But during the interval between that beat and the
next the distended arteries are narrowing again, by virtue of
their elasticity, and so are pressing the blood on in a steady
stream into the capillaries with as much force as they were
themselves distended by the contraction of the heart.
The degree of tension to which the arterial walls are sub-
jected depends upon the force of the heart-beat, and upon the
resistance offered by the smaller arteries, the normal general
blood pressure being mainly regulated by the " tone " of the
minute arteries.
Variations in the capillary circulation. — Most of the changes
in the capillary circulation are likewise dependent upon the
condition of the smaller arteries. When under certain nervous
influences they contract, the blood supply to the capillaries is
greatly lessened ; when, on the other hand, they dilate, the
blood supply is greatly increased. The phenomena produced
by these local variations in the blood supply of certain parts are
very familiar to us ; the redness of skin produced by an irritat-
ing application, the blushing or paling of the face from mental
emotion, the increased flow of blood to the mucous membranes
during digestion, being all instances of this kind.
But the condition of the capillary walls themselves also
exerts an influence upon the capillary circulation. If some
transparent tissue, preferably the web of a frog's foot, be watched
under the microscope, it will be observed that in the small
capillaries the corpuscles are pressed through the channel in
single file, each corpuscle as it passes occupying the whole bore
of the capillary. In the larger capillaries and smaller arteries
and veins the red corpuscles run in the middle of the channel,
forming a coloured core, between which and the sides of the
vessels is a colourless layer containing no red corpuscles, and
called the "peripheral zone." In the peripheral zone are fre-
CHAP. X.] THE VASCULAR SYSTEM. 113
quently seen white corpuscles, sometimes clinging to the walls
of the vessel, sometimes rolling slowly along, and in general
moving irregularly, stopping awhile, and then suddenly moving
on again.
These are the phenomena of the normal circulation, but a
different state of things sets in when the condition of the blood-
vessels is altered in inflammation.1 If an irritant, such as a
drop of chloroform, be applied to the portion of transparent
tissue under observation, the following changes may be seen to
occur: the arteries dilate, the blood flows in greater quantity
and with more rapidity, the capillaries become filled with cor-
puscles, and the veins appear enlarged and full. This condition
of distension may pass away, and the blood-vessels return to
their normal state, the effect of the irritant having merely pro-
duced a temporary redness.
The irritant, however, usually produces a more decided
change. The white corpuscles begin to gather in the periph-
eral zones, and this takes place though the vessels still
remain dilated and the stream of blood still continues rapid,
though not so rapid as at first. Each white corpuscle exhibits
a tendency to stick to the sides of the vessels, and, driven away
from the arteries by the stronger arterial current, becomes
lodged in the veins. Since white corpuscles are continually
arriving on the scene, the inner surface of the veins and cap-
illaries soon become lined with a layer of these cells. Now,
though the vessels still remain dilated, the stream of blood
begins to slacken, and the white corpuscles lying in contact
with the walls of the vessels are seen to thrust themselves
through the distended walls into the lymph spaces outside.
This migration of the white cells is accomplished by means of
their amoeboid movements. They thrust elongated processes
through the walls, and then, as these processes increase in size,
the body of the cell passes through into the enlarged process
beyond, the perforation appearing to take place in the cement
substance between the pavement epithelial cells forming the
walls of the vessels. Through this migration, the lymph
spaces around the vessels in the inflamed area become crowded
1 The following account of the changes occurring in inflammation does not
strictly belong to a text-book on physiology, but I have ventured to introduce it,
as especially interesting to nurses, out of " Foster's Physiology."
114 ANATOMY FOR NUKSES. [CHAP. X.
with white corpuscles. At the same time the lymph not only
increases in amount, but changes somewhat in its chemical
characters ; it becomes more distinctly and readily coagulable,
and is sometimes spoken of as " exudation fluid." This change
of the lymph with the increased quantity, together with the
dilated crowded condition of the blood-vessels, gives rise to the
swelling which is one of the features of inflammation.
If the inflammation now passes away, the white corpuscles
cease to emigrate, cease to stick so steadily to the sides of the
vessels, the stream of blood quickens again, the vessels regain
their ordinary calibre, and a normal circulation is re-established.
But this inflammatory condition, instead of passing off, may go
on to a further stage ; and, if this is the case, more and more
white corpuscles, arrested in their passage, crowd and block the
channels, so that, though the vessels remain dilated, the stream
becomes slower and slower, until at last it stops altogether, and
stagnation or " stasis " sets in. The red corpuscles, in this con-
dition of things, are driven in among the white corpuscles, the
vessels are filled and distended with a mingled mass of red and
white corpuscles, and it may now be observed that the red cor-
puscles also begin to find their way through the distended and
altered walls of the capillaries into the lymph spaces outside.
This is called the diapedesis of the red corpuscles.
This stagnation stage of inflammation may be the beginning
of further mischief and of death to the inflamed tissue, but it,
too, may, like the earlier stages, pass away.
General summary of the circulation. — The perfect circulation
of the blood is dependent upon certain factors, the chief of
which are : (1) the character of the heart-beat ; (2) the con-
traction and relaxation of the minute arteries ; (3) the elas-
ticity and extensibility of the arterial walls ; (4) the perfect
adjustment of the valves.
The character of the heart-beat is mainly determined by the
condition of its muscular substance, and any interference with
the nutrition of the heart leading to degeneration of its mus-
cular walls very seriously affects the heart's action.
The contraction and relaxation of the smaller arteries is
under the influence of the nervous system, the particular fibres
distributed to them being known as the vaso-motor nerves.
The widening and narrowing of these arteries not only affects
CHAP. X.] THE VASCULAR SYSTEM. 115
the local circulation in different parts of the body, but the
amount of resistance they oppose to the arterial impulse also
influences in some degree the character of the heart-beat.
The elasticity and extensibility of the arteries change with
the age of the individual. As we grow older the arterial walls
grow stiffer and more rigid, a'nd become less well adapted for
the unceasing work they are called upon to perform. The
valves also show signs of age as years advance, and even if not
injured by disease, do not adjust themselves so perfectly as in
early life.
Still, the heart has a marvellous facility for adjusting itself
to changed conditions, and the circulation of the blood may
go on for years with the integrity of the vascular mechanism
greatly impaired.
FOETAL CIRCULATION. — The peculiarities of the foetal circu-
lation, leaving details aside, are — the direct communication
between the two auricles of the heart through an opening
called the foramen ovale ; the communication between the pul-
monary artery and descending portion of the arch of the aorta
by means of a tube called the ductus arteriosus ; and the com-
munication between the placenta and the foetus by means of
the umbilical cord.
The arterial blood for the nutrition of the foetus is carried from
the placenta along the umbilical cord by the umbilical vein.
Entering the foetus at the umbilicus the blood passes upwards
to the liver and is conveyed into the inferior vena cava in two
different ways. The larger quantity first enters the liver, and
alone, or in conjunction with the blood from the portal vein,
ramifies through the liver before entering the inferior vena
cava, by means of the hepatic veins. The smaller quantity of
blood passes directly from the umbilical vein into the inferior
vena cava, by a tube called the ductus venosus.
In the inferior vena cava the blood from the placenta
becomes mixed with the blood returning from the lower ex-
tremities of the foetus. It enters the right auricle and guided
by a valve, the Eustachian valve, passes through the foramen
ovale into the left auricle. In the left auricle it unites with a
small quantity of blood returned from the lungs by the pul-
monary veins. From the left auricle the blood passes into the
left ventricle, and is distributed by the aorta almost entirely to
PLATE VI. — PLAN OF F(ETAL CIRCULATION. In this plan, the figured arrows rep-
resent the kind of blood, as well as the direction which it takes in the vessels. Thus,
arterial blood is figured ; venous blood — — ; mixed (arterial and venous)
116
CHAP. X.] THE VASCULAR SYSTEM. 117
the upper extremities. Returned from the upper extremities
by the superior vena cava the blood enters the right auricle
and, passing over the Eustachian valve, descends into the right
ventricle, and from the right ventricle into the pulmonary
artery. As the lungs in the foetus are solid, they require very
little blood, and the greater part of the blood passes through
the ductus arteriosus into the descending aorta, where, mixing
with the blood delivered to the aorta by the left ventricle, it
descends to supply the lower extremities of the foetus, the chief
portion of this blood, however, being carried back to the pla-
centa by the two umbilical arteries.
From this description of the foetal circulation, it will be
seen : —
1. That the placenta serves the double purpose of a respi-
ratory and nutritive organ, receiving the venous blood from
the foetus, and returning it again charged with oxygen and
additional nutritive material.
2. That the greater part of the blood traverses the liver
before entering the inferior vena cava ; hence the large size of
this organ at birth.
3. That the blood from the placenta passes almost directly
into the arch of the aorta, and is distributed by its branches to
the head and upper extremities ; hence the large size and
perfect development of those parts at birth.
4. That the blood in the descending aorta is chiefly derived
from that which has already circulated in the upper extremities,
and, mixed with only a small quantity from the left ventricle,
is distributed to the lower extremities ; hence the small size and
imperfect development of these parts at birth.
Development of blood-vessels and corpuscles. — The blood-vessels and
red corpuscles are formed very early in the embryo. They are developed in
that portion of the primitive tissue called the mesoblast. The cells which
are to form the vessels become extended into processes of varying length,
which grow out from the cells in two or more directions. The cells become
united with one another, either directly or by the junction of their processes,
so that an irregular network is thus formed. Meanwhile the nuclei in the
cells multiply, and each nucleus surrounds itself with a small amount of
cell protoplasm . The corpuscles thus formed acquire a reddish colour, and
the protoplasmic network in which they lie becomes hollowed out into a
system of branched canals containing fluid, in which the nucleated coloured
corpuscles float. The protoplasmic walls of the vessels gradually change
118
ANATOMY FOE NUESES.
[CHAP. X.
into the flattened cells which compose the wall of the capillaries, and which
form the lining membrane of the arteries and veins. The remaining coats
P
FIG. 83. — ISOLATED CAPILLARY NETWORK FORMED BY THE JUNCTION OP
SEVERAL HOLLOWED-OUT CELLS, AND CONTAINING COLOURED BLOOD-CORPUSCLES
IN A CLEAR FLUID, p, p, pointed cell-processes extending in different directions
for union with neighbouring capillaries.
of the larger vessels are developed later from other cells which apply them-
selves to the exterior of these tubes.
The first white corpuscles do not appear in the vessels so early as the
coloured ones. They probably occur in the beginning as free cells and
wander in from the outside.
The new vessels which form in the healing of wounds and in the restora-
tion of lost parts are produced by a process which is essentially the same as
above described. Blood-corpuscles, however, are not produced within them,
and it is still a matter of doubt as to where and how the red corpuscles
originate after birth. The white corpuscles are undoubtedly produced to a
large extent in the lymphatic glands and other lyrnphoid structures.
CHAPTER XI.
VASCULAR SYSTEM CONCLUDED: LYMPHATIC VESSELS AND
LYMPH. LYMPHATIC GLANDS AND BODIES OF ALLIED
STRUCTURE.
The lymphatics. — In addition to the blood-vessels, which form
a continuous series of tubes for the passage of the blood, there
is another system of vessels in the body, which arise in the
different tissues, and pour their contents into the great veins
near the heart. The fluid which these vessels contain is ab-
sorbed from the tissues, and is called, from its transparent
watery appearance, " lymph " (lympha, water), while the ves-
sels themselves are known as lymphatics or absorbents.
The absorbents may be divided into two sets: the lacteals,
which absorb the milk-like fluid, called chyle, from the intes-
tines and carry it to the thoracic duct; arfd the lymphatics
proper, which take up the lymph from all parts of the body and
return it to the blood through the thoracic and right lym-
phatic ducts. These two sets of vessels, however, are alike in
structure, and will be considered together under the general
name of lymphatics.
The lymphatics are found in nearly all the tissues that are
supplied with blood. The larger trunks usually accompany the
deep-seated blood-vessels, and the smaller vessels form networks
in all parts of the body where the extensively distributed and
penetrative connective tissue is found.
The lymphatics have their origin in the connective tissue.
They may be said to begin as irregularly shaped or tubular
spaces in the areolse, and are distinguished from the lymph
spaces in the tissue outside by being lined with a single layer of
flat, transparent epitheloid cells having a peculiar dentated out-
line, by means of which they are readily recognized. These
119
120 ANATOMY FOR NURSES. [CHAP. XI.
united lymph vessels form very irregular labyrinths, communi-
cate freely with one another, and are altogether wider than the
blood capillaries. They form the link between the lymph in
FIG. 84. — A SMALL PORTION OF A LYMPHATIC PLEXUS. Magnified 110 diam-
eters. (Ranvier.) L, lymphatic vessel with characteristic epithelium; C, cell
spaces of the connective tissue abutting here and there against the lymphatics.
the tissues outside of themselves and the regular lymphatic
vessels into which they open.1
In structure, the larger lymphatic vessels closely resemble
the veins, except that their walls are somewhat thinner and
more transparent, and are more abundantly supplied with
valves. The valves are constructed and arranged in the same
fashion as those of the veins, but follow one another at such
short intervals, that, when distended, they give the vessel a
beaded or jointed appearance. They are usually wanting in
the smaller networks. The valves allow the passage of mate-
rial from the smaller lymphatics to the veins, and obstruct
the flow of anything in the Apposite direction. The lymphatics
do not carry to the tissues. /Their office is to carry away from
the tissues into the veins all the material the tissues do not need.
1 The serous cavities may be regarded as expanded lymph spaces, as they
open by means of their stpmata into the lymphatics, and the fluid which
moistens their surfaces is really lymph and not serum.
CHAP. XI.] THE VASCULAB SYSTEM. 121
The lymphatics, having attained a certain size, do not unite
into larger and larger trunks, but continue of the same diameter
until they finally enter two trunks or ducts through which
their contents are poured into the veins. The lymphatics from
the right arm, and right side of the head, neck, and upper part
of the trunk, enter the right lymphatic duct. The vessels from
the rest of the body, including the lacteals from the intestines,
enter the thoracic duct. As we have stated elsewhere (page
105), these ducts pour their contents into the blood at the
junction of the internal jugular and subclavian veins.
The lymph, like the blood in the veins, is returned from the
limbs and viscera by a deep and by a superficial set of vessels.
In their course from origin to termination most of the lym-
phatics pass through small masses of tissue, called lymphatic
glands, a description of which will be given later on.
The thoracic duct. — The thoracic duct, from fifteen to eigh-
teen inches long in the adult, extends from the second lum-
bar vertebra to the root of the neck. It lies in front of the
bodies of the vertebrae gradually inclining towards the left
until, when on a level with the seventh cervical vertebra, it
turns outward and arches downwards and forwards to terminate
in the angle formed by the junction of the left internal jugular
and subclavian veins. The size is usually compared to that of
a goose quill. It is dilated below where it receives the lym-
phatics from the lower limbs and the chyle , from the lacteals,
the dilatation being known as the receptaculum chyli, recep-
tacle of the chyle. The duct is provided with valves, and in
other respects closely resembles the larger lymphatics in struc-
ture. It is often alternately contracted and enlarged at irregular
intervals.
The right lymphatic duct is a short vessel usually from a quar-
ter to half an inch in length. It pours its contents into the
blood at the junction of the right internal jugular and sub-
clavian veins.
The lymph. — The lymph is blood minus certain constituents.
When examined with the microscope, it is seen to consist of a
clear liquid with corpuscles floating in it. The liquid part
resembles the plasma of the blood in its composition, except
that it contains relatively more water and less solids. It clots
when removed from the body, though not so firmly as the
122 ANATOMY FOR NURSES. [CHAP. XI.
blood. The lymph corpuscles, usually called leucocytes, agree
in their characters with the white corpuscles of the blood.
They vary in number in different parts, being more numerous
in the lymph which has passed through the lymphatic glands
than in that which enters these bodies, thus indicating the lym-
phatic glands as a source of these corpuscles.
The chyle in the lacteals during digestion has a white aspect
dependent upon the fatty particles absorbed from the food, and
suspended in it like oil globules in milk. After fasting the
lacteals contain lymph which differs very little from the lymph
found in the ordinary lymphatics.
The lymph, broadly speaking, is blood minus its red corpuscles.
The chyle is lymph plus a very large quantity of minutely
divided fat.
Movements of the lymph. — The onward progress of the lymph
from the tissues to the veins is maintained chiefly by three
things. (1) The difference of the pressure upon the lymph in
the tissues, and the pressure in the large veins of the neck. As
we have already seen in our last chapter the pressure exerted
upon the blood in the capillaries is greater than that exerted
upon the blood in the veins. This pressure in the smaller blood-
vessels is communicated through the blood-plasma to the lymph,
and thus, though the lymph is not subjected to the same amount
of pressure as the blood in the capillaries, it still stands at a
higher pressure than the blood in the veins. We may consider
the lymphatics to form a system of vessels leading from a region
of higher pressure, viz. the lymph-spaces of the tissues, to a
region of lower pressure, viz. the interior of the large veins of
the neck. (2) On account of the numerous valves in the
lymphatics every pressure upon the tissues in which they lie
will, by compressing the vessels, cause an outward flow of their
contents. Active muscular exercise and the manipulation of
the tissues, as practised in massage, markedly affect the lymph
flow. (3) During each inspiration the pressure on the thoracic
duct is less than on the lymphatics outside the thorax, and the
lymph is accordingly "sucked" into the duct. During the
succeeding expiration the pressure on the thoracic duct is in-
creased, and some of its contents, prevented by the valve from
escaping below, are pressed out into the veins.
The lymph in the various lymph-spaces of the body varies in
CHAP. XL] THE VASCULAR SYSTEM. 123
amount from time to time, but under normal circumstances,
never exceeds certain limits. Under abnormal conditions, these
limits may be exceeded, and the result is known as oadema or
dropsy. Similar excessive accumulations may also occur in the
larger lymph-spaces, the serous cavities.
The possible causes of oedema are, on the one hand, an ob-
struction to the flow of lymph from the lymph-spaces, and on
the other hand, an excessive trans udation, the lymph gathering
in the lymph-spaces faster than it can be carried away by a
normal flow. QEdema is almost always due to the latter cause,
viz. excessive transudation.
The inflammatory oedema, due to changes in the walls of the
blood-vessels, we have already touched on in speaking of the
capillary circulation. In this kind of oedema the transudation
is, besides being crowded with migrating corpuscles, more dis-
tinctly coagulable than ordinary lymph. Allied to this inflam-
matory oedema is the "effusion," which appears in the serous
cavities when they are inflamed, as in pleurisy and peritonitis.
Functions of the lymph. — • The lymph derived from the blood
delivers to the elements of the tissues the material each element
needs to maintain its functional activity, and returns to the
blood the products of this activity, which products may be
simple waste, or matters capable of being made use of by some
other tissue. There is thus a continual interchange going on
between the blood and the lymph. How this interchange
is effected may be partially understood by the following
illustration.
If a tumbler be completely divided vertically into two com-
partments by a moist piece of memlprane, and a watery solution
of common salt be placed in one compartment, and a watery
solution of sugar in the other, it will be found after a time that
some of the salt has found its way into the solution of sugar,
and, vice versa, some of the sugar into the salt solution. Such
an interchange is said to be due to dialysis or osmosis ; and if
the process were allowed to go on for some hours, the same
proportion of salt and sugar would be found in the solutions on
each side of the dividing membrane. So in the living body.
The lymph, originally like the blood-plasma (it is blood-plasma
forced to transude through the capillaries by the pressure of the
blood), becomes altered by the metabolic changes of the tissues
124
ANATOMY FOR NURSES.
[CHAP. XL
which it bathes, and we have two different fluids, separated by
the moist membrane which forms the walls of the blood-vessels,
— the lymph in the tissues outside the walls of the capillaries
and the blood inside the capillary walls, — and the same condi-
tions may be said to exist as in the salt and sugar solutions just
spoken of. And now the same phenomena take place ; for
though the pressure is higher in the blood-vessels than in the
lymph outside, some of the constitu-
ents of the lymph pass into the blood
by the process of osmosis.
These constituents, which, as we
cannot too often emphasize, are prod-
ucts resulting from the activity of
the tissues, are carried away by the
blood to other tissues, which will
either make use of them, or, as in
the kidneys, take them up to make
excretory fluids, and so remove them
from the body.
In consequence of the different
wants and wastes of different tissues
at different times, both the lymph
and blood must vary in composition
in different parts of the body. But
the loss and gain is so fairly balanced
that the average composition is pretty
constantly maintained. The blood, on
account of the higher pressure, loses
more liquid to the lymph than it re-
ceives back, but this excess is returned
back again to the blood by the lym-
phatics when they empty their con-
tents into the veins.
Lymphatic glands. — The lymphatic
glands are small, solid bodies, placed
in the course of the lymphatics and
lacteals, through which the contents
of most of these vessels have to pass in their progress towards
the thoracic and right lymphatic ducts. These bodies are col-
lected in numbers alongside of the great muscles of the neck,
FIG. 85. — LYMPHATICS AND
LYMPHATIC GLANDS OF AXILLA
AND ARM.
CHAP. XI.]
THE VASCULAR SYSTEM.
125
and also in the thorax and abdomen, especially in the mesentery,
where they are called the mesenteric glands, and alongside
of the aorta, vena cava inferior, and the iliac vessels. A few,
usually of small size, are found on the external parts of the
head, and considerable groups are situated in the axilla, and
in the groin, where they receive the name of inguinal glands.
Some three or four lie on the popliteal vessels, and usually one
is placed a little below the knee, but none farther down. In
the arm, they are found as low as the elbow joint.
The size of the lymphatic glands is very various, some being
not much larger than a hemp seed, and others as large as an
almond, or even larger than this. In shape, they are usually
oval.
A lymphatic gland is covered by an envelope, or capsule, of
connective and muscular tissue. This capsule sends fibrous
FIG. 86. — DIAGRAMMATIC SECTION OF LYMPHATIC GLAND. (Sharpey.) a./,
afferent lymphatic; e.l, efferent lymphatic; c, capsule, or envelope; tr, trabeculae;
l.s, lymph-sinus ; l.h, pulpy substance of gland.
bands (trabeculce) into the substance of the gland, dividing the
exterior portion into more or less regular compartments, and
the interior into irregular labyrinths. This framework is occu-
126
ANATOMY FOR NURSES.
[CHAP. XT.
pied by reticular or lymphoid tissue,1 the fine meshes of which
are filled with leucocytes. Between this pulpy substance of the
gland and the skeleton framework there is a narrow space (left
white in the diagram) which looks as if the pulp had originally
filled the framework and then shrunk away slightly on all sides.
The spaces thus left form channels for the passage of the lymph,
which, entering the more convex surface by afferent vessels,
issues, after circulating through the gland, by efferent vessels
below. In its passage through the gland the lymph takes up
fresh leucocytes, which are continually multiplying by cell
division in the glandular substance. The lymphatic glands are
plentifully supplied with blood.
Solitary follicles and Peyer's patches. — Closely connected with
the lymphatic vessels in the intestines are small, rounded bodies
FIG. 87. — VERTICAL SECTION OF A PORTION OF A PEYER'S PATCH, WITH LAC-
TEAL VESSELS INJECTED, a, villi, with their lacteals coloured black ; d, surface of
rounded follicle, or solitary gland; e, central part; /, g, h, i, and k, lymph-channels,
or lacteal vessels, coloured black.
of the size of a small pin's head, called solitary glands or follicles.
These bodies consist of a rounded mass of fine lymphoid tissue,
the meshes of which are crowded with leucocytes. Into this
mass of tissue one or more small arteries, enter and form a
1 Reticular or lymphoid tissue is that variety of connective tissue in which
the branched connective tissue cells unite to form delicate networks. The
meshes of the network are occupied by fluid in which the leucocytes often, in
large numbers, wander to and fro.
CHAP. XI.] THE VASCULAR SYSTEM. 127
capillary network, from which the blood is carried away by one
or more small veins. Surrounding the mass are lymph channels
which are continuous with the lymphatic vessels in the tissue
below.
A Peyer's patch, or " agminated gland," as it is often called, is
simply a collection of these follicles. A well-formed Peyer's
patch consists of fifty or more of these solitary follicles, ar-
ranged in a single layer, close under the epithelium of the
intestinal mucous membrane, and stretching well down into
the tissue beneath. These patches are circular or oval in shape,
and from twenty to thirty in number. They are largest and
most numerous in the portion of the intestine called the ilium.
They increase in size during digestion.
The tonsils are two thick masses of lymphoid tissue, placed
one on each side of the fauces or throat, into which they pro-
ject. They are covered by stratified epithelium, and their sur-
faces are pitted with apertures which lead into recesses or crypts
in the substance of the tissue.
The spleen. — The spleen differs in many important particu-
lars from lymphatic glands, but may be conveniently studied in
conjunction with them, as it resembles these glands in structure,
and is functionally connected with the blood.
Like the lymphatic glands, the spleen is covered by a fibrous
and muscular capsule which sends fibrous bands to form a net-
work in the interior of the organ. In the meshes of the fibrous
framework lies a soft pulpy substance containing a large
amount of blood, and, therefore, of a deep red colour. This
soft, red pulp is dotted with whitish specks, which are small
masses of lymphoid tissue, and are called the Malpighian cor-
puscles of the spleen.
The blood supplied to the spleen appears to escape from the
minute subdivisions of the arteries into the red pulp before
entering the exceedingly thin-walled veins by which it is con-
veyed from the gland. The pulp contains numerous red cor-
puscles, and many bodies which appear to be red corpuscles in
process of decay or destruction, and it is surmised that the red
corpuscles are in some way destroyed, and that additional white
corpuscles are formed, within the spleen.
The spleen is covered by a portion of the peritoneum, the
serous membrane covering the viscera of the abdomen, and
128 ANATOMY FOB NURSES. [CHAP. XI.
lies upon the left side of the stomach, in the abdominal cavity.
It is an elongated, flat body, varying greatly in size at different
periods of life. The size is increased during and after diges-
tion, and is always large in well-fed, and small in starved,
animals. In certain diseases, and more especially in ague, a
temporary enlargement takes place. In prolonged ague, a per-
manent enlargement of the spleen occurs, and forms the so-
called "ague cake."
CHAPTER XII.
THE RESPIRATORY APPARATUS: LARYNX; TRACHEA; LUNGS.
RESPIRATION; EFFECTS OF RESPIRATION UPON THE AIR
WITHIN THE LUNGS, UPON THE AIR OUTSIDE THE BODY,
UPON THE BLOOD; MODIFIED RESPIRATORY MOVEMENTS.
The respiratory apparatus. — Respiration is the main process
by means of which the body is supplied with oxygen and re-
lieved of carbonic acid.
A respiratory apparatus consists essentially of a moist and
permeable membrane, with blood-vessels containing carbonic
acid on one side, and air or fluid containing oxygen on the
other. In most aquatic animals, the respiratory organs have
the form of gills; in terrestrial or air-breathing animals, the
respiratory organs are situated internally under the form of
lungs, and are placed in communication with the external air
by a tube or windpipe.
In man, the respiratory apparatus may be conveniently di-
vided into the larynx, trachea, and lungs.
The larynx. — The larynx is situated between the base of the
tongue and the top of the trachea, in the upper and front part
of the neck. Above and behind lies the pharynx, which opens
into the oesophagus or gullet, and on either side of it lie the great
vessels of the neck.
The larynx is made up of nine pieces of cartilage, united
together by ligaments, and moved by numerous muscles. It is
lined throughout by mucous membrane,1 which is continuous
above with that lining the pharynx, and below with that lining
the trachea. In form, the larynx is narrow and rounded below
1 Mucous membranes resemble the skin in structure, and may be said to
form an internal skin for the cavities of the body which open exteriorly. They
always have a basis of connective tissue, are lined with epithelium, and secrete
a sticky substance called mucus. For a further description, see page 144.
it 129
130
ANATOMY FOR NUKSES. [CHAP. XII.
where it blends with the trachea, but broad above, and shaped
somewhat like a triangular box, with flat sides and prominent
ridge in front. This prominence, popularly called "Adam's
apple," is formed by the union of the two largest pieces of
cartilage (the thyroid), of which the larynx is composed.
Across the middle of the larynx is a transverse partition,
formed by two folds of the lining-
mucous membrane, stretching from
side to side, but not quite meeting
in the middle line. They thus
leave in the middle line a chink or
slit, running from front to back,
called the glottis or rima glottidis.
Imbedded in the mucous mem-
branes at the edges of the slit are
fibrous and elastic ligaments, which
strengthen the edges of the glottis
and give them elasticity. These
ligamentous bands, covered with
the mucous membrane, are firmly
attached at either end to the car-
tilages of the larynx, and are
called the vocal cords. The space
left between their edges, the glottis*
varies in shape and size, according
to the action of the muscles upon
PHARYNX, WITH THE "COMMEND the laryngeal walls. When the
MENT OF GULLET AND LARYNX, AS larynx is at rest during quiet
EXPOSED BY A SECTION A LITTLE TO , J , . , . . .
THE LEFT OF THE MED^N PLANE OF breathing, the glottis is V-shaped;
THE HEAD, a, vertebrae ; 6, gullet ; during a deep inspiration, it be-
c, trachea; d, larynx; e, epiglottis; , , ., ,
/, soft palate; g, opening of Eus- comes almost round; while, during
tachian tube; k, tongue; i, hard the production of a high note, the
palate; o, p, q, inferior turbinate
bones of left nasal chamber. edges of the cords approximate so
closely as to leave scarcely any
opening at all. The glottis is protected by a leaf-shaped lid of
fibro-cartilage, called the epiglottis, which shuts down upon the
opening during the passage of food or other matters into the
oesophagus.
The vocal cords produce the voice. A blast of air, driven by
an expiratory movement out of the lungs, throws the two
FIG. 88. — THE MOUTH, NOSE, AND
CHAP. XII.]
KESPIKATIOK
131
elastic cords into vibrations. These impart their vibrations to
the column of air above them, and so give rise to the sound
which we call the voice.
The larynx is placed in communication with the external air
by two channels: the one, supplied by the nasal passages, is
always open ; the other, furnished by the mouth, can be opened
and closed at will.
One advantage of this
arrangement is, 'that
when exposed to a
very cold temperature,
we can close our
mouths and breathe
through the nasal pas-
sages, which, being nar-
row, thickly lined, and
freely supplied with
blood - vessels, warm
the air before it reaches
the lungs.
The trachea. — The
trachea or windpipe is
a fibrous and muscu-
lar tube, the walls of
which are strengthened
and rendered more
rigid by hoops of car- FIG. 89. — THE LARYNX AS SEEN BY MEANS OF
tilage embedded in the THE LARYNGOSCOPE IN DIFFERENT CONDITIONS
{ OF THE GLOTTIS. A, while singing a high note ; B,
fibrous tissue. These
hoom
in quiet breathing; (7, during a deep inspiration.
'» base of tonSue; e> uPPer free edSe of epiglottis ;
e', cushion of the epiglottis ; ph, part of anterior
and incomplete behind, wall of pharynx; cv, the true vocal cords; cvs, the
tllP Pflr til a crin mi- rinrr* false VOCal CO1'ds ' tr> the trachea with its ***&'> 6'
tne cartilaginous rings the two bronchi at their corainencement.
being completed by
bands of plain muscular tissue where the trachea comes in con-
tact with the oasophagus. Like the larynx it is lined by mucous
membrane, and has a ciliated epithelium upon its inner surface.
The mucous membrane, which also extends into the bronchial
tubes, keeps the internal surface of the air passages free from
impurities; the sticky mucus entangles particles of dust and
other matters breathed in with the air, and the incessant
132 ANATOMY FOE, NUESES. [CHAP. XII.
movements of the cilia continually sweep this dirt-ladened
mucus upwards and outwards.
The trachea measures about four and a half inches in length,
FIG. 90. — FRONT VIEW OF CARTILAGES OF LARYNX. Trachea and bronchi.
and three-quarters of an inch from side to side. It extends
down into the thorax from the lower part of the larynx to
opposite the third dorsal vertebra, where it divides into two
tubes, — the two bronchi, — one for each lung.
CHAP. XII.]
RESPIKATION.
133
The lungs. — The lungs consist of the bronchial tubes and
their terminal dilatations, numerous blood-vessels, lymphatics,
and nerves, and an abundance of fine, elastic, connective tissue,
binding all together.
The two bronchi, into which the trachea divides, enter the
right and left lung respectively, and then break up into a great
number of smaller branches which are called the bronchial
tubes. The two bronchi resemble the trachea in structure ; but
as the bronchial tubes divide and subdivide, their walls become
thinner, the small plates of cartilage drop off, the fibrous tissue
disappears, and the finer tubes are composed of only a thin
layer of muscular and elastic tissue, lined by mucous membrane.
Finally, these finer tubes end in
dilated cavities, the walls of which,
consisting of a single layer of flat-
tened epitheloid cells, surrounded
by a fine, elastic, connective tissue,
are exceedingly thin and delicate.
Immediately beneath the layer of
flat cells, and lodged in the elastic
connective tissue, is a very close
network of capillary blood-vessels;
and the air reaching the terminal
dilatations by the bronchial tubes is
separated from the blood in the
capillaries by only the thin mem-
branes forming their respective
walls.
The terminal dilatations do not end as simple, rounded sacs,
like children's air-balloons, but each bronchiole ends in an
enlargement having more or less the shape of a funnel, and
called an infundibulum. Each of these infundibula is sub-
divided into secondary chambers or cavities, called alveoli, the
walls of which are honey-combed with " bulgings." * In this
way the amount of surface exposed to the air and covered by
the capillaries is immensely increased.2
1 These protrusions may be illustrated by a pea-pod, the walls of which are
filled with " bulgings," made by the pressure of the peas.
2 The pulmonary alveoli are often spoken of under the general name of air-
sacs, and the "bulgings " are known as air-cells.
FIG. 91. — Two ALVEOLI OF THE
LUNG. Highly magnified. 6, &,
the air-cells, or bulgings, of the
alveoli, a, a.
134 ANATOMY FOR, NURSES [CHAP. XII.
Broadly speaking, the lungs may be said to consist of a large
amount of a film-like elastic membrane, covered by a close net-
work of blood-vessels, which membrane is arranged in the form
of irregularly dilated pouches at the end of fine tubes, opening
into larger and larger tubes, and finally into the windpipe,
which places them in communication with the external air.
By virtue of their structure, the larger bronchial tubes
remain permanently open ; the smaller tubes, however, are sub-
FIG. 92. — ANTERIOR VIEW OF LUNGS AND HEART. 1, heart; 2, inferior vena
cava ; 3, superior vena cava ; 4, right innominate vein ; 5, left innominate vein ;
6, jugular vein; 7, subclavian vein; 8, arch of aorta; 8', subclavian artery; 9, left
pulmonary artery; 9', 9', carotid artery; 10, trachea; 11, left bronchus; 12, rami-
fications of right bronchus exposed in upper lobe of right lung ; 13, 14, middle lobe ;
15, lower lobe; It), upper lobe of left lung; 17, lower lobe of left lung.
ject to collapse when empty; they also may contract under
certain nervous influences. The terminal dilatations are emi-
nently elastic and continually expand and contract; they are
bathed with lymph, and are always moist.
The two lungs occupy almost all the cavity of the thorax
which is not taken up by the heart. The right lung is the
larger and heavier; it is broader than the left, owing to the
inclination of the heart to the left side ; it is also shorter by one
CHAP. XII.] RESPIRATION. 135
inch, in consequence of the diaphragm rising higher on the right
side to accommodate the liver. The right lung is divided by
fissures into three lobes. The left lung is smaller, narrower,
and longer than the right, and has only two lobes. Each lung
is enclosed in a serous sac, the pleura, one layer of which is
closely adherent to the walls of the chest and diaphragm ; the
other closely covers the lung. The base of each lung is at-
tached, by means of the pleura, to the diaphragm, and the apex
is attached above the margin of the first rib. The two layers
of the pleural sacs, moistened by lymph, are normally in close
contact ; they move easily upon one another, and prevent the
friction that would otherwise occur between the lungs and the
walls of the chest with every respiration.
The pressure of the atmospheric air upon the lungs through
the air-passages is greater than it can possibly be upon them
from the outside through the chest walls, on account of the
resistance which the solid chest walls offer to this pressure ;
and, ordinarily, it is impossible for the lungs to pull away
the layer of the pleural sac which adheres to them from the
layer which is attached to the chest wall. If, however, the
chest wall be punctured, the air from the outside will rush in,
distend the pleura, and, squeezing the air out of the air-sacs into
the air-passages, cause the lungs to shrivel up and collapse.
Respiration. — The lungs, then, are placed in an air-tight tho-
rax, which they, together with the heart and great blood-vessels,
completely fill. By the contraction of certain muscles (see page
65), the cavity of the thorax is enlarged; the lungs are cor-
respondingly distended to fill the enlarged cavity, and, by this
distension, the air within the air-sacs becomes expanded and
more rarefied than the air outside. Being thus expanded and
rarefied, the pressure of the air within the lungs becomes less
than that of the air outside, and this difference of pressure
causes the air to rush through the trachea into the lungs, until
an equilibrium of pressure is established between the air inside
the lungs and that outside. This constitutes an inspiration.
Upon the relaxation of the inspiratory muscles, the elasticity
of the lungs and the chest walls causes the chest to return to
its original size, in consequence of which the air within the
lungs becomes more contracted and denser than the air outside,
the pressure within becomes greater than the pressure without,
136 ANATOMY FOR NURSES. [CHAP. XII.
and the air rushes out of the trachea until equilibrium be once
more established. This constitutes an expiration. An inspira-
tion and an expiration make a respiration.
As in the heart, the auricular systole, the ventricular systole,
and then a pause, follow in regular order, — so in the lungs,
the inspiration, the expiration, and then a pause succeed one
another. Each respiratory act in the adult is ordinarily repeated
from fifteen to eighteen times per minute. But this rate varies
under different circumstances, one of the most important of
which is age. The average rate in the newly born infant has
been found to be forty-four per minute, and at the age of five
years, twenty-six per minute. It is reduced between the ages
of fifteen and twenty to the normal standard.
A condition of rest or activity readily influences the number
of respirations per minute. They are always less frequent
during sleep, and are markedly increased by severe muscular
exercise.
Respiration is an involuntary act. It is possible for a short
time to increase or retard the rate of respiration within certain
limits by voluntary effort, but this cannot be done continuously.
If we intentionally arrest the breathing or diminish its fre-
quency after a short time the nervous impulse becomes too
strong to be controlled, and the movements will recommence
as usual. If, on the other hand, we purposely accelerate res-
piration to any great degree, the exertion soon becomes too
fatiguing for continuance, and the movements return to their
normal standard.
The nervous impulses which cause the contractions of the
respiratory muscles arise in the medulla oblongata, travel down
the spinal cord, and out along the phrenic and intercostal
nerves. If the portion of the medulla oblongata, where these
nervous impulses arise, be removed or injured, respiration
ceases, and death at once ensues. This part of the medulla is
known as the respiratory centre, and is also often called the
"vital knot."
The effects of respiration upon the air within the lungs. — At
birth the lungs contain no air. The walls of the air-sacs are in
close contact, and the walls of the smaller bronchial tubes or
bronchioles collapsed and touching one another. The trachea
and larger bronchial tubes are open, but contain fluid and not
CHAP. XIL] RESPIRATION. 137
air. When the chest expands with the first breath taken, the
inspired air has to overcome the adhesions existing between
the walls of the bronchioles and air-sacs. The force of this
first inspiratory effort, spent in opening out and unfolding, as it
were, the inner recesses of the lungs, is considerable. In the
succeeding expiration, most of the air introduced by the first
inspiration remains in the lungs, succeeding breaths unfold the
lungs more and more, until finally the air-sacs and bronchioles
are all opened up and filled with air. The lungs thus once filled
with air are never completely emptied again until after death.
The air remaining in the lungs after expiration is called the
old or stationary air, into which fresh air is introduced with
every inspiration, the fresh or tidal air, as it is called, giving
up its oxygen to, and taking carbonic acid from, the old or
stationary air. Thus the stationary air transacts the business
of respiration, receiving, on the one hand, constant supplies of
oxygen from the tidal air which it delivers to the blood in the
capillaries on the walls of the air-sacs ; and, on the other hand,
returning, in exchange to the tidal air, the carbonic acid it has
received from the blood in these capillaries.
In ordinary respiration the lungs are not distended to their
fullest extent, but by more forcible muscular contraction the
capacity of the chest can be further enlarged, and a certain
additional amount of air will rush into the lungs. This addi-
tional amount is often spoken of as complemental air. In
laboured breathing the contraction of the respiratory muscles
not usually brought into play, such as the muscles of the throat
and nostrils, becomes very marked.
The entry and exit of the air are accompanied by respiratory
sounds or murmurs. These murmurs differ as the air passes
through the trachea, the larger bronchial tubes, and the bron-
chioles. They are variously modified in lung disease, and are
then often spoken of under the name of " rales."
The effects of respiration upon the air outside the body. — With
every inspiration a well-grown man takes into his lungs about
thirty cubic inches of air. The air he takes in differs from the
air he gives out mainly in three particulars : —
1. Whatever the temperature of the external air, the expired
air is nearly as hot as the blood; namely, of a temperature
between 98°' and 100° F.
138 ANATOMY FOR, NURSES. [CHAP. XII.
2. However dry the external air may be, the expired air is
quite, or nearly, saturated with moisture.
3. The expired air contains about four or five per cent less
oxygen, and about four per cent more carbonic acid than the
external air, the quantity of nitrogen suffering but little change.
Thus: —
Oxygen. Nitrogen. Carbonic Acid.
Inspired air contains . . . 20.81 79.15 0.04
Expired air contains . . . 16.033 79.587 4.38
(Foster.)
In addition the expired air contains a certain amount of effete
matter, of a highly decomposable and impure character. The
quantity of water given off in twenty-four hours varies very
much, but may be taken on the average to be about nine ounces.
The quantity of carbon given off at the same time is pretty
nearly estimated by a piece of pure charcoal weighing eight
ounces.
If a man breathing fifteen to sixteen times a minute takes in
thirty cubic inches of air with each breath, and exhales the
same quantity, it follows that in twenty-four hours from three
hundred and fifty to four hundred cubic feet of air will have
passed through his lungs. And if such a man be shut up in a
close room measuring seven feet each way, all the air in the
room will have passed through his lungs in twenty-four hours.
Since at every breath the external air loses oxygen and gains
carbonic acid and other waste and poisonous matters, it is
imperative that some provision be made for constantly renewing
the atmospheric surroundings of people in dwelling houses.
This is accomplished by ventilation, which consists of a system
of mechanical contrivances, by means of which foul air is con-
stantly removed and fresh air as constantly supplied.
The minimum amount of air space every individual should
have to himself is 800 cubic feet (a room nine feet high, wide,
and long contains 729 cubic feet) and this space should be
accessible by direct or indirect channels to the outside air.
Effects of respiration upon the blood. — While the air in passing
into and out of the lungs is robbed of a portion of its oxygen
and loaded with a certain quantity of carbonic acid, the blood
as it streams along the pulmonary capillaries is also undergoing
important changes. As it leaves the right ventricle it is venous
CHAP. XII.] RESPIRATION.
blood of a dark purple colour ; when it enters the left auricle it
is arterial blood and of a bright scarlet colour. In passing
through the capillaries of the body from the left to the right
side of the heart it is again changed from the arterial to the
venous condition. The question arises, how is this change of
colour effected?
As we have already seen, the blood in the thin- walled, close-
set pulmonary capillaries is separated from the air in the air-
sacs by only the' moist delicate membranes which form their
respective walls. By diffusion the oxygen in the air passes
through these moist membranes into the venous blood in the
pulmonary capillaries, combines with the reduced haemoglobin
which has lost its oxygen in the tissues, and turns it into oxy-
haemoglobin ; the purple colour shifts immediately into scarlet,
and the red corpuscles hasten onwards to carry this oxy-haemo-
globin to the tissues. Passing from the left ventricle to the
capillaries in the tissues the oxy-haemoglobin gives up some of
its oxygen, the colour shifts back again to a purple hue, and
the red corpuscles return with this reduced haemoglobin to the
lungs.
The oxygen given up by the blood combines with the ele-
ments of the tissues and forms with them unstable chemical
compounds which are always breaking down to form more sta-
ble compounds, called " oxides." In this process, which is called
oxidation, both heat and force are produced and such oxidized
products as carbonic acid and urea are evolved.1 The carbonic
acid passes by diffusion into the venous blood, and is carried by
it to the right side of the heart and thence to the lungs, a
certain quantity, however, escaping from the blood through the
kidneys and skin. A small and insignificant amount of oxygen
is introduced into the blood through the skin, and, with the
food, through the alimentary canal ; but, as we have stated in
the beginning of this chapter, respiration is the main process by
means of which the body is supplied with oxygen and relieved
of carbonic acid.
The respiration and circulation are profoundly and intimately
1 This process of oxidation may be illustrated by the burning of a fire ; the
oxygen which is in the air combines with the carbon of the wood, heat and light
are generated, and oxidized products in the form of carbonic acid and ashes pro-
duced.
140 ANATOMY FOE NURSES. [CHAP. XII.
connected together, any change in the blood immediately affect-
ing the respiration.
It would appear that stimulation of the respiratory centre in
the medulla oblongata depends primarily upon the condition of
the blood. If the blood is very rich in oxygen the respirations
are feeble and shallow ; if, on the other hand, the blood is highly
venous the respirations are deeper and more frequent, and if the
blood remains venous, gradually become forced and laboured
until we get the condition called " dyspnoea." Should the blood
get more and more venous, the impulses generated in the respir-
atory centre become more and more vehement. These nervous
impulses, instead of confining themselves to the usual nerves
distributed to the ordinary respiratory muscles, overflow on to
other nerves and put into action other muscles until there is
scarcely a muscle in the body that is not affected. The muscles
which are thus more and more thrown into action are especially
those tending to carry out or to assist expiration ; and at last if
no relief is afforded the violent respiratory movements give way
to general convulsions of the whole body. By the violence of
these convulsions the whole nervous system becomes ex-
hausted, the convulsions soon cease, and death is ushered in
with a few infrequent and long-drawn breaths.
It has been surmised that the excitability of the respiratory
nerve-centre is due to certain chemical substances which act as
stimulants. When the blood is rich in oxygen this substance is
oxidized or burned, and removed so fast that it is able to exert
but little influence on the respiratory nerve-centre ; when, how-
ever, the blood is poor in oxygen, this substance accumulates
and the nerve-centre is powerfully stimulated. Thus when the
'blood needs oxygen, the respirations are increased to get, if
possible, more air into the lungs ; if the blood is too rich in
oxygen, the respirations become abnormally quiet and shallow.
Modified respiratory movements. — Various emotions may be
expressed by means of the respiratory apparatus.
Sighing is a deep and long-drawn inspiration, chiefly through
the nose.
Yawning is an inspiration, deeper and longer continued than
a sigh, drawn through the widely open mouth, and accompanied
by a peculiar depression of the lower jaw.
Hiccough is caused by a sudden, inspiratory contraction of the
CHAP. XIL] RESPIRATION. 141
diaphragm ; the glottis suddenly closes and cuts off the column
of air just entering , which, striking upon the closed glottis,
gives rise to the characteristic sound.
In sobbing, a series of convulsive inspirations follow each
other slowly, the glottis is closed, so that little or no air enters
the chest.
Coughing consists, in the first place, of a deep and long-drawn
inspiration by which the lungs are well filled with air. This is
followed by a complete closure of the glottis, and then comes a
forcible and sudden expiration, in the midst of which the glottis
suddenly opens, and thus a blast of air is driven through the
upper respiratory passages.
In sneezing, the general movement is the same, except that
the opening from the pharynx into the mouth is closed by the
contraction of the pillars of the throat and the descent of the soft
palate, so that the force of the blast is driven entirely through
the nose.
Laughing consists essentially in an inspiration, followed by a
whole series of short spasmodic expirations, the glottis being
freely open during the whole time, and the vocal cords being
thrown into characteristic vibrations.
In crying, the respiratory movements are the same as in
laughing ; the rhythm and the accompanying facial expressions
are, however, different, though laughing and crying often be-
come indistinguishable.
CHAPTER XIII.
ALIMENTATION.
SECTION I. Preliminary remarks on secreting glands and mucous
membranes.
SECTION II. Food-principles ; proteids, fats, carbo-hydrates, water, saline
and mineral substances : chemical composition of the body : average compo-
sition of rnilk, bread, and meat. Concluding remarks.
SECTION I. In our last chapter, we described the methods by
means of which the blood was supplied with its most vital con-
stituent, oxygen. In the next three chapters, we shall consider
how the blood is supplied with those materials through the ali-
mentary canal, which it also constantly requires to maintain the
life and growth of the body.
The subject of alimentation, or the process by which the
body is nourished, naturally falls into three divisions, viz. : —
(1) Food.
(2) Digestion.
(3) Absorption.
In order, however, to make the subject more intelligible, it
will be necessary to make a few preliminary remarks upon the
construction of secreting glands and mucous membranes.
Secreting glands. — The secreting glands differ from other
glands, such as the lymphatic glands, the tonsils, Peyer's
patches, etc., by being always devoted to the function of
secretion, and by discharging the secretions they form through
little tubes or ducts which open exteriorly. The lymphatic
glands and bodies of allied structure are often spoken of as
ductless glands, in order to distinguish them from these true
secreting glands provided with ducts.
A secretion is a substance elaborated from the blood by cell
142
CHAP. XIII.]
ALIMENTATION.
143
action, and poured out upon the external or internal surfaces
of the body. An excretion resembles a secretion, except that
whereas the secretion is formed to perform some office in the
body, the excretion is formed only to be thrown out of the
body.
A secretory apparatus consists essentially of a layer of secret-
ing cells placed in close communication with a network of
blood-vessels. The simplest form in which a secretory appa-
FIG. 93. — DIAGRAM SHOWING THE VARIOUS FORMS OF SECRETING STRUCTURES.
A, general plan of a secreting membrane ; 6, basement membrane, with cells (a) on one
side and blood-vessels (c) on the other; B and E, simple tubular, saccular, and
coiled tubular glands ; C, compound tubular gland ; D, compound saccular, or race-
mose gland.
ratus occurs is in the shape of a plain, smooth surface, com-
posed of a single layer of epithelial cells, resting usually on a
thin membrane, on the under surface of which is spread out a
close network of blood-vessels. In order to economize space
arid to provide a more extensive secreting surface, the mem-
brane is generally increased by dipping down and forming vari-
ously shaped depressions or recesses, these depressions or recesses
being called the secreting glands.
The secreting glands are of two kinds, simple and compound.
The simple glands are generally tubular or saccular cavities, the
tube in the tubular variety being sometimes so long that it coils
upon itself, as in the sweat glands of the skin ; they all open
upon the surface by a single duct. In the compound glands,
the cavities are subdivided into smaller tubular or saccular
cavities, opening by small ducts into the main duct which pours
the secretion upon the surface.
However simple or complicated the involuted surface, the
secreting process is essentially the same ; and in this process
the nucleated cells play the most important part. These cells
take into their interior those substances from the blood which
they require to make the special secretion they are set apart to
144 ANATOMY FOR NUKSES. [CHAP. XIII.
form, converting this selected material into chemical com-
pounds, which either act as solvents, as in the digestive juices,
or perform some other office in the body. The secretion the
cells elaborate escapes from them either by exudation or by the
bursting and destruction of the cells themselves. Cells filled
with secreting matter may also be detached and carried out
entire with the fluid part of the secretion ; and, in all cases,
new cells speedily take the place of those which have served
their office. The glands are provided with lymphatics, and fine
nerve fibrils have also been found to terminate in them. That
they are under the influence of the nervous system is shown by
the fact that impressions made on the nervous system affect
the secretions, a familiar instance of which is the flow of saliva
into the mouth, caused by the sight, or smell, or even the
thought of food.
The position and functions of the several glands will be de-
scribed later in connection with digestion and elimination.
Mucous membranes. — The mucous membranes, unlike the
serous membranes, line passages and cavities which communi-
cate with the exterior. They are all subject to the contact
of foreign substances introduced into the body, such as air
and food, and also to the contact of secreted matters ; hence
their surface is coated over and protected by mucus, a thicker
and more sticky fluid than the lymph which moistens the
serous membranes. The mucous membranes of different parts
are continuous, and they may nearly all be reduced to two great
divisions ; namely, the gastro-pneumonic and the genito-urinary.
The gastro-pneumonic mucous membrane covers the inside
of the alimentary canal, the air-passages, and the cavities com-
municating with them. It commences at the edges of the lips
and nostrils, proceeds through mouth and nose to the throat,
and thence is continued throughout the entire length of the
alimentary canal to the anus. At its origin and termination
it is continuous with the external skin. It also extends
throughout the windpipe, bronchial tubes, and air-sacs. From
the interior of the nose the membrane may be said to be pro-
longed into the lachrymal passages, and under the name of
conjunctival membrane, over the fore part of the eyeball and
inside of the eyelids, on the edges of which it again meets with
the skin. From the upper part of the pharynx a prolongation
CHAP. XIII.] ALIMENTATION. 145
extends, on each side, along the passage to the ear ; and off-
sets in the alimentary canal go to line the salivary, pancreatic,
and biliary ducts, and the gall-bladder.
The genito-urinary mucous membrane lines the inside of the
bladder, and the whole urinary tract from the interior of the
kidneys to the meatus urinarius, or orifice of the urethra; it
also lines the vagina, uterus, and Fallopian tubes in the female.
The mucous membranes are attached to the parts beneath
them by areolar tissue, here named " submucous," and which
differs greatly in quantity as well as in consistency in different
parts. The connection is in some cases close and firm, as in
the cavity of the nose. In other instances, especially in cavities
subject to frequent variations in capacity, like the gullet and
stomach, it is lax ; and when the cavity is narrowed by con-
traction of its outer coats, the mucous membrane is thrown into
folds or rugce which disappear again when the cavity is dis-
tended. But in certain parts the mucous membrane forms
permanent folds that cannot be effaced, and which project con-
spicuously into the cavity which it lines. The best marked
example of these folds is seen in the small intestine, where
they are called valvulce conniventes, and which are doubtless
provided for increasing the amount of absorbing surface for the
products of digestion. The redness of mucous membranes is
due to their abundant supply of blood.
A mucous membrane is composed of a layer of connective
tissue called the corium, and by a layer of epithelium which
covers the surface. The epithelium is the most constant part of
a mucous membrane, being continued over certain parts to which
the other parts of the membrane cannot be traced, as over the
air-sacs in the lungs, and the front of the cornea of the eye.
It may be scaly and stratified, as in the throat, columnar, as in
the intestine, or ciliated, as in the respiratory tract. The
mucus which moistens its surface is either derived from little
glands in the mucous membrane, or from the columnar cells
which cover the surface. The corium of a mucous membrane
is composed of either areolar or lymphoid connective tissue.
It is usually bounded next to the epithelium by a basement
membrane,1 and next to the submucous tissue by a thin
1 A basement membrane is formed by a layer of connective tissue cells joined
edge to edge.
146
ANATOMY FOE, NURSES. [CHAP. XIII
layer of plain muscular tissue termed the mmcularis mucosce'.
this layer is not always present. The connective tissue layei
varies much in structure in different parts ; the lymphoid
variety is in certain places greatly increased in amount, packed
with lymphoid cells, and forms the solitary follicles and
Peyer's patches described in Chapter XII.
The small blood-vessels conveying blood to the mucous mem-
branes divide in the sub-mucous tissue, and send smaller branches
into the corium, where they form a network of capillaries just
under the basement membrane. The lym-
phatics also form networks in the corium
and communicate with larger vessels in the
sub-mucous tissue below. The free surface
of the mucous membrane is in some parts
plain, but in others is beset with little emi-
\OL nences named papillae and villi.
The papillae are best seen on the tongue ;
they are small processes of the corium,
mostly of a conical shape, containing blood-
vessels and nerves, and covered with epi-
thelium.
The villi are most fully developed on the
mucous coat of the small intestine. Being
> c ^ set close together like the pile of velvet,
FIG. 94. -AN INTES- the^ &ive a sha^^ or villous appearance
VILLUS. a, a, a, to the membrane. They are little projec-
tions of the mucous membrane, covered with
c, c, longitudinal muscle epithelium, and containing blood-vessels
fibres ;d, lacteal vessel. au(j lacteal^ ftnd are favourably arranged
for absorbing nutritive matters from the intestines.
SECTION II. Food. — Under the term "food" we include all
substances, solid or liquid, necessary for nutrition. The ques-
tion at once arises: What are these substances, and how are
they obtained?
If we analyze the food we daily take into our mouths and
introduce into the alimentary canal, we find it separable into
two divisions ; viz. that which is nutritious, and that which
is innutritions. The nutritious portion, that which can be
digested, absorbed, and made use of by the body, is generally
spoken of under the name of food-stuffs or food-principles: the
CHAP. XIIL] ALIMENTATION. 147
innutritious portion, usually by far the smaller of the two divis-
ions, never enters the body at all, properly speaking, but passes
through the alimentary canal and is excreted in the form of
feces.
Food-stuffs are composed mainly of the elementary chemical
substances, — oxygen, carbon, hydrogen, nitrogen, — and may,
according to the varying proportions in which these chemical
elements combine, form five distinct and different classes of
food-stuffs. These are : —
1. Proteids.
2. Fats.
3. Carbo-hydrates.
4. Water.
5. Saline or mineral matters.
Proteids. — Proteids form a large proportion of all living
bodies, and are an essential part of all living structures. They
contain on an average in every 100 parts about : —
Carbon 53 parts
Hydrogen 7 "
Oxygen 24 "
Nitrogen 16 "
with usually a little sulphur and sometimes a trace of phos-
phorus and iron. They are the only food-stuffs that contain
nitrogen in any appreciable quantity, and are sometimes
classed as " nitrogenous " food-stuffs. Proteids occur in the
form of albumin in the white of egg (egg-albumin), in milk,
in blood and lymph (serum-albumin); in the form of casein in
milk and cheese ; of myosin and syntonin in muscle ; of vitellin in
the yolk of eggs ; of glutin in flour. Allied to proteids are the
chondrin, obtained from cartilage, and the gelatin, obtained
from other varieties of connective tissue, by boiling.
All proteids yield peptones very readily at the temperature
of the body under the action of the acid gastric, and alka-
line pancreatic juice. These peptones are highly soluble bodies
and readily absorbed.
The foods that are most rich in the various forms of proteids
are meat, milk, eggs, cheese, all kinds of fish, wheat, beans,
and oatmeal.
148 ANATOMY FOR NURSES. [CHAP. XIII.
Fats. — Fats are composed of carbon, hydrogen, and oxygen.
They contain on an average in every 100 parts : —
Carbon 76.5 parts
Hydrogen 12 "
Oxygen 11.5 "
The most important fats are stearin, palmatin, margarin, and
olein, which exist in varying proportions in the fat of animals
and vegetable oils, and in milk, butter, lard, etc. The brains of
animals and the yolk of eggs contain a complex phosphorized
fat, called lecithin. Fatty matters are very abundant in olives,
sweet almonds, chocolate, castor-oil bean, hemp, and flaxseed.
Most of the fatty substances of food are liquefied at the tem-
perature of the body, and are readily oxidized, probably on
account of the large amount of carbon which they contain.
Carbo-hydrates. — In the carbo-hydrates there is sufficient
oxygen present to saturate all the hydrogen and to form water;
hence their name. In the fats, there is not quite so much
oxygeA as hydrogen ; water is, therefore, not formed in them,
and in this particular they differ from the carbo-hydrates.
The carbo-hydrates contain in every 100 parts about : —
».
Carbon 44 parts
Hydrogen ." \ ' . . . 6 ""*•
Oxygen 50 "
The principal carbo-hydrates are starch and sugars. Starch is
found in wheat, Indian corn, oats, and all grains, in potatoes,
peas, beans, roots and stems of many plants, and in some fruits.
In a pure state, it appears as a white powder, as in arrowroot
and cornstarch. Under the influence of dry heat, starch may
be converted into a soluble substance, called dextrine; and,
under the action of certain of the digestive juices, at the tem-
perature of the body, into sugar. Of sugars there are several
kinds : cane sugar or sucrose, obtained chiefly from the sugar
cane, beet sugar, and maple sugar; grape sugar or glucose, found
in grapes, peaches, and other fruits (it is also readily manufact-
ured from starch) ; milk sugar or lactose, obtained from milk.
Carbo-hydrates are readily oxidized ; together with fats, they
are often classed as " non-nitrogenous " food-stuffs.
Water is a compound of oxygen and hydrogen, water being
CHAP. XIII.] ALIMENTATION. 149
produced whenever two molecules of hydrogen unite with one
of oxygen. Next to air, water is the most necessary principle
of life. It forms about seventy per cent of the entire bodily
weight. It is an essential constituent of all the tissues, as
well as forming the chief part of all the fluids of the body.
It acts as a solvent upon various ingredients of the food, lique-
fying them and rendering them capable of absorption. Most
of the water of the body is taken into it from without, but it is
also formed within the body by the union of hydrogen and
oxygen in the tissues.
Mineral salts. — The mineral substances chiefly necessary for
nutrition are : —
Chloride i
Phosphate
0 ^ f [ot soda and potash.
Sulphate
Carbonate J
Phosphate ~i _ , .
~ , \ of lime and magnesia.
Carbonate J
Of these substances, chloride of soda, sodium chloride or common
salt, is the most important mineral ingredient of food. It is
contained in nearly everything we eat, but usually not in suffi-
cient quantity to supply all the needs of the body, and we
therefore add it as a separate article of diet. It is present in
most of the fluids of the body, notably in the blood, the fluidity
of which it helps to maintain. The rest of the mineral sub-
stances are usually contained in sufficient quantity in an ordi-
nary diet, though occasionally it becomes necessary to supply
them independently. Of all the mineral salts, phosphate of lime
exists in the largest quantity in the body ; it enters largely into
the composition of the bones, teeth, and cartilages, and gives
firmness and solidity to the tissues. It is present in very
small quantities in the bodily fluids, with the exception of
milk, which contains a notable amount of phosphate of lime,
and which is plainly provided for the ossification of the grow-
ing bones of infants and young children.
Chemical composition of the body. — Professor Atwater gives
the following average composition of the body of man, weigh-
ing 148 pounds : —
150 ANATOMY FOR NURSES. [CHAP. XIII.
142.9
Carbon
Hvdrosren
.... 31.3
.... 14.6
Nitrogen
.... 4.6
Calcium
. . . ' 28 )
Phosphorus ....
1 4
Potassium
34
Sulphur
24
Chlorine
12
Sodium
12
Magnesium
04
Iron
... 02
Fluorine .
.02
5.1
The human body, from a chemical point of view, may be
regarded as a compound of three large classes of chemical sub-
stances ; viz. proteids, fats, and carbo-hydrates associated with
water and mineral salts.
In our first chapter we said that protoplasm was the basis of
the life of the body, and from that point of view we may look
upon the human body as an assemblage of variously modified
protoplasm. But it comes to the same thing, for the chemical
composition of protoplasm, so far as it has been possible to
analyze it, has been found to agree closely with that of the
fully developed organism.
The processes of nutrition that take place in the protoplasmic
cell are essentially the same as those which take place in the
fully developed body, with this exception, that in the one case it
is a very simple, and in the other a very complex, process. In
both cases, non-living chemical substances are taken in from
without, and converted into material which is endowed with
that mysterious property we call life.
To support life, the different food-stuffs must be taken in
proper proportion ; and, in order that -all the tissues and fluids
of the body may continue in good condition and perform their
functions properly, they must be supplied with all the ingredi-
ents necessary to their constitution. A man may be starved to
death at last by depriving him of lime phosphate as surely,
though not as rapidly, as if he were deprived of albumin or fat.
Many a patient in less well-instructed times has been slowly
killed by deprivation of water, or by exclusive feeding on beef-
teas and jellies.
CHAP. XIII.] ALIMENTATION.
151
Average composition of milk, bread, and meat. — The following
analyses of the composition of three staple articles of diet
milk, bread, and meat — are taken from Dalton.
Average composition of milk in 100 parts : —
Water 35,4
Proteids 43
Sugar 52
Fat 3.7
Mineral salts 4
Average composition of wheaten bread in 100 parts :
Starchy matters 56.7
Proteids 7.0
Fatty matters - 1.3
Mineral salts 1.0
Water 34.0
Average composition of beef flesh : —
Water 77.5
Proteids 16.0
Fat 5.0
Mineral salts 1.5
Concluding remarks. — The quantity and also the kind of food
each individual daily requires depends chiefly upon the nature
and the amount of the work he is called upon to perform, and
the conditions of the climate in which he lives. Universal
experience has taught us that the best sustainers of life are
milk and bread and water, with a certain amount of meat and
fat. These should form the basis of all our diets, though not
to the exclusion of other food-stuffs, for it has also been proved
that a mixed diet is always to be preferred to one that consists
constantly of the same articles of food.
To determine the relative digestibility of foods is a very diffi-
cult matter in view of the individual peculiarities of different
people. Strawberries may agree perfectly with ninety-nine
people, and with the hundredth, act as a powerful poison.
Some persons, as we all know, cannot tolerate milk or eggs,
and yet, from a chemical point of view, these foods are emi-
nently suitable articles of diet.
The best diet is that which contains all the articles of food
152 ANATOMY FOR NURSES. [CHAP. XIII.
necessary for the wants of the body in proper proportions, which
is agreeable to the individual, and which gives the minimum
amount of work to the digestive organs.1
Food to be of any use to the body must be digested and
assimilated. We may partake of an ideal diet and yet remain
imperfectly nourished, if our digestive organs are out of order,
or our power to absorb and assimilate digested products in any
way impaired. In our next chapter we shall describe the ali-
mentary canal, the accessory digestive organs, and the methods
by means of which the food is reduced to a condition available
for the uses of the body.
1 For valuable information on the relative value of foods and preparation of
the same for the sick, the student is referred to Eoland's " Handbook of Invalid
Cookery."
CHAPTER XIV.
ALIMENTATION CONTINUED : THE DIGESTIVE APPARATUS ; ALI~
MENTARY CANAL, AND ACCESSORY ORGANS.
THE digestive apparatus consists of the alimentary canal, and
the accessory organs, the teeth, salivary glands, pancreas, and
liver. By some authorities the spleen is also now included
among the digestive organs.1
Alimentary canal. — The alimentary canal is a musculo-mem-
branous tube extending from the mouth to the anus. It is
about six times the length of the body, and the greater part of
it is coiled up in the cavity of the abdomen. The diameter of
the tube is by no means uniform, being considerably dilated in
certain parts of its course. It is composed of three coats from
the mouth to where it passes through the diaphragm, and of
four coats in the abdominal cavity. These coats are : (1) the
mucous ; (2) the sub-mucous (described in our last chapter) ;
(3) the muscular ; (4) the serous. The muscular coat is com-
posed for the most part of unstriped muscular fibres, the layers
of which are disposed in various ways, the most general arrange-
ment being in a longitudinal and circular direction. By the
alternate contraction and relaxation of fibres arranged in this
fashion (the contractions starting from above), the contents of
the tube are propelled from above downwards. The serous coat
is derived from the peritoneum, which is the serous membrane
lining the walls, and covering the viscera, of the abdomen.
Into the interior of the alimentary canal are poured secre-
tions from the glands in the mucous membrane, with which it is
lined, and also secretions from the accessory glands, which lie
outside the canal and are connected with its interior by ducts.
The alimentary canal for convenience of description may be
divided into : —
1 Plate VII. shows relative position of digestive organs in abdominal cavity.
153
PLATE VII. — REGIONS OF THE ABDOMEN AND THEIR CONTENTS (EDGE OP COSTAL
CARTILAGES IN DOTTED OUTLINE).
For convenience of description the abdomen may be artificially divided into nine
regions by drawing two circular lines round the body parallel with the cartilages of
the ninth ribs, and the highest point of the crests of the ilia ; and two vertical lines
from the cartilage of the eighth rib on each side to the centre of Poupart's ligament.
The viscera contained in these different regions are as follows : —
RIGHT HYPOCHONDRIAC. —
The right lobe of the liver and
the gall-bladder, hepatic flexure
of the colon, and part of the
right kidney.
EPIGASTRIC REGION. — The
middle and pyloric end of the
stomach, left lobe of the liver,
the pancreas, the duodenum,
parts of the kidneys and the
suprarenal capsules.
LEFT HYPOCHONDRIAC. — The
splenic end of the stomach, the
spleen and extremity of the pan-
creas, the splenic flexure of the
colon, and part of the left kid-
ney.
RIGHT LUMBAR. — Ascend-
ing colon, part of the right kid-
ney, and some convolutions of
the small intestines.
UMBILICAL REGION. — The
transverse colon, part of the
great omen um and mesentery,
transverse part of the duode-
num, and some convolutions of
the jejunum and ilium, and
part of both kidneys.
LEFT LUMBAR. — Descending
colon, part of the omentum,
part of the left kidney, and
some convolutions of the small
intestines.
RIGHT INGUINAL (ILIAC). —
The ca-cum, appendix cifcci.
HYPOGASTRIC REGION. — Con-
volutions of the small intes-
tines, fix- bladder in children,
and in adults if distended, and
the uterus during pregnancy.
LEFT INGUINAL (ILIAC). —
Sigmoid flexure of the colon.
154
CHAP. XIV.]
ALIMENTATION.
155
Mouth, containing tongue and teeth.
Pharynx.
(Esophagus.
Stomach.
Duodenum.
Small intestine
Jejunum.
Ilium.
f Caecum.
Large intestine j Colon.
I Eectum.
Mouth or buccal cavity (vide Fig. 96). — The mouth is a nearly
oval-shaped cavity with a fixed roof and movable floor. It is
bounded in front by the lips, on the sides by the cheeks, below
by the tongue, and above by the palate. The palate con-
sists of a hard portion
in front formed by
bone, covered by mu-
cous membrane, and
cf a soft portion be-
hind containing no
bone. The hard palate
forms the partition
between the mouth
and nose ; the soft
palate arches back-
wards and hangs like
a curtain between the
mouth and the phar-
ynx. Hanging from
the middle of its lower
border is a pointed
portion of the soft pal-
ate called the uvula ;
and arching outwards and downwards from the base of the
uvula on each side to the roof of the tongue are two curved
folds of muscular tissue covered by mucous membrane, called
the pillars of the fauces. Just before reaching the tongue,
the two pillars, on either side, are separated by a triangular
space in which lie the small masses of lymphoid tissue called
the tonsils. The fauces is the name given to the aper-
FIG. 95. — THE SALIVARY GLANDS.
156 ANATOMY FOR N URSES. [CHAP. XIV.
ture leading from the mouth into the pharynx or throat
cavity.
The mucous membrane lining the mouth contains many
minute glands which pour their secretion upon its surface, but
the chief secretion of the mouth is supplied by the salivary
glands, which are three pairs of large compound saccular glands 1
called the parotid, submaxillary, and sublingual, respectively.
Each parotid gland is placed just in front of the ear, and its duct
passes forwards along the cheek, until it opens into the interior
of the mouth opposite the second upper molar.
The submaxillary and sublingual glands are situated below
the jaw and under the tongue, the submaxillary being placed
further back than the sublingual. Their ducts open in the
floor of the mouth beneath the tongue. The secretion of these
salivary glands, mixed with that of the small glands of the
mouth, is called saliva.
The tongue. — The tongue is a freely movable muscular organ
attached by its base to the hyoid bone. Besides being the
special seat of the sense of taste, it is a useful aid in mastication
and deglutition.2
The teeth. — The semicircular borders of the upper and lower
jaw-bones (the alveolar processes) contain thirty-two sockets for
the reception of the teeth ; extending over the bones and a little
way into each socket is a dense insensitive fibrous tissue covered
by smooth mucous membrane, the gums.
There are two sets of teeth developed during life : the first
or milk teeth, and the second or permanent teeth. The cutting
of the milk teeth begins usually at six months and ends with
the second year ; there are only twenty of these teeth, and they
are replaced during childhood by the permanent teeth.3
Each tooth consists of two portions, the crown and the fang :
the crown projects into the cavity of the mouth, the fang is
embedded in the socket. According to their shape and the use
teetli are divided into incisors, canines, bicuspids, and molars.
1 For description of compound glands see Section I. Chapter XIV.
2 A detailed description of the tongue will be found in the chapter on the
organs of special sense.
a The milk teeth are usually cut in the following order, the teeth appearing
first in the lower jaw: central incisors, 7th month ; lateral incisors, 7th to 10th
month ; front molars, 12th to 14th month ; canine, 14th to 20th month ; back
molars, 18th to 36th month.
CHAP. XIV.]
ALIMENTATION.
157
Beginning in the middle line of each jaw and counting from
before backwards, there are four incisors, two canines, four
bicuspids, and six molars in the upper and in the lower jaw.
The incisors have wide sharp edges, and are specially adapted
for cutting the food ; the canines, or eye teeth, have a sharp
pointed edge, are longer than the incisors, and are specially
useful for tearing food asunder,
or, as in dogs and other car-
nivora, for holding prey. The
bicuspids, or false grinders, are
broader, with two points or cusps
on each crown : these teeth have
only one fang, the fang, however,
being more or less completely
divided into two. The molars,
or true grinders, have broad
crowns with small pointed pro-
jections, which make them well
fitted for crushing and bruising
the food : they each have two or
three fangs. The twelve molars
do not replace the milk teeth, but
are gradually added with the
extension of the jaws, the last or
hindermost molars not appearing
until twenty-one years of age:
777,
FlG. «,._!„,, MOUTH, NOSE
they are often on this account PHARYNX, WITH THE LAKYNX AND
"wisdom fppth "
Cl1'
The
COMMENCEMENT OF GULLET, SEEN
IN SECTION, a, vertebral column ; 6,
teeth are composed of gullet; c, trachea; d, larynx; e, epi-
three bone-like tissues, enamel, tt'&'XEfSttZ
dentine, and cement; these Sub- fauces; <?, opening of Eustachian tube;
-•1 -i j ,-1 i h, nasal cavity; k, tongue; /, hard
stances are all harder than bone, palate; m> sphenoid bone at base of
enamel being the hardest tissue skull; n, roof of nasal cavity ; o,p, q,
j, ,. ,, ,, T j i -A placed in nasal cavity.
found in the body. In the inte-
rior of each tooth is a cavity, the pulp-cavity, which is filled
with a highly vascular and nervous tissue called the dental pulp.
The teeth are developed from epithelium in much the same way
as the hairs; for description of which see page 192.
The pharynx. — The pharynx or throat cavity is a musculo-
membranous bag, shaped somewhat like a cone, with its broad
158 ANATOMY FOR NUKSES. [CHAP. XIV.
end turned upwards, and its constricted end downwards to
end in the O3sophagus. It is about four and a half inches
long, and lies behind the nose, mouth, and larynx. Above, it
is connected with the base of the skull, and behind, with the
cervical vertebrae ; in front and on each side are apertures
which communicate with the nose, ears, mouth, and larynx.
Of these apertures there are seven : two in front above, lead-
ing into the back of the nose, the posterior nares ; two, one on
either side above, leading into the Eustachiari tubes, which com-
municate with the ears ; one midway in front, the fauces ; and
two below, one opening into the larynx and the other into the
oesophagus. The mucous membrane lining the pharynx is well
supplied with glands, and at the back of the cavity there is a
considerable mass of lymphoid tissue. The muscular tissue in
the walls of the pharynx is of the striped variety, and when the
act of swallowing is about to be performed the muscles draw
the pharyngeal bag upwards and dilate it to receive the food ;
they then relax, the bag sinks, and other muscles contracting
upon the food, it is pressed downwards and onwards into the
oesophagus.
The oesophagus or gullet. — The oesophagus is a comparatively
straight tube, about nine inches long, extending from the
pharynx, behind the trachea, and through the diaphragm, to
its termination in the upper or cardiac end of the stomach.
The muscular fibres in the walls of the oesophagus are arranged
in an external longitudinal and in an internal circular layer.
The mucous membrane is disposed in longitudinal folds which
disappear upon distension of the tube. The mucous mem-
brane in the mouth, pharynx, and oesophagus is covered for
the most part by stratified epithelium.
The stomach. — The stomach is the most dilated portion of
the alimentary canal. It is curved upon itself, so that below it
presents a long, rounded outline, called the greater curvature,
and above a constricted, concave outline, called the lesser
curvature.
It is placed transversely in the abdominal cavity, immediately
beneath the diaphragm, the larger expanded end lying in con-
tact with the spleen, and the smaller end under the liver. The
stomach has necessarily two openings : the one leading into the
oesophagus is usually termed the cardiac aperture; the other,
CHAP. XIV.] ALIMENTATION. 159
leading into the small intestine, the pyloric. The pyloric aper-
ture is guarded by a kind of valve composed of circular mus-
cular fibres, which form a constricted ring projecting into the
pyloric opening. By this arrangement, the food is kept in
the stomach until it is ready for intestinal digestion, when the
circular fibres relax and allow it to pass.
When moderately distended, the stomach measures about
four inches vertically and twelve inches from side to side. It
has four coats. The^ outer serous coat is formed by a fold of
the peritoneum. The fold is slung over the stomach, in
much the same way as
we sling a towel over a
clothes-line, and covers it
before and behind. The
anterior and posterior
folds unite at the lower
border of the stomach
and form an apron-like
appendage, the omentum,
which covers the whole
of the intestines. The
omentum often contains
a large amount of fat. FlG 97._VERTICAL AND LoNGITUDINAL SEC-
The muscular COat of TION OF STOMACH AND DUODENUM. 1, cesopha-
i-t i ' i r gus, on its internal surface the folds or ruga? of
the stomach consists of fhe mucous membrane are shown; 2> c{Trd5ac
three layers of UHStriped orifice of stomach ; 5, lesser curvature ; <>, greater
-, ,. curvature; 8, rugae in interior of stomach; 9,
muscular tissue: an outer, pyloric orifice; 10> n> 13> interior of duodenum
formed of longitudinal showing valvulre conniventes ; 12, duct conveying
£, ., ,, ,. the bile and pancreatic juice into duodenum; 15,
fibres ; a middle, OI Cir- commencement of jejunum.
cular; and an inner, of
less well-developed, obliquely disposed fibres. The alternate
contraction and relaxation of these fibres causes the food to
be carried round and round the stomach, and at the same time,
subjects it to considerable pressure.
The mucous membrane is very soft and thick, the thickness
being mainly due to the fact that it is densely packed with small
tubular glands; it is covered with columnar epithelium, and in
its un distended condition is thrown into folds or rugae. The
surface is honeycombed with tiny shallow pits, into which the
ducts or mouths of the tubular glands open. The glands are
160
ANATOMY FOR NURSES.
[CHAP. XIV.
of two kinds, and secrete mucus, and the special secretion of
the stomach, the gastric juice. The stomach is supplied with
nerves from the sympathetic system, and also with branches
from the pneumogastric nerve, which comes from the cerebro-
spinal system.
The small intestine. — The small intestine fills the greater
part of the front of the abdominal cavity. It is about twenty
feet long, two inches wide at its gastric end, and narrows to
nearly one and a quarter inches where it
joins the large intestine. The small intes-
tine is divided by anatomists into three
portions. The first ten or twelve inches
is called the duodenum ; the succeeding
two-fifths, the jejunum; and the rest, the
ilium. The intestines are invested by a
fold of the peritoneum in much the same
way as the stomach. In this situation, the
fold of the peritoneum is called the me-
sentery, and between its two layers are
numerous blood-vessels, lymphatics, and
lymphatic glands.
The muscular coat of the small intestine
has only two layers : an outer, thinner and
longitudinal; and an inner, thicker and
. 6
circular.
xhe mucous coat is highly developed. In
ved
FIG. 98. — AN INTES-
TINAL VILLUS. a, a, a,
columnar epithelium;
6, 6, capillary network; ... -, i .
c, c, lymphoid tissue the tirst place it is largely increased by
fibfeS; *' bein£ arrange<l in permanent folds, the
valvulse conniventes (vide Fig. 97), which
project transversely into the interior of the tube. The onward
course of the food is delayed by being caught in the hollows
formed by these folds, and thus more thoroughly subjected to
the action of the digestive juices : this arrangement also affords
a larger surface for absorption. The valvulse conniventes are
not found in the beginning of the duodenum, but begin to
appear one or two inches from the pylorus ; about the middle
of the jejunum they begin to decrease in size, and in the lower
part of the ilium they almost entirely disappear.
Again, the surface of the mucous membrane is increased by
the finger-like projections which are so close set as to give a
CHAP. XIV.]
ALIMENTATION.
161
snaggy or velvety appearance to the membrane. These projec-
tions or villi, as they are termed, extend throughout the whole
length of the small intestine, and are especially provided for
purposes of absorption. Each villus is a portion of the mucous
membrane, and consists of an external layer of columnar cells
attached to a basement membrane, and a central mass of lym-
phoid tissue. In the centre of each villus is the rootlet of a
lacteal vessel, while under the basement membrane is a network
of capillaries. The blood-vessels and lymphatics of the villi
communicate with networks of both vessels in the sub-mucous
coat below. Besides these projections formed for absorption,
FIG. 99. — SECTION THROUGH THE LYMPHOID TISSUE OF A SOLITARY GLAND.
(Cadiat.) a, centre of the gland, with the lymphoid tissue fallen away; 6, epithe-
lium of mucous membrane ; c, c, villi, with epithelium partly broken away ; d, crypts,
or glands, of Lieberkiihn.
the mucous membrane is thickly studded with secretory glands ;
the larger number of these, found all over the surface of the
intestine, are called the glands or crypts of Lieberkiihn, while a
smaller number, found chiefly in the duodenum, are named the
duodenal or Brunner's glands. These glands are supposed to
secrete the intestinal juice, succus entericus.
Again, in the corium of the mucous coat the lymphoid tissue
is collected into numerous solitary glands or follicles, and into
groups of glands, the Peyer's patches, the functions of which
are not yet clearly understood.
162 ANATOMY FOR NURSES. [CHAP. XIV.
The large intestine. — The large intestine is about five feet
long, and from two and a half to one and a half inches wide ;
it extends from the ilium to the anus. It is divided into the
csecum, with the vermiform appendix, the colon, and the rectum.
The coBcum (ccecus, blind) is a large blind pouch at the com-
mencement of the large intestine. The small intestine opens
into the side wall of the large intestine about two and a half
inches above its — the large intestine's — commencement, the
caecum forming a cul-de-sac below the opening. Attached to
the lower end of the csecum is a narrow,
worm-like tube about the size of a lead-
pencil, the vermiform appendix. The
csecum and appendix lie just beneath
the front abdominal wall in the right
iliac region (vide Plate VII.). The open-
ing from the ilium into the large intes-
tine is provided with two large project-
ing lips of mucous membrane which
allow the passage of material into the
large intestine, but effectually prevent
the passage of material in the opposite
direction. These mucous folds form
what is known as the ilio-csecal valve.
FIG. 100. — C^CUM, SHOW-
ING ITS APPENDIX, ENTRANCE The colon may be subdivided into the
vUTVc'aLmT^Tom1: ascending, transverse, and descending
mencement of colon; 3, en- colon, and the sigmoid flexure. The
E£2£ 4. ^."^ ending portion runs up on the right
6, aperture of vermiform ap- side of the abdomen until it reaches
•rmappen.
left, and is continued straight across the abdomen as the trans-
verse colon until, reaching the left side, it turns abruptly and
passes downwards as the descending colon. Reaching the left
iliac region on a level with the margin of the crest of the ilium,
it makes a curve like the letter S, — hence its name of sigmoid
flexure, — and finally ends in the rectum. The rectum is from
six to eight inches long ; it passes obliquely from the left until
it reaches the middle of the sacrum, then it follows the curve
of the sacrum and coccyx, and finally arches slightly backwards
to its termination at the anus. The anal opening is guarded
by two circular muscles called, respectively, the internal and
external sphincters.
CHAP. XIV.] ALIMENTATION. 163
The large intestine has the usual four coats, except near its
termination, where the serous is wanting. The muscular coat,
along the caecum and colon, has a peculiar arrangement. The
longitudinal fibres are gathered up in three thick bands, and
these bands, being shorter than the rest of the tube, the walls are
puckered between them. The mucous coat possesses no villi or
valvulae conniventes, but is usually thrown into effaceable
folds, somewhat like those of the stomach. It contains nu-
merous glands, resembling the crypts of Lieberkiihn found in
the small intestine.
Accessory organs of digestion. — The accessory organs of diges-
tion are, the teeth and salivary glands (which have already
been sufficiently described), the pancreas, and the liver.
The pancreas. — The pancreas is a compound, secreting gland,
FIG. 101. — POSTERIOR VIEW OF PANCREAS. 1, pancreas; 2, pancreatic duct; 6,
opening of common duct, formed by union of pancreatic and choledochus ducts, into
duodenum; A, pyloric end of stomach; B, duodenum ; C, part of gall-bladder; D,
cystic duct ; E, hepatic duct ; F, choledochus duct.
closely resembling the salivary glands in structure, except that
the secreting cavities are saccular in the salivary glands, and
more distinctly tubular in the pancreas. The cavities are
grouped in lobules, each lobule having its own duct. The
lobules are joined together by connective tissue to form lobes,
and the lobes, united in the same manner, form the gland.
The small ducts open into one main duct, which, running
lengthwise through the gland, pierces the coats of the duo-
164 ANATOMY FOE NTJBSES. [CHAP. XIV.
denura and pours its contents into the interior of the intestine.
The secretion formed in the pancreas is called the pancreatic
juice.
In shape, the pancreas somewhat resembles a dog's tongue.
It is a flat, elongated organ, about six to eight inches in length,
one and a half inches in width, and from half an inch to an inch
thick. It lies beneath the greater curvature of the stomach and
at the back of the abdominal cavity.
The liver. — The liver is the largest gland in the body, weigh-
ing ordinarily from fifty to sixty ounces, and measuring ten to
twelve inches from side
to side, six to seven from
above downwards, and
three inches from before
backwards in its thickest
part. It is a dark red-
dish-brown organ, placed
in the upper right and
middle portion of the
abdomen, and extending
somewhat into the left
FIG. 102. —UNDER SURFACE OF LIVER. 1,
right lobe ; 2, left lobe ; 3, 4, 5, smaller lobes ; 9, 12, hypochondriac region,
inferior vena cava ; 10, gall-bladder ; 11, transverse rpi llrkrkOT> nrmArov c
fissure, or " gate of liver," containing bile duct, he- UPP6
patic artery, and portal vein. face fits closely into the
under surface of the
diaphragm. The under concave surface of the organ fits over
the right kidney, the upper portion of the ascending colon, and
the pyloric end of the stomach. The liver is unequally divided
into two lobes, the right being much larger than the left. It is
covered by a layer of peritoneum, and is also suspended and
kept in position by ligamentous peritoneal bands.
The liver not only differs in size from the other secreting
glands ; it also offers other striking peculiarities. First, it re-
ceives its supply of blood from two different sources ; namely,
arterial blood from the hypatic artery, and venous blood from
the stomach, spleen, pancreas, and intestines, by means of the
portal vein. Secondly, the different parts of the secretory
apparatus, the cells, blood-vessels, and ducts, instead of being
arranged as elsewhere in distinct tubes or sacs, are closely
united and massed together. The secreting cells are collected
CHAP. XIV.] ALIMENTATION. 165
into small polyhedral or many-sided masses, called hepatic
lobules; the blood-vessels form networks around and in the
lobules ; while the ducts which carry away the secretion (bile)
begin within the lobules in the form of tiny channels, running
between the cells.
The whole liver is invested in an envelope or capsule of con-
nective tissue (Glisson's capsule), and the lobules are divided
from one another by very delicate partitions of areolar tissue,
each lobule being about the size of a pin's head and filled with
the special liver cells.
The large portal vein and the small hepatic artery enter the
FIG. 103. — DIAGRAMMATIC REPRESENTATION OF Two HEPATIC LOBULES. The
left hand lobule is represented with the intralobular vein cut across; in the right
hand one the section takes the course of the intralobular vein, p, interlobular
branches of the portal vein; h, intralobular branches of the hepatic veins; s, sub-
lobular vein ; e, capillaries of the lobules. The arrows indicate the direction of the
course of the blood. The liver-cells are only represented in one part of each lobule.
liver together on its under surface at what is called the " gate
of the liver," the bile duct passing out at the same place. The
branches of these three vessels, enclosed by loose connective
tissue, in which are lymphatics and nerves, accompany one
another in their course through the organ. The smallest
branches penetrate between the lobules, and, surrounding and
lying between each lobule, are known as the interlobular
branches. From the interlobular branches of the portal vein,
thus surrounding the circumference of each lobule, run capillary
vessels, somewhat like the spokes of a wheel. These capillaries,
converging towards the centre, merge into a veinlet, the intra-
166
ANATOMY FOR, NURSES. [CHAP. XIV.
lobnlar vein, which, running down the middle of the lobule,
empties into a vein at its base. This vein, lying at the base of
each lobule, is called the sublobular vein, and empties its con-
tents into the hepatic veins, by means of which the blood is
conveyed from the back of the liver into the inferior vena cava.
FIG. 104. — LOBULE OF RABBIT'S LIVKR, VESSELS AND BILE DUCTS INJECTED.
a, central or intralobular vein ; b, b, interlobular veins; c, interlobular bile duct.
Thus each lobule is a mass of hepatic cells, pierced everywhere
with a network of blood capillaries.
The bile ducts commence between the hepatic cells in the
form of fine canaliculi lying1 between the adjacent sides of two
cells and forming a close network, the meshes of which corre-
spond in si'/.t; to the cells. At the circumference of the lobules,
CHAP. XIV.] ALIMENTATION.
these fine canaliculi pass into the interlobular bile ducts which,
running in connection with the blood-vessels, finally empty into
the two bile ducts which leave the liver at the opening, spoken
of above as the " gate of the liver."
The cells of the liver manufacture bile from the blood, and
discharge this into the minute bile canaliculi, whence it passes
into the bile ducts to be conveyed into the small intestine.
The cells, however, perform another important function, in that
they change some of the substances brought to them in the
blood from the digestive organs in such a manner as to render
these substances suitable for the nutrition of the body ; but, at
present it will be enough to consider the secretion of bile as
the only function of the liver.
The bile is taken from the liver by a right and left duct,
which soon unite to form the hepatic duct. The hepatic duct
runs downward and to the right for an inch and a half, and
then joins at an acute angle the duct from the gall-bladder,
termed the cystic duct. The hepatic and cystic ducts together
form the common bile duct (ductus communis choledochus),
which runs downwards for about three inches, and enters the
duodenum at the same opening as the pancreatic duct.
The gall-bladder (vide Fig. 102) is a pear-shaped sac, lodged
in a depression on the under surface of the right lobe of the
liver. It is lined by columnar epithelium, and its walls are
formed of fibrous and muscular tissue. It is held in position
by the peritoneum, and serves as a reservoir for the bile. Dur-
ing digestion the bile is poured steadily into the intestine ; in
the intervals it is stored in the gall-bladder.
To recapitulate : the digestive apparatus may be said to con-
sist of a tube and of important accessory organs placed in close
connection and communication with it. For convenience of
description, the tube may be divided in sections, each of which
is furnished with mechanical and chemical appliances for reduc-
ing the food into a soluble condition. First, the mouth cavity,
which is provided with muscular cheeks and movable jaw,
tongue, teeth, and the chemical solvent, saliva, secreted by the
salivary glands ; secondly, the two passages, the pharynx and
oesophagus, serving to convey the food into the next section,
the stomach, which is furnished with muscular walls for crush-
ing and churning the food, and with glands to secrete the acid
108 ANATOMY FOR NURSES. [CHAP. XIV.
digestive solvent, the gastric juice ; thirdly, the small intestine,
supplied with bile and pancreatic juice, and with a highly
specialized mucous membrane adapted to both digestive and
absorptive purposes; and lastly, the large intestine, having
feeble digestive properties, but serving to absorb all the nutri-
tious portion of the food still remaining, and to pass the residue
onwards to be finally thrown out of the body in the form of
feces.
CHAPTER XV.
ALIMENTATION CONCLUDED: DIGESTION; CHANGES THE FOOD
UNDERGOES IN THE MOUTH, STOMACH, SMALL AND LARGE
INTESTINE; SUMMARY OF DIGESTION; ABSORPTION.
Digestion. — Digestion is the process by means of which the
food we take into our mouths is transformed into a condition
of solution or emulsion suitable for absorption into the blood.
This transformation is rapid or gradual according to the nature
of the food-stuffs the digestive solvents are called upon to dis-
solve. We all know practically, for instance, that it takes much
longer to digest a piece of beefsteak than a cup of bouillon, and
that when we wish to save the digestive powers as much as pos-
sible we place a person upon " liquid diet."
Remembering that the three solid food-stuffs are proteids,
fats, and carbohydrates, we will proceed to describe how each
of these is transformed into a soluble condition in its course
through the alimentary canal.
Changes the food undergoes in the mouth ; mastication and
deglutition. — When solid food is taken into the mouth it is cut
and ground by the teeth, being pushed between them again and
again by the muscular contractions of the cheeks and the move-
ments of the tongue until the whole is thoroughly crushed and
ground down. During this process of mastication the salivary
glands are excited to very active secretion, the saliva is poured
in large quantities into the mouth, and mixing with the food
moistens it and reduces it to a soft pulpy condition. A certain
amount of air caught in the bubbles of the saliva also becomes
entangled in the food.
The food thus softened and moistened is collected from every
part of the mouth by the movements of the tongue, brought
together upon its upper surface, and then pressed backwards
169
170 ANATOMY FOE, NURSES. [CHAP. XV.
through the fauces into the pharynx. The elevation of the
soft palate prevents the entrance of food into the nasal cham-
bers, while the epiglottis bars its entrance into the air passages,
and it is guided safely and rapidly through the pharynx into the
oesophagus. Here it passes beyond the control of the will ; it
is grasped by the oesophageal muscles and by a continuous and
rapid peristaltic action is carried onwards and downwards into
the stomach.
Saliva. — Mixed saliva (spittle) as it appears in the mouth
is a glairy, frothy, cloudy fluid, the glairiness or ropiness being
due to mucus ; micro-organisms are also present in it to some
extent, and other foreign matters derived from the food.
Saliva is mainly water containing but little solid matter, its
specific gravity varying from 1002 to 1006. It depends for its
special action, as a digestive solvent, upon a ferment it contains
called ptyalin.1
The action of saliva upon the food. — The chief function of
saliva is to soften and moisten the food and to assist in mastica-
tion and deglutition. It has, however, a certain solvent action
upon food-stuffs, especially starch. Upon the fats and proteids
it has very little effect except to render them softer and better
prepared for the action of the other digestive juices.
By the ptyalin-ferment present in saliva, starch, which is an
insoluble substance, is changed into grape sugar, a highly solu-
ble and absorbable product. This change is best effected at the
temperature of the body, in a slightly alkaline solution, saliva
that is distinctly acid hindering or arresting the process. Boiled
starch is changed more rapidly and completely than raw, but
the food is never retained in the mouth long enough for the
saliva to more than begin the transformation of starchy matters.
After leaving the mouth, further conversion of starch into sugar
is arrested by the acid reaction of the gastric juice, and diges-
tion of this class of food-stuffs is practically suspended until
they again come in contact with the alkaline secretions in the
upper part of the small intestine.
1 Ferments are either organized or unorganized bodies ; of the former yeast
is a well-known example. The fermentative power of yeast which leads to the
conversion of sugar into alcohol is dependent upon the life of the yeast-cell.
When the yeast-cell dies, fermentation ceases. Ptyalin belongs to the latter
class ; it is an inorganic substance, not a living organism like yeast.
CHAP. XV.] ALIMENTATION. 171
During the processes of mastication, insalivation, and deglu-
tition, the food is first reduced to a soft pulpy condition ;
secondly, any starch it may contain begins to be changed into
sugar ; thirdly, it acquires a more or less alkaline reaction.1
Changes the food undergoes in the stomach. — The entrance of
food into the stomach acts as a stimulant to the whole organ.
The blood-vessels dilate, the glands pour out an abundant secre-
tion upon the mucous lining, and the different layers of the
muscular coat are excited to a continuous action. Delayed in
the stomach by the contraction of the pyloric ring-muscle, the
pulpy mass of food is carried round and round, and thoroughly
mixed with the gastric juice until it is dissolved into a thick,
grajdsh soup-like liquid, called chyme. The chyme thus formed
is from time to time ejected through the pylorus, accompanied
by morsels of solid, less well-digested matter. This ejection
may occur within a few minutes after the entrance of food into
the stomach, but does not usually begin until from one to two
hours after, and lasts from four to five, at the end of which
time the stomach is, after an ordinary meal, completely emptied.
Gastric juice. — Gastric juice, secreted by the small, tubular
glands in the mucous lining of the stomach, is a thin, colourless,
or pale yellow fluid, of an acid reaction. It contains few solids,
and is dependent for its specific action upon a ferment called
pepsin, which is only properly active in an acid solution ; and
we therefore find that free hydrochloric acid in the proportion
of 0.2 per cent is always present in normal gastric juice.
Action of gastric juice upon the food. — The gastric juice has
no action upon starch, and upon fats it has at most a limited
action ; that is, if adipose tissue be eaten, it will dissolve the
envelopes of the fat-cell and set the fat free, but it has no
power to emulsify them. The essential property of gastric
juice is the power it has of dissolving proteid matters and of
converting them into a substance called peptone. Whatever
the proteid may be, whether the albumin of eggs, the gluten of
flour in bread, the myosin in flesh, the result is the same, pepsin,
in conjunction with an acid at the temperature of the body,
transforms them into peptones.
Peptones readily dissolve in water, and pass with ease through
animal membranes. They are probably absorbed, as soon as
1 Weak alkalies stimulate the gastric glands to more abundant secretion.
172 ANATOMY FOR, NUESES. [CHAP. XV.
formed, by the blood-vessels in the walls of the stomach,
though some pass in the chyme through the pylorus into the
small intestine.
Changes the food undergoes in the small intestine. — The chyme
on entering the duodenum, after an ordinary meal, is a mixture
of various matters. It contains some undigested proteids ; some
undigested starch ; oils from fats eaten ; peptones formed in the
stomach, but not yet absorbed ; salines and sugar which have
also escaped complete absorption in the stomach ; all mixed with
a good deal of water and the secretions of the alimentary canal.
This acid mixture passing into the duodenum excites the secre-
tory action of the pancreas, and stimulates the bile to flow from
the gall-bladder; the glands of Lieberkiihn and Brunner also
become active, and all these secretions being alkaline, the acid
chyme is rapidly changed into an alkaline preparation, called
chyle.
Bile. — Bile, secreted in the lobules of the liver and stored in
the gall-bladder until needed, is a fluid of a bright golden red
colour, with an alkaline reaction. The chief solid constituents
of bile are the bile-salts and the colouring-matters or pigments.
Action of bile on food. — Upon proteids and starch, bile has
little or no digestive action. On fats, it has a slight solvent
action, and, in conjunction with pancreatic juice, has the power
to emulsify them. Bile possesses some antiseptic qualities.
Outside the body, its presence hinders putrefactive changes;
and when it is prevented from flowing into the alimentary
canal, the contents of the intestine undergo changes which do
not otherwise take place, and which lead to the appearance of
various products, especially of ill-smelling gases. Lastly, the
passage of fats through membranes is assisted by wetting the
membranes with bile or with a solution of bile-salts. It is
known that oil will pass to a certain extent through a filter-
paper, kept wet with a solution of bile-salts, whereas it will
not pass, or passes with extreme difficulty, through one kept
wet with distilled water.
Pancreatic juice. — Healthy pancreatic juice is a clear, some-
what viscid fluid, with a very decided alkaline reaction. It is
actively secreted by the pancreas during digestion and flows
into the intestine in conjunction with the bile. The Germans
call the pancreas the " abdominal salivary gland," though the
CHAP. XV.] ALIMENTATION. 173
pancreatic juice has a far more extensive action than the
saliva.
Among other important constituents the pancreatic juice con-
tains a ferment called trypsin, which, like pepsin, has the power
to transform proteids into peptones ; trypsin, however, requires
an alkaline medium to effect this transformation, while pepsin,
as we have already seen, requires the medium to be acid.
Action of pancreatic juice upon food. — On starch pancreatic
juice acts with great energy, rapidly converting it into sugar.
On proteids it practically exercises the same influence as the
gastric juice, for by it proteids are changed into peptones. On
fats it has a twofold action : it emulsifies them, and it splits
them up into fatty acids and glycerine. If we shake up olive
oil with water, the two cannot be got to mix: as soon as the
shaking ceases, the oil floats to the top; but if we shake up
olive oil with pancreatic juice, the oil remains evenly suspended
in it. The reason of this is, that the oil has been minutely
divided into tiny droplets, and each droplet surrounded by a
delicate envelope supplied from the albumin in the pancreatic
juice, so that they cannot fuse together to form the large drops,
which would soon float to the top. The pancreatic juice, in
thus emulsifying the fats, gives the white colour to the chyle,
which is its most striking external characteristic, the innumer-
able tiny oil-drops reflecting all the light that falls on its sur-
face. Secondly, the fats that are not emulsified, are broken up
into glycerine and fatty acids. The glycerine is absorbed, and
the fatty acids in the presence of an alkali form soaps which are
soluble in water and capable of absorption.
Thus pancreatic juice is remarkable for the power it has of
acting on all the food-stuffs, — starch, fats, and proteids.
Succus entericus, or intestinal juice. — Succus entericus is a
clear, yellowish fluid, having a faintly alkaline reaction and
containing a certain quantity of mucus. It is said to have a
solvent action upon all the food-stuffs, but at best its powers are
slow and feeble, and we have no satisfactory reasons for suppos-
ing that the actual digestion of food in the intestine is to any
great extent aided by it.
During the passage of the food through the small intestine
the remaining proteids, starch, and fats are converted into pep-
tones, sugar, and emulsified fats or soluble soaps, and these
174 ANATOMY FOR NUKSES. [CHAP. XV.
products as they are formed pass either into the lymphatics,
or into the blood-vessels in the intestinal walls, so that the
contents of the small intestine, by the time they reach the ileo-
csecal valve, are largely deprived of their nutritious constitu-
ents. So far as water is concerned, the secretion of water into
the small intestine maintains such a relation to the absorption
from it that the intestinal contents at the end of the ilium,
though otherwise mucja changed, are about as fluid as in the
duodenum.
Changes in the large intestine. — We have no very definite
knowledge of the particular changes which take place in the
large intestine. The contents become distinctly acid, although
the secretions of the intestinal wall are alkaline, and certain
acid fermentations must therefore take place in them. These
are probably due to the action of micro-organisms ; but however
this may be, the chief work of the colon is absorption. '
By the abstraction of all the soluble constituents, and espe-
cially by the withdrawal of water, the liquid contents become, as
they approach the rectum, changed into a firm and solid mass of
waste matters, ready for ejection from the body, and called feces.
The feces. — The feces consist of the undigested and indigesti-
ble substances of a meal : among them are the elastic fibres of
connective tissue ; the cellulose, which is the chief constituent
of the envelopes encasing the cells of plants ; the indigestible
mucin of mucus. These three materials, together with some
water, some undigested food-stuffs, and some excretory sub-
stances found in the various secretions poured into the aliment-
ary canal, form the bulk of the material expelled from the body.
To sum up the digestive processes : —
The transformation of the food we take into our mouths into
products capable of absorption, is mainly a chemical process.
The mechanical subdivision, bruising, and crushing of the food,
accomplished by the teeth and the muscular contractions of the
walls of the alimentary canal, is merely a process of preparation
for the solvent action of the digestive juices. Of these juices
there are five, each having a special action.
(1) The saliva, containing the digestive ferment ptyalin,
transforms starch into sugar.
(2) The gastric juice, containing pepsin (a ferment acting in
the presence of an acid), transforms proteids into peptones.
CHAP. XV.] ALIMENTATION. 175
(3) The pancreatic juice, containing trypsin (a ferment act-
ing in the presence of an alkali), transforms proteids into pep-
tones, and, by virtue of other constituents, transforms starch
into sugar, and emulsifies fats or turns them into soluble soaps.
(4) Bile, containing bile-salts and other matters, assists the
pancreatic juice in saponification and emulsion of fats, promotes
absorption of the same, and modifies putrefactive changes in the
intestine.
(5) Intestinal juice, containing mucus, transforms all food-
stuffs in a feeble fashion, not clearly demonstrated nor un-
derstood.
All material that these solvents fail to transform into a soluble
and absorbable condition is gradually worked downwards by the
peristaltic contractions of the alimentary canal, and finally
leaves the body as waste and useless matter.
NOTE. — For the sake of simplicity, we have considered digestion in a broad
way as the conversion of practically non-diffusible proteids and starch into more
diffusible peptones and highly diffusible sugar, and as the emulsifying of fats.
There is reason to believe that some of the sugar may be changed into lactic
acid, or even into butyric or other acids, and that some of the proteids are car-
ried beyond the peptone condition. But there is no doubt that the greater part
of the proteid is absorbed as peptone, that carbohydrates are mainly absorbed
as sugar, and that the greater part of the fat passes into the body as an
emulsion.
Absorption. — We have now to consider how the products of
digestion find their way out of the alimentary canal into the
tissues of the body; for, properly speaking, though the food may
be digested and ready for nutritive purposes, it is, until it
passes through the walls of the alimentary canal, still practi-
cally outside the body.
There are two paths by means of which the products of diges-
tion find their way into the blood : (1) by the capillaries in the
walls of the stomach and intestines ; and (2) by the lacteals in
the walls of the small intestine.
(1) The network of capillary blood-vessels is spread, as we
have seen (page 146), immediately beneath the basement mem-
brane of the mucous coat lining the interior of the alimentary
canal, and matters in solution pass readily by diffusion or
osmosis from the interior of the stomach and intestines into
the blood-vessels in their walls. All the blood from the diges-
176 ANATOMY FOE, NUKSES. [CHAP. XV.
tive organs is taken by the portal vein to the liver, and the
products of digestion are modified by the action of the liver
before they are returned to the general circulation by the
hepatic veins. The hepatic veins pour their contents into the
inferior vena cava, and the blood, enriched with the products of
digestion, finally finds its way into the right side of the heart,
whence it is taken to the lungs for purification before being
sent to all parts of the body.
During the passage of the blood through the liver, the liver-
cells not only take from it the material they need to form
the bile ; they also take from it material to form a starchy sub-
stance, called glycogen. This glycogen, stored in the liver-cells,
is gradually doled out, as it is needed, to the blood. It is not
doled out, however, in the form of glycogen, which closely
resembles starch, and is, therefore, insoluble, but in the form
of sugar or glucose. Thus the liver is a very complex organ
whose cells elaborate bile and glycogen, and by some fer-
ment-body, contained within themselves, convert the glycogen
into glucose.
(2) Matters in solution can pass into the blood-vessels, but
some other provision is necessary for the absorption of the
emulsified fats. We find, accordingly, in the villi, which so
closely cover the internal surface of the small intestine, little
rootlets or beginnings of lymphatic vessels, which are set apart
for the absorption of the fatty products of digestion.
These lymphatic rootlets or lacteals, as they are generally
called, occupy the centre of each villus. The emulsified fats
pass, probably aided by the bile, into the bodies of the columnar
cells on the surface of the villi, and from thence find their way
into the interior of the villus, and finally into the beginning of
the lacteal.1 The lacteals carry this fatty matter or chyle to
the larger lymphatics in the mesentery, and these empty their
contents into the thoracic duct which opens into the great veins
on the right side of the neck.
1 It is supposed that the fat gets into the interior of the lacteals mainly by
the action of the leucocytes or lymph corpuscles. First, the fat is taken up by
the epithelium cells on the surface of the villus, and, after passing through them,
is taken up by the leucocytes ; next, the leucocytes migrate, carrying the fat
particles by their amoeboid movements into the lacteal ; and finally, after enter-
ing the lacteal, they dissolve or break up and set the fat particles free.
CHAP. XV.] ALIMENTATION. 177
Thus the food in solution finds its way into the right side of
the heart after passing through the liver, and the emulsified
food after passing through the lymphatics. It is not to be
understood that matters in solution do not find their way into
the lacteals, nor, on occasion, emulsified fats into the blood-
vessels, but, broadly speaking, the food-products find their way
into the blood in the manner above described.
Final destination of food-stuffs. — It is impossible to say defi-
nitely what becomes of the different food-principles after they
have once entered the current of the blood. In general, it may
be said that the carbohydrates are used for the production of
force, and that the fats are stored in the body and used as fuel.
The proteids do all that can be done by the fats and carbo-
hydrates, and, in addition, form the basis of blood, muscles, and
all the connective tissues.
Still we cannot say that the carbohydrates perform a certain
work in the body and nothing else, or that the proteids and fats
do. It is, however, generally understood that the proteids, fats,
and carbohydrates each do an individual work of their own
better than either of the others can do it. They are also neces-
sary in due proportion to the nutrition of the body and work
together as well as in their separate functions.
The body has always a store of material laid by for future
use. If this were not the case, a person deprived of food would
die immediately, as he does when deprived of oxygen. The
great reserve forces of the body are stored in the form of adi-
pose tissue and glycogen. The glycogen is given out during
the intervals of eating to supply material for heat and energy ;
the adipose tissue is not so readily available, but may be called
upon during prolonged deprivation from food. For a certain
time the heat of the body may be maintained and work done on
these substances, although no food except water be taken.
In conclusion we may say the food in the blood supplies the
wants of the body in five different ways : —
"1. It is used to form all the tissues of the body.
" 2. It is used to repair the waste of all the tissues.
" 3. It is stored in the body for future use.
" 4. It is consumed as fuel to maintain the constant tempera-
ture which the body must always possess in a state of health.
" 5. It produces muscular and nervous energy." (Professor
Atwater.) N
CHAPTER XVI.
ELIMINATION; GENERAL DESCRIPTION OF THE URINARY OR-
GANS; STRUCTURE AND BLOOD-SUPPLY OF KIDNEY; SECRE-
. TION OF URINE; COMPOSITION AND GENERAL CHARACTERS
OF URINE.
IN the last four chapters we have seen that the blood is con-
stantly supplied by means of the respiratory and digestive
mechanisms, with all the chemical substances it requires to
maintain the life, growth, and activity of the body. These sub-
stances, entering the current of the blood, are carried to all the
tissues, and are incessantly combining with the chemical sub-
stances of which these tissues are composed. These combina-
tions are not left to chance ; each tissue has a special affinity
for the chemical substance in the blood which it requires for its
own growth and special form of activity ; the secretory cell of
the liver picks out substances from which it can manufacture
bile and glycogen ; the muscle fibre assimilates those that will
promote the changes upon which depends the power of con-
tractility. We know that the proteid compounds contain the
most essential elements for the formation of all kinds of tissue,
and that phosphate of lime is a necessary ingredient in the
hardening of bone, but we are utterly ignorant of how it comes
about that each tissue element is enabled to select the particular
material it needs and to reject that which it does not require.
Our bodies are masses of changing atoms, some of which, if
we may so express it, are on the " up grade," to construct the
various tissues, and some are on the " down grade," to form the
waste matters which are the final products of the tissues' activ-
ity. These changes, which are incessantly going on while life
lasts, are described under the general term of metabolism ; the
constructive changes being spoken of as anabolic, and the de-
structive as katabolic, changes. The final products then of
178
CHAP. XVI.] ELIMINATION. 179
the metabolism of the body will be certain waste matters, and
we shall now proceed to describe the mechanism of the organs
by means of which these wastes are removed from the body.
Elimination. — In passing through the blood and tissues of the
body, the proteids, fats, and carbohydrates are transformed into
urea (or some closely allied product), carbonic acid, and water,
the nitrogen of the urea being furnished by the proteids alone.
Many of the proteids contain sulphur, and also have phosphorus
attached to them in some combination, and some of the fats
taken as food contain phosphorus ; these elements are converted
by oxidation into phosphates and sulphates, and are excreted in,
that form in company with the other salts of the body.
Broadly speaking, then, the waste products are urea, carbonic
acid, salts, and water. These leave the body by one or other of
three main channels, the lungs, the skin, and the kidneys.
Some part, it is true, leaves the body by the bowels, for, as we
have seen, the feces contain, besides undigested portions of food,
substances which have been secreted into the bowels, and are
therefore waste products ; but the amount of these is very small
and, except in diseased conditions, of no special importance.
The waste matters discharged relatively by the lungs, skin,
and kidneys may be stated as follows : —
By the lungs : The greater part of the carbonic acid.
A considerable quantity of water.
By the skin : A variable but, on the whole, large quantity of
water.
A little carbonic acid.
A small quantity of salts.
By the kidneys : All, or nearly all, the urea and allied bodies.
The greater portion of the salts.
A large amount of water.
A very small quantity of carbonic acid.
We have already studied the mechanism by means of which
the lungs rid the blood of carbonic acid and water, and it now
remains for us to consider the mechanism of the skin and kid-
neys. In the present chapter we shall devote ourselves to the
consideration of the kidneys, which secrete the urine, and the
other urinary organs, the ureters, bladder, and urethra, which
collect the urine arid conduct it to the outside of the body.
180
ANATOMY FOB, NURSES. [CHAP. XVI.
Position and General Description of the Urinary Organs.
The kidneys. The kidneys are two compound tubular secret-
ing glands placed at the back of the abdominal cavity, one on
each side of the lumbar vertebrae. They are bean-shaped, with
the concave side turned towards the spine, and the convex side
directed outwards. Each kidney is about four inches long, two
broad, and one thick, and extends from the eleventh rib to nearly
the crest of the ilium, the
right being a little lower
than the left in conse-
quence of the large space
occupied by the liver.
They are covered by a
tough envelope of fibrous
tissue called the capsule
of the kidney, and are
usually embedded in a con-
siderable quantity of fat.
The ureters. — The ure-
ters are the excretory ducts
of the kidneys. They arise
in the middle of the con-
cave side, or hilus, of each
kidney and proceed ob-
liquely downwards and in-
wards through the lumbar
region of the abdomen into
the pelvis, to open ob-
FIG. 105. — THE RENAL ORGANS VIEWED ijmipiv KV two constricted
FROM BEHIND. R, right kidney; At aorta;
Ar, right renal artery ; Vc, inferior vena cava ; orifices into the base of the
Vr, right renal vein ; U, right ureter ; Vu, -, i i -, TT> -u „ ; , ~f
bladder; Ua, urethra. bladder. Each ureter is ot
the diameter of a goose.
quill, from sixteen to eighteen inches long, and consists of
muscular tissue lined by mucous membrane. The muscular coat
is arranged in two layers, an outer circular and an inner longi-
tudinal. Outside the muscular coat is a layer of fibrous con-
nective tissue carrying the blood-vessels and nerves with which
the tube is supplied.
The bladder. — The bladder is the reservoir of the urine. It
CHAP. XVI:] ELIMINATION. 181
is situated in the pelvic cavity behind the pubes, and is held in
position by ligaments. During infancy it is conical in shape
and projects above the upper border of the pubes into the hypo-
gastric region. In the adult, when quite empty it is placed
deeply in the pelvis ; when slightly distended, it has a round
form ; but when greatly distended, it is ovoid in shape and
rises to a considerable height in the abdominal cavity.
( Vide Plate VII.) When moderately distended, it measures
about five inches in length, and three inches across, and the
ordinary amount of urine which it contains is about one pint.
The bladder consists of plain muscular tissue lined by a strong
mucous membrane, and is covered partially by a serous coat
derived from the peritoneum. The muscular coat has three
layers, the principal fibres of which run longitudinally and cir-
cularly, the circular fibres being collected into a layer of some
thickness around the constricted portion or neck, where the
bladder becomes continuous with the urethra. These circular
fibres around the neck form a sphincter muscle which is nor-
mally in a state of contraction, only relaxing at intervals,
when the accumulation of urine within the bladder renders its
expulsion necessary.
The base of the bladder is directed downwards and back-
wards, and in the female lies in contact with the front wall of
the vagina and the lower part of the neck of the uterus. The
neck of the bladder is directed obliquely downwards and for-
wards.
The urethra. — The urethra is a narrow, membranous canal,
about an inch and a half in length in the female, and extending
from the neck of the bladder to the external orifice or meatus
urinarius. It is placed beneath the symphysis pubis, and is
embedded in the anterior wall of the vagina. Its direction
is obliquely downwards and forwards, its course being slightly
curved, the concavity directed forwards and upwards. It ad-
mits of considerable dilatation, its normal diameter, however,
being about a quarter of an inch. It is lined by a mucous coat,
which is continuous, externally, with that of the vulva, and,
internally, with that of the bladder. The external muscular
coat is also continuous with that of the bladder, but between
the mucous and muscular coats is a layer of thin, spongy tissue,
containing a network of large veins.
182
ANATOMY FOB, NUKSES. [CHAP. XVI.
The structure of the kidney. — The kidney is a secreting gland,
constructed upon the general plan of a compound secreting
gland, but possessing special features peculiar to itself. If we
cut a kidney in two lengthwise, it is seen that the upper end of
the ureter expands into a basin-like cavity, into which the solid
portion of the kidney projects in conical-shaped masses. This
dilated cavity of the ureter is called the pelvis or basin of the
kidney, and this pelvis is irregularly subdivided into smaller,
cup-like cavities, called calices,
which receive the pointed pro-
jections of the kidney substance.
The substance of the kidney
is readily seen by the naked eye
to consist of two distinct parts :
an outer, darker, and more
solid portion, called the cortex
(bark), and an inner, lighter
striated portion, called the me-
dulla (marrow), which is not a
solid mass, but more or less
distinctly divided into pyra-
midal - shaped sections. The
pointed projections or papillw
FIG. 106. -SECTION THROUGH THE Qf the pyramids are received
KIDNEY, SHOWING THE MEDULLARY AND L J
CORTICAL PORTIONS, AND THE BEGIN- by the irregularly disposed CUp-
NING OF THE URETER. (Henie.) Ct, like cavities of the pelvis. The
cortex ; M, medulla ; Py, papilla of pyra-
midal section, projecting into one of the bulk of the kidney Substance,
artery- °U ureter. *' ^^ **' ^ b°th ln the COI>teX and medulla'
is composed of little tubes or
tubules, closely packed together, having only just so much
connective tissue as is sufficient to carry a large supply of
blood-vessels and a certain number of lymphatics and nerves.
The different appearance of cortex and medulla is due to shape
and arrangement of tubules and blood-vessels.
Examined under the microscope, it is seen that the urinifer-
ous tubules begin as little rounded dilatations, called capsules,
in the cortex of the kidney. These capsules are joined to the
tubules by a constricted neck, and the tubules, after running a
very irregular course, open into straight collecting tubes, which
pour their contents through openings in the pointed ends or
CHAP. XVI.]
ELIMINATION.
183
papilla of the pyramids into the pelvis of the kidney. (Vide
Fig. 109.)
The tubules are composed of basement membrane, lined
throughout by epithelium
cells. The cells vary in
the different parts of a
tubule, some being more
especially adapted to secre-
tory purposes than others.
The blood-supply of the
kidney. — For its size, the
kidney is abundantly sup-
plied with blood. The
renal artery, coming di-
rectly from the aorta,
divides as it enters the
hilus of the kidney into
branches, which, slipping
around the pelvis, pass
inwards between the pyra-
mids. On reaching the
boundary line between the
cortex and the medulla,
the branches divide lat-
erally to form more or
less complete arches, (the
veins also divide in a
similar manner to form
venous arches). From the
arterial arches, vessels pass
upwards through the cor-
tex, giving off at intervals .
p . (Cadiat.) a, part of arterial arch; b, arterial
tiny arteries, each of which branch passing upwards through the cortex;
^ th (lilnrpfl pom- c, gloraerul us; <Z, efferent vessel; f, raeshwork
of capillaries; /, straight arterial vessels of
meilCement or capsule of medulla; g, venous arch; h, straight veins of
a uriniferous tubule. medulla-
These tiny arteries, entering the capsule, are spoken of as
afferent vessels. They push the thin walls of the capsule
before them, break up into a knot of capillary vessels, called a
glomerulus, and finally issue from the capsule as efferent ves-
FIG. 107. — VASCULAR SUPPLY OF KIDNEY.
184 ANATOMY FOR NUESES. [CHAP. XVI.
sels. These efferent vessels do not immediately join to form
veins, but break up into a close meshwork of capillaries around
the tubules, before they unite to form the larger vessels and
pour their contents into the veins forming the venous arches,
between the cortex and medulla. In this way the cortex of
the kidney is supplied with blood. The medulla also receives
its blood-supply mainly from the arterial arches. The blood
passes downwards in straight vessels between the uriniferous
tubules, to be returned by more or less straight veins to the
venous arches, whence it is conveyed by large branches into
the renal vein, which leaves the kidney at the hilus and pours
its contents into the inferior vena cava.
The renal artery in passing into the kidney is accompanied
by a network of nerves, called the renal
plexus. They are chiefly vaso-motor nerves,
and regulate the contraction and relaxation
of the renal blood-vessels.
Secretion of urine. — Urine is secreted
from the blood in two ways. It is partly
removed by a process of transudation or fil-
tration, and partly by the secretory action
of the cells lining the uriniferous tubules.
(1) Into the dilated extremity or capsule
of each tubule a small artery enters and,
pushing the wall of the capsule before
FIG. 108. — PLAN OF THE •. i ? . . i i «• i j -i
BLOOD VESSELS CONNECT- lt» Dreaks up into a bunch of looped capll-
ED WITH THE TUBULES. lanes. The blood in the loop of capillaries
or glomerulus is only separated from the
interior of the tubule by the thin walls of the capillaries and
the inverted wall of the capsule, which closely covers the
glomerulus. The artery entering the capsule is larger than
the issuing vein, and, during its passage through the glom-
erulus, the blood is subjected to considerable pressure. As a
result of this, a transudation of the watery constituents of the
blood, with some dissolved salts, takes place through the walls of
the blood-vessels and of the capsule into the tubule.
(2) After leaving the capsule, the efferent vein breaks up
into a meshwork of capillaries, which closely surrounds the
tubules, so that the blood is again brought into close communi-
cation with the interior of the tubules. The tubules are lined
CHAP, XVI.]
ELIMINATION.
185
with secreting cells, and these cells appear to have the power of
selecting from the blood the more solid waste matters (especially
the urea), which fail to filter through the flat cells forming the
wall of the capsule.
Thus the elimination of urine is a double process, being par-
tially accomplished by transuda-
tion, and partially by the selective
action of the secreting cells lining
the tubules.
Excretion of urine. — The uri-
niferous tubules commence in a
dilated extremity, the capsule, arid,
after a very devious course, termi-
nate in the collecting tubules,
which open on the pointed projec-
tions or papillae of the pyramids.
The fluid they contain passes into
the pelvis of the kidney, whence it
is carried along the ureters into
the bladder, partly by pressure and
gravity, and partly by the peri-
staltic contractions of the muscular
walls of the ureters. In the blad-
der the urine collects, its return
into the ureters being prevented by
the oblique entrance of these tubes
into the walls of the bladder.
Micturition is normally caused
by the accumulation of urine
within the bladder. The accu- r FlG" «».- DIAGRAM OF THE
COURSE OF TWO URINIFEROUS TUB-
mulation Stimulates the muscular ULES. M, malpighian capsule, or
walk tn onntrapt thp rpsktannp dilated extremity ; (7, convoluted por-
Ct> 1 J tion of tube ; H, loop, consisting of a
of the Sphincter at the neck of the descending and ascending limb; D,
bladder is overcome, and the urine c
is ejected through the urethra. Involuntary micturition may
occur as a result of spinal injury, involving the nerve centres
which send nerves to the bladder. It may be due to a want
of " tone " in the muscular walls, or it may result from some
abnormal irritation.
General characters of the urine. — Normal urine may be de-
180 ANATOMY FOR NURSES. [CHAP. XVI.
scribed as a transparent watery fluid, of a pale yellow colour,
acid reaction, specific gravity of 1020, and possessing an odour
which can only be described as " characteristic " or " urinous.':
Each one of these characters is liable to some variation within
the limits of health as well as in disease.
The transparency of urine may be diminished in health by the
presence of mucus, derived from the geni to-urinary tract, or by
the deposit of salts. In disease the urine may become clouded
by the presence of pus.
The colour of urine depends mainly upon the amount of water
it contains; also upon a diminution or increase of colouring
matters. In the copious urine of hysteria the colour is very
light, while in the diminished flow in fevers it is very high.
Abnormal colouring matters are derived from food or medicine,
or result from some diseased condition.
The reaction of urine should always be tested from a collec-
tion of urine passed during twenty-four hours, as it is affected
by diet and exercise. The reaction of mixed urine is normally
acid.
The specific gravity depends upon the amount of solid waste
matters present in the urine. In health, it may vary from 1015
to 1025. When the solids are dissolved in a large amount of
water, the specific gravity will naturally be lower than when,
from a deficiency of water, the urine is more concentrated. It
is notably heightened by the presence of sugar in the disease
called Diabetes Mellitus.
The composition of urine. — The chief constituents of normal
urine are water, urea, uric acid, colouring matters, and salts. Of
these constituents, urea is by far the most important, for it is
the chief solid waste product of the body. To eliminate urea is
the special work of the kidneys, and if for any reason they fail
to execute their work, the accumulation of urea in the system
leads to termination of life. Urea is the final product of all
proteid substances, and consequently a diet rich in proteids
will increase the amount of urea in the system. When the kid-
neys are disabled, it is customary for physicians to lighten their
work as far as possible by regulating the diet.
Of the salts, chloride of sodium occurs in the largest quan-
tity ; it sometimes disappears temporarily from the urine when,
in certain inflammatory diseases, it is needed by the blood.
CHAP. XVI.] ELIMINATION. 187
The chief abnormal constituents that are liable to appear in
the urine are albumin, giving rise to a condition called albu-
minuria, and sugar, giving rise to diabetes. The " casts," which
are found in urine in the various forms of Blight's disease, are
shed from the tubules in the shape of cylindrical moulds.
The quantity of urine passed in twenty-four hours. — The normal
quantity of urine passed in twenty-four hours is from forty to
fifty ounces, or about three pints. This will vary in health
with the condition of the skin, and the amount of fluid taken
into the body. The excretion of water by the kidneys is closely
related to that excreted by the skin. When the body is exposed
to cold, the blood-vessels in the skin are constricted, and the dis-
charge of water in the form of sweat is checked ; at the same
time the blood-vessels of the kidneys are dilated, there is a full
and rapid stream of blood through the glomeruli, and an in-
creased flow of urine results. On the other hand, when the
body is exposed to warmth, the cutaneous vessels are widely
dilated, and the skin perspires freely, while the renal vessels being
constricted, only a small and slow stream of blood trickles
through the glomeruli, and the urine which is secreted is
scanty. The effect on secretion, however, is more marked by
the amount of fluid absorbed through the alimentary canal ; an
increased secretion of water always follows an ordinary meal,
and when large quantities of water are drunk the amount of
urine is correspondingly increased.
The supra-renal capsules. — Lying immediately above each kid-
ney are two small flattened bodies of a yellowish colour. They
are usually classified with the ductless glands, as they have no
excretory duct. Each organ is invested by a fibrous capsule
which sends fibres into the glandular substance; these fibres
form a framework for the soft, pulpy substance of the gland,
and within the spaces of the framework are groups of cells.
The supra-renal capsules are plentifully supplied with blood-
vessels, nerves, and lymphatics, and they contain some striking
colouring matters. In disease of these organs, the skin fre-
quently becomes " bronzed," from an increase of pigment or
colouring matter. Their special normal functions are unknown.
188
ANATOMY FOR NURSES. [CHAP. XVI.
AMOUNT OF THE SEVERAL URINARY CONSTITUENTS
PASSED IN TWENTY-FOUR HOURS, EXPRESSED IN
GRAMMES AND GRAINS. (MARTIN.)
Urine in 24 hours.
1500 grammes.
23,250 grains.
In 1000 parts.
Water
1428.00
22,134.00
959 00
Solids
72.00
1 116 00
4800
The solids consist of —
Urea
33.00
511 50
2200
050
775
0 33
Hippuric acid
0.40
620
027
100
1550
0 fifi
Pigments and fats
10.00
15500
6 66
Sulphuric acid
200
31 00
1 33
Phosphoric acid
300
4fi 50
9 OO
7 00
108 50
A 7 A
Ammonia
075
10 no
0 50
Potassium '
2 50
qQ 7«
170
Sodium
noo
170 50
7 33
Calcium ....
A OK
q Q A
(\ -I a
Magnesium
0 20
q 00
013
71.60
1110.00
47.77
CHAPTER XVII.
ELIMINATION CONCLUDED: THE SKIN. NAILS AND HAIR.
BODILY HEAT: PRODUCTION OF HEAT; LOSS OF HEAT.
DISTRIBUTION OF HEAT; REGULATION OF HEAT.
HAVING described the mechanism by means of which the
lungs rid the body of carbonic acid and water, and of how the kid-
neys relieve it of urea, salts, and water, it now remains for us to
explain how the skin plays its part in elimination by yielding
up water, and a certain amount of carbonic acid and salts.
The skin. — The skin is not, like the kidneys, set apart to per-
- sw
M
FIG. 110. — SECTION OF EPIDERMIS. (Ranvier). H, horny layer, consisting of
s, superficial horny scales; sic, swollen-out horny cells; s.l. clear layer; M, Malpig-
hian layer, consisting of s.gr. granulur layer; p, many-sided or prickle cells; c,
columnar cells. Nerve fihrils may be traced passing up between the epithelium cells
of the Malpighian layer.
189
19o ANATOMY FOR NURSES. [CHAP. XVII.
form one special function. It is an important excretory organ,
but it Ls also an absorbing organ; it is likewise the principal
seat of the sense of touch, and serves, too, as a protective cover-
ing for the deeper tissues lying beneath it.
The skin, like a mucous membrane, consists of two distinct
layers; an epithelial covering, and a connective tissue basis.
The epithelium is a stratified epithelium and is called the epi-
dermis, or scarf -skin; the connective tissue layer is called the
derma, cutis vera (true skin), or corium. The epidermis is com-
posed of layers of cells, the deeper of which are soft and pro-
toplasmic, while the superficial layers are hard and horny.
Between the two layers is a fairly distinct line of granular-
looking cells, the granules in which have been thought to form
the horny matter in the superficial cells. In the coloured races
the single layer of elongated cells next the corium contains
pigment granules.
The growth of the epidermis takes place by the multiplication
of the cells in the deeper or Malpighian layer. As these cells
multiply by cell-division, they push upwards towards the surface
those previously formed. In their upward progress they
undergo a chemical transformation, and the soft protoplasmic
cells become converted into the flat, horny scales which are
constantly being rubbed off the surface of the skin.
The thickness of the epidermis varies in different parts of the
body, measuring in some places not more than 21^0 th of an inch,
and in others as much as ^th of an inch. It is thickest in the
palms of the hands and soles of the feet, where the skin is most
exposed to abrasion and pressure, but it forms a protective cover-
ing over every part of the true skin, upon which it is closely
moulded.
No blood-vessels pass into the epidermis ; it, however, receives
fine nerve-fibrils between the cells of the Malpighian layer.
The cutis vera or true skin is a highly sensitive and vascular
layer of connective tissue. It is, like the mucous membranes,
attached to the parts beneath it by a layer of areolar tissue, here
named "subcutaneous," which layer, with very few excep-
tions, contains fat. The connection in some parts is loose and
movable, as on the front of the neck ; in others, close and
firm, as on the palmar surface of the hand and the sole of the
foot.
CHAP. XVII.]
THE SKIN.
191
The cutis vera is often described as consisting of two layers,
a superficial or papillary layer, and a deeper or reticular layer.
The surface of the superficial or papillary layer is increased
by protrusions in the form of small conical elevations, called
papillae, and whence this layer derives its name. These papillae
contain for the most part looped blood-vessels, but they also con-
tain the terminations of medullated nerve-fibres in the shape of
little bodies, called tactile corpuscles.
The papillae seem chiefly to exist for the purpose of giving
the skin its sense of touch, being always well developed where
FIG. 111. — SECTION OF SKIN SHOWING Two PAPILLA: AND DEEPER LAYERS OF
EPIDERMIS. (Biesiadecki ) a, vascular papilla, with capillary loop passing from
subjacent vessel, c; h, nerve-papilla, containing tactile corpuscle, t; d, nerve passing
up to tactile body ; /,/, section of spirally winding nerve-tibres.
the sense of touch is exquisite. The papillae, containing tactile
bodies, are specially large and numerous on the palm of the
hand and the tips of the fingers, and on the corresponding
parts of the foot, while on the face and back they are small and
irregularly scattered.
The reticular layer of the corium is a continuation of the
papillary layer, there being no real division between them, and
is made up of bundles of white fibrous and elastic tissue which
gradually blends below with the subcutaneous areolar tissue. It
contains networks of blood-vessels, lymphatics, and nerves.
192 ANATOMY FOR NURSES. [CHAP. XVII.
The appendages of the skin are the nails, the hairs, the
sebaceous glands, and the sweat-glands. They are all devel-
oped as thickenings, or as down-growths, of the Malpighian
layer of the epidermis.
The nails. — The nails are composed of clear, horny cells of
the epidermis, joined together so as to form a solid, continuous
plate. Underneath each nail, the true skin is modified to form
what is called the bed or matrix of the nail. This bed is very
vascular, and is raised up into numerous papillse. At the
hinder part of the bed of the nail the skin forms a deep fold, in
which is lodged the root of the nail.
The growth of the nail is accomplished
by constant multiplication of the soft
cells in the Malpighian layer at the root.
These cells are transformed into dry, hard
scales, which unite into a solid plate, and
the nail, constantly receiving additions
from below, slides forward over its bed and
projects beyond the end of the finger.
When a nail is thrown off by suppuration,
or torn off by violence, a new one will grow
in its place, provided any of the cells of
the Malpighian layer are left.
The average rate of growth of the nails
FIG. 112.— PIECE OF is about 7V of an incn Per week.
HUMAN HAIR. (Highly _.. _ . ,-,, , . ,, »
magnified.) a, cuticle; The hairs. — The hairs are growths of
b, fibrous substance; c, the epidermis, developed in little pits, the
medulla. . ... . , .
hair-follicles, which extend downwards into
the deeper part of the true skin, or even into the subcu-
taneous tissue. The hair grows from the bottom of the little
pit or follicle, the part which lies within the follicle being
known as the root. The substance of the hair is composed
of coalesced horny cells, arranged in different layers, and we
usually distinguish three parts in the stem or shaft of hairs.
An outer layer of delicate, scale-like cells, the cuticle ; a middle,
horny, thick, and coloured portion, formed of elongated cells,
the fibrous substance; and a central pith formed of angular cells,
the medulla.
The root of the hair is enlarged at the bottom of the follicle
into a bulb or knob, and this bulb is composed of soft-growing
CHAP. XVII.] THE HAIES. 193
cells, and fits over a vascular papilla which projects into the
bottom of the follicle. The hair grows from the bottom of
the follicle by multiplication of the soft cells which cover the
papilla, these cells becoming elongated to form the fibres of the
fibrous portion, and otherwise modified to form the medulla and
cuticle. New hairs are produced indefinitely, so long as the
papillae and soft cells remain intact.
The follicles containing the hairs are narrow pits formed by
the involutions of the true skin and the epidermis. They slant
obliquely upwards, so that the
hairs they contain lie down on
the surface of the body. Con-
nected with each follicle are
small muscles of plain muscular
tissue which pass from the sur-
face of the true skin, on the side
to which the hair slopes, obliquely
downwards, to be attached to FlG- H3. — SECTION OF THE SKIN
, , - , „ , _ SHOWING THE HAIRS AND SEBACEOUS
the bottom Ot the lollicle. When GLANDS, a, the epidermis; 6, corium;
these muscles Contract, as thev C> muscles» attached to hair-follicles and
J to under surface of epidermis.
will under the influence of cold
or terror, the little hairs are pulled up straight, and stand " on
end " ; the follicle also is dragged upwards so as to cause a
prominence on the surface of the skin, whilst the cutis vera,
from which the little muscle arises, is correspondingly depressed:
in this way the roughened condition of the skin known as
" goose-skin " is produced. Hairs grow on an average at the
rate of half an inch per month. They are found all over the
body, except on the palms of the hands and the soles of the
feet, and on the last joints of the fingers and toes.
The sebaceous glands. — The sebaceous glands are small saccu-
lar glands, the ducts of which open into the hair-follicles. They
are lined with epithelium, and secrete a fatty, oily substance
(sebum) which they discharge into the hair-follicles. Several
sebaceous glands may open into the same follicle, and their size
is not regulated by the length of the hair. Thus, some of the
largest are found on the nostrils and other parts of the face,
where they often become enlarged with pent-up secretion. The
sebum lubricates the hairs and renders them glossy; it also
exudes, more or less, over the whole surface of the skin, and
194
ANATOMY FOB, NURSES. [CHAP. XVIL
keeps it soft and flexible. An accumulation of this sebaceous
matter upon the skin of the foetus furnishes the thick, cheesy r
oily substance, called the vernix caseosa.
The sudoriferous or sweat-glands, — All over the surface of the
skin are minute openings or pores. These pores are the open-
ings through which the sweat-glands pour their secretions upon
the surface of the body. The sweat-glands are tubular glands
with their blind ends coiled into little balls which are lodged
in the true skin or subcutaneous tissue ; from the ball the tube
is continued as the excretory duct of the gland up through
the true skin and epidermis, and finally opens on the surface
by a slightly widened orifice. Each tube is lined by a secreting
epithelium continuous
with the epidermis. The
coiled end is closely in-
vested by a mesh work of
capillaries, and the blood
in the capillaries is only
separated from the cav-
ity of the glandular tube
by the thin membranes
which form their respec-
tive walls. The secre-
tory apparatus in the
skin is somewhat simi-
FIG. 114. — COILED END OF A SWEAT-GLAND, lar to that which obtains
a, the coiled end ; b, the duct ; c, network of capil- in the kidnev ' in the
laries, inside which the sweat-gland lies. J '
one case the blood-
vessels are coiled up within the tube, while in the other the
tube is coiled up within the meshwork of blood-vessels.
The sweat-glands are abundant over the whole skin, but
they are most numerous on the palm of the hand and on the sole
of the foot; in the groin, and especially in the axilla, they are
larger than in other parts of the body. At a rough estimate,
the whole skin probably possesses from two to two and a half
millions of these glands, and their combined secreting power is
therefore very great.
Perspiration or sweat. — The sweat is a transparent colourless
fluid, of a distinctly salt taste and with a strong, distinctive odour.
When the secretion is scanty it has an acid reaction, but when
CHAP. XVIL] ELIMINATION CONCLUDED. 195
abundant it is alkaline. The chief normal constituents of sweat
are water, salts, fatty acids, and, some authorities state, a slight
amount of urea. In various forms of kidney disease urea may
be present in considerable quantity, the skin supplementing to
a certain extent the deficient work of the renal organs.
Quantity of perspiration. — Under ordinary circumstances, the
perspiration that we are continually throwing off evaporates
from the surface of the body without our becoming sensible of
it. This insensible perspiration, as it is called, usually amounts
to about twenty or thirty ounces in the course of twenty-four
hours. The amount, however, varies to a great extent — with
the condition of the atmosphere ; the amount of exercise taken ;
the quantity of fluid drunk ; the action of the kidneys. Varia-
tions also occur under the influence of mental emotions, the
action of drugs, or are induced by certain diseased conditions.
When more sweat is poured upon the surface of the body than
can be removed at once by evaporation, it appears on the skin
in the form of scattered drops, and we then speak of it as sen-
sible perspiration.
Less important functions of the skin. — Besides being an impor-
tant excretory organ, the skin is to a slight extent an absorbing
organ. In the sound, healthy skin, it is doubtful whether
matters in solution can be absorbed through the epidermic
covering, but if the horny layers of the epidermis be removed
by blistering, matters in solution readily pass into the blood-
vessels in the true skin. Oily substances, especially when well
rubbed in, are absorbed without removal of the epidermis.
Oxygen in small amount is also taken in through the skin,
but this gain to the body is counterbalanced by the carbonic
acid which is thrown off.
To sum up : the skin excretes a large amount of water and a
small amount of carbonic acid and salts; it absorbs a small
amount of oxygen and, under certain conditions, oily substances
and watery solutions ; it is a protective organ and a tactile
organ ; it supports two appendages, viz., the hair and nails, and
keeps itself flexible, and the hair glossy, by the secretion of
sebum.
There is still another function of the skin to be considered
before closing this chapter, and that is the part it plays in regu-
lating the temperature of the body.
196 ANATOMY FOE NUKSES. [CHAP. XVII.
Bodily heat. — In order that the bodily functions may be prop-
erly performed, it is necessary for the body to maintain a certain
temperature. Just as plants are killed by the frost, or withered
by the heat of the sun, so our tissues die if the bodily tempera-
ture falls below, or rises above, a certain limit. Our bodies,
however,, differ from plants in that they generate and regu-
late their own temperature, and possess the power of adapting
themselves to extremes of external heat and cold, without
necessarily suffering any vital injury. But, although the ex-
ternal temperature of the atmosphere may vary considerably
without hurting us, the bodily temperature must be kept at
an average standard of 98.6° F. (37° C.) if we are to remain in
a state of health. Slight variations are compatible with health,
the temperature being normally a trifle higher after eating or in
the evening of the day, but any variation over a degree above or
below 98.6° F. is indicative of danger.
Production of heat. — Heat in the body is produced by the
chemical changes that are constantly going on in the tissues.
Wherever metabolic changes are taking place, there heat is set free.
These changes take place more rapidly in some tissues than in
others, and in the same tissues at different times. The muscles
always manifest a far higher rate of activity than the connec-
tive tissues, and consequently the former evolve a larger pro-
portion of the bodily heat than the latter. We might liken the
different tissues of the body to so many fireplaces stored with
fuel, the fuel in some of the fireplaces being more easily ignited
and burning more rapidly than in others. The muscles and the
secreting glands, especially the liver, are supposed to be the
main sources of heat, as they are the seats of a very active
metabolism.
Loss of heat. — The heat thus continually produced is as con-
tinually leaving the body by the skin and the lungs, and by the
urine and feces. It has been calculated that in every 100 parts
about : —
88 per cent is lost by conduction and radiation from the surface of
the skin and the evaporation of the perspiration.
9 per cent is lost by warming the expired air and the evaporation
of the water of respiration.
3 per cent is lost by warming the urine and feces.
CHAP. XVII.] BODILY HEAT. 197
Distribution of heat. — The blood, as we know, permeates all
the tissues in a system of tubes or blood-vessels. Wherever
oxidation takes place and heat is generated, the temperature of
the blood circulating in these tissues is raised. Wherever, on
the other hand, the blood-vessels are exposed to evaporation,
as in the moist membranes in the lungs, or the more or less
moist skin, the temperature of the blood is lowered. The gain
and loss of heat balance one another with great nicety, and
the blood, circulating rapidly, now through warmer, and again
through cooler tubes, is kept at a uniform temperature of about
100° F. In this way the whole body is warmed in somewhat
the same way as we warm a house, the warm blood in the blood-
vessels heating the tissues, as the hot water in the hot-water
pipes heats the rooms in steam-heated dwellings.
Regulation of heat. — We have seen that active changes in
the body produce heat. The action of the muscles is a source
of heat, the activity of the glands during digestion, the active
changes taking place in the tissues during inflammation or
suppuration, or the changes caused by some specific micro-
organism, and we may say that there are normal and abnormal
sources of heat.
Normally, production of heat is balanced by loss of heat, and
the chief regulator of this gain and loss is undoubtedly the
skin. This is well seen in the case of muscular exercise.
Every muscular contraction gives rise to heat, and yet during
severe muscular exercise the temperature of the body does not
rise, or rises only to a trifling extent. This is accounted for
by the fact that when the muscular exertion causes the blood
to circulate more quickly than usual, the blood-vessels in the
skin dilate, the sweat-glands at the same time are excited to
pour out a more abundant secretion, and the heated blood pass-
ing in larger quantities through the cutaneous vessels (which
are kept well cooled by the evaporation of the perspiration),
the general average temperature of the body is maintained.
In pyrexia, or fever, rise of temperature is due to some cause
which, while increasing the metabolism of the tissues, at the
same time interferes with the process by means of which the
body rids itself of superfluous heat. We all know how hot and
dry the skin is liable to become in fevers ; how we try to restore
its function and lower the temperature by baths, sponging, and
198 ANATOMY FOR NUESES. [CHAP. XVII.
packs ; how we recognize the first signs of restored function —
the moist, warm sweat in the palm of the hand — as a pretty
sure sign that the fever is " broken." If a very high tempera-
ture persists for any length of time, the metabolism of the
tissues goes on at such a rapid rate that the capital of the body
is soon exhausted. Every organ works with feverish activity,
the heart and lungs increase their action, the pulse and respira-
tion become more and more hurried, and consequently more and
more feeble, until finally, unless relief is obtained, the patient
dies of exhaustion.
In exposure to variations of external temperature, the skin is
also the chief agent in regulating the heat of the body. Expos-
ure to cold causes the blood-vessels in the skin to contract, the
cold acting as a stimulus to the vaso-motor nerves, which con-
trol the calibre of the cutaneous blood-vessels. As a result,
less blood is sent to the surface to be cooled, and the average
blood-temperature is maintained. On the other hand, exposure
to warmth causes the cutaneous blood-vessels to dilate, and
more blood is sent to the surface to be cooled. Briefly, when
the external temperature is high, the cutaneous blood-vessels
dilate, and the sweat is also usually poured out upon the sur-
face of the skin ; when the external temperature is low, the cuta-
neous blood-vessels contract, and the skin usually remains dry.
By clothing we can aid the functions of the skin and the
maintenance of heat ; though, of course, clothes are not in them-
selves sources of heat. The object of clothing is, in winter, to
prevent conduction, radiation, and evaporation of heat from the
skin, and, in summer, to promote it. Of the materials used for
clothes, linen is a good conductor ; calico or muslin not quite so
good, while wool, silk, and fur are all bad conductors.
Subnormal temperature. — In some maladies the temperature
falls distinctly below the normal. This is no doubt chiefly due
to diminished metabolism. In cases of starvation, the fall of
temperature is very marked, especially during the last days of
life. The diminished activity of the tissues first affects the
central nervous system ; the patient becomes languid and
drowsy, and finally unconscious ; the heart beats more and
more feebly, the breath comes more and more slowly, and the
sleep of unconsciousness passes insensibly into the sleep of
death.
CHAPTER XVIII.
NERVOUS TISSUE.— THE CEREBRO-SPINAL SYSTEM: BRAIN AND
CRANIAL NERVES; SPINAL CORD AND SPINAL NERVES.—
SYMPATHETIC SYSTEM.
Nervous tissue. — Nervous tissue is the most highly organized
tissue of the body. It is pre-eminently the "master tissue,"
controlling, regulating, and directing all the other tissues.
Like muscular tissue, it is irritable and responds to stimuli;
but, unlike muscular tissue, it is not contractile.
If we stimulate a nerve-fibre, certain molecular changes are
started in the fibre, and these changes are transmitted along
the fibre without visibly altering its form. We call these
changes thus propagated along a fibre, "nervous impulses."
The stimuli that start these nervous impulses are varied and
numerous, and may originate from within the body as well as
from without. They usually originate from without; as, for
example, a ray of light falls on the nervous tissue of the eye,
the light stimulates and sets up changes in the nervous tis-
sue which are transmitted along the optic nerve to the brain.
These nervous impulses reaching the brain may start other
nervous impulses, which, travelling down certain nerves to
certain muscles, will cause those muscles to contract, in which
case we say a man starts. Again, sound falling on the ear, a
drop of water falling on the hand, some change in the air or
other surroundings of the body, or some change within the body
itself, may so affect the nervous tissue that nervous impulses
are started and travel to this point or that, giving rise to move-
ment as they reach muscular tissue, or producing some other
effect as they reach other tissues. We may say that nervous
tissue generates, transforms, and propagates nervous impulses.
When subjected to the microscope, nervous tissue is seen to
199
200
ANATOMY FOR NURSES. [CHAP. XVI1L
consist of two different structural elements, viz., fibres and
cells, both of which are enclosed and supported by a peculiarly
arranged connective tissue, and supplied with blood and lym-
phatic vessels. These fibres and cells are arranged in distinct
masses, called " nerve-centres," or in the form of cords, called
u nerves." The nervous cords are composed almost entirely of
the nerve-fibres, while the nerve-centres contain both fibres
and cells. The nerves con-
duct or propagate nervous
impulses, while the nerve-
centres generate, transmit,
and store them.
Nerve-cells. — Nerve-cells
vary much in size and
shape ; many are large,
some being amongst the
largest cells met with in
the body ; others, again, are
quite small. The nucleus
is generally large, clear,
and spherical, with a single
large and distinct nucleolus.
The cell substance is finely
granular, sometimes is in-
distinctly striated. All
nerve-cells have at least one
process or branch, — most
of them have more; and
they are often spoken of, in
consequence, as uni-polar,
bi-polar, and multi-polar
cells. In many nerve-cells
we recognize two distinct
kinds of processes : first,
those which, soon after
leaving the cell, divide and subdivide, until they become exceed-
ingly fine and delicate, and in some cases seem to join equally
processes from other cells; second, those which do not
FIG. 115. — MULTI-POLAR NERVE-CELL.
(Gerlach.) a, axis-cylinder, or nerve-fibre
process; b, pigment.
fine
divide and subdivide, but are prolonged as nerve-fibres.
Nerve-fibres. — These are of two kinds : those having a sheath
CHAP. XVIII.] THE NERVOUS TISSUE.
201
6 c d e /
FIG. 116. — NERVE-FIBRES.
3
a, nerve-
of white substance, and called medullated nerve-fibres ; and those
having no white sheath, called non-medullated nerve-fibres.
The medullated nerve-fibres consist of three parts: (1) the
axis-cylinder; (2) the white, or medullary sheath; (3) the
neurilemma, or enclosin-g sheath.
(1) The axis-cylinder is the essential part of every nerve-
fibre, and runs as a somewhat indistinct strand in the axis of
the fibre, and it is sometimes
called the axis-band. It ap-
pears to be in every case a
direct prolongation of a branch
of a nerve-cell, and may there-
fore be looked upon as a far-
extending cell -process. It
passes without any break or
interruption from the nerve- fibre> showing complete interruption of
Centres to the periphery; that the white substance; b, another nerve-
. . . £ fibre with nucleus. In both these nerve-
1S to Say, it IS continuous trom fibres the white substance is stained black
end to end, from its Origin to withosmic acid, and the axis-cylinder is
. seen running as an uninterrupted strand
Its termination. through the centre of fibre, c, ordinary
(2) The medullary sheath nerve-fibre unstained ; d, e, smaller nerve-
fibre ; /, varicose nerve-fibre ; g, non-me-
surrounding the axis-cylinder duiiated nerve-fibres.
is a fatt}r, semi-solid, white sub-
stance, which does not form a complete tube, but at tolerably
regular intervals is separated into segments ; it is not continu-
ous from end to end like the axis-cylinder, being wanting at
the origin and termination of the nerve-fibre. (We may look
upon the axis-cylinder as'the live or naked wire of the fibre, and
the white sheath as the isolating, non-conducting substance.)
(3) The neurilemma or enclosing sheath is a thin structure-
less tube, which tightly encloses the medullary sheath as the
sarcolemma encloses the muscle-fibre.
The non-medullated fibres have no medullary sheath and no
neurilemma. They frequently branch as the medullated fibres
never do except near their termination.
The nerve-fibres are gathered into cords of variable size to
form the nerves. These cords are called funiculi. Each f uni-
culus has its own sheath of connective tissue. If a nerve is
small, it may consist of one funiculus, but in larger nerves sev-
eral funiculi are united by connective tissue into one large cord
202
ANATOMY FOB NUKSES. [CHAP. XVIII.
or nerve, the whole nerve being covered by a dense fibrous
sheath of connective tissue.
Besides connecting the funiculi, the connective tissue serves
to convey the blood-vessels and lymphatics distributed to the
nerve-fibres.
The nerves that conduct nervous impulses towards the nerve-
centres are called afferent or sensory nerves, while those that
FIG. 117. — SECTION OF THE INTERNAL SAPHENOTJS NERVE. Stained in osmic
acid and subsequently hardened in alcohol. Drawn as seen under a very low magni-
fying power. (G. A. S.) ep, epineurium, or general sheath of the nerve, consisting
of connective tissue separated by cleft-like areolae, which appear as a network of
clear lines, with here and there fat-cells,/,/, and blood-vessels, v. ; per, perineurium,
or particular sheath of funiculus; end, endoneurium, or connective tissue within
f uniculus, embedded in which are seen the cut ends of the medullated nerve-fibres.
The fat-cells and the nerve-fibres are darkly stained by the osmic acid.
transmit nervous impulses from the nerve-centres towards the
periphery are termed efferent or motor nerves. Both afferent
and efferent fibres may run in the same sheath.
The nervous system. — The great nerve-centre of the body is
the cerebro-spinal centre or axis, consisting of the brain and
spinal cord. The nerves arising from this centre extend from
thence through the body to the muscles, sensible parts, and
CHAP. XVIIL] THE NERVOUS SYSTEM. 203
other organs, forming the mediums of communication between
these distant parts and the great nerve-centre.
Connected with the nerves in various situations are smaller
nerve-centres, called ganglia. A series of these ganglia, joined
together by nervous bands, form two large chains on either side
of the vertebral column,
extending from the base
of the cranium to the
coccyx. These ganglia,
with their nerves, are
generally called the sym-
pathetic system, and it is
usual to speak of the
nervous system as consist-
ing of the cerebro-spinal
system and of the sympa-
thetic system.
For convenience of de-
scription, we will divide
the cerebro-spinal system
into —
(1) Brain and cranial
nerves.
(2) Spinal cord and spi-
nal nerves.
Brain and cranial nerves.
-The brain, the most
complex and largest mass
of nervous tissue in the
body, is contained in the
complete bony cavity FlG. 118. _ DlAGRAM ILLUSTRATING~THE GEN-
formed by the bones of ERAL ARRANGEMENT OF THE CEREBRO-SPINAL
SYSTEM.
the cranium. It is cov-
ered by three membranes (also named meninges),— the dura
mater, pia mater, and arachnoid.
The dura mater, a dense membrane of fibrous connective
tissue, lines the bones of the skull, forming their internal perios-
teum, and covers the brain. It sends numerous prolongations
inwards for the support and protection of the different parts of
204
ANATOMY FOR, NURSES. [CHAP. XVIII.
the brain; it also forms sheaths for the nerves passing out of the
skull. It ma}' be called the protective membrane.
The pia mater is a delicate membrane of connective tissue,
containing an exceedingly abundant network of blood and
lymph vessels. It dips down into all the
crevices and depressions of the brain,
carrying the blood-vessels which go to
every part. It may be called the vascular
or nutritive membrane.
The arachnoid is a delicate membrane
which is placed outside the pia mater. It
passes over the various eminences arid de-
pressions on the surface of the brain, and
does not dip down into them like the pia
mater. Beneath it, between it and the
pia mater, is space (sub-arachnoid space)
in which is a certain amount of fluid. The
sub-arachnoid space at the base of the brain
is of considerable size, and contains a large
amount of this clear limpid fluid, called the
cerebro-spinal fluid. This fluid probably
acts as a sort of protective water-cushion to
the delicate nervous structure, and pre-
vents the effects of concussions communi-
cated from without.
The brain is a semi-soft mass of white
and gray matter. The white matter con-
sists of very small, medullated nerve-fibres,
running in various directions, and sup-
ported by a delicate connective tissue
FIG. 119.— SIDE VIEW framework. The gray matter consists of
OF THE BRAIN AND SPI- ceus an(j fine Rray fibres, also supported
NAL CORD IN PLACE. The .
parts which cover the cere- by Connective tissue.
bro-spinal centre are re- The bmin ig divided into four principal
moved. * -1-
parts: the cerebrum, the cerebellum, the
pons Varolii, and the medulla oblongata.
The medulla oblongata is a continuation of the spinal cord,
which, on passing into the cranial cavity through the foramen
magnum, widens into an oblong-shaped mass. It is directed
backwards and downwards, its anterior surface resting on a
CHAP. XVIII.] THE NEKVOUS SYSTEM. 205
groove in the occipital bone, and its posterior surface forming
the floor of a cavity between the two halves or hemispheres of
the cerebellum. The cavity, called the fourth ventricle, is an
expanded continuation of a tiny central canal which runs
throughout the whole length of the spinal cord.
The cerebellum, or little brain, overhangs the fourth ventricle.
It is of a flattened oblong shape, and measures from three and a
half inches to four inches transversely, arid from two to two and
a half inches from before backwards. It is divided in the middle
FIG. 120. — THE BASE OF THE BRAIN. 1, longitudinal fissure; 2, 2, anterior lobes
of cerebrum ; 3, olfactory bulb ; 7, optic commissure; 9, 3rd nerve ; 11, 4tb nerve ;
13, 5tb nerve ; 14, crura cerebri ; 15, Oth nerve ; 16, pons Varolii ; 17, 7th nerve ; 19,
8th nerve; 20, medulla oblongata ; 21, 9th nerve; 23, 10th nerve; 25, llth nerve;
27, 12th nerve; 28, 2i), 30, 31, 32, cerebellum.
line into two halves or hemispheres by a central depression,
each half being subdivided by fissures into smaller portions or
lobes. The surface of the cerebellum is traversed by numerous
curves or furrows, which vary in depth. In the medulla ob-
longata, the gray matter is placed in the interior, and the white
on the exterior; in the cerebellum, the gray is on the outside,
and the white within.
The pons Varolii, or bridge of Varolius, lies in front of the
medulla oblongata. It consists of alternate layers of transverse
206 ANATOMY FOB, NURSES. [CHAP. XVIII.
and longitudinal white fibres, intermixed with gray matter.
The transverse fibres come mainly from the cerebellum, and
serve to join its two halves. The longitudinal fibres come from
the medulla oblongata. This bridge is a bond of union between
the cerebrum, cerebellum, and medulla oblongata.
The cerebrum is by far. the largest part of the brain. It is
egg-shaped or ovoidal, and fills the whole of the upper portion
of the skull. It is almost completely divided by the median
fissure into two hemispheres, the two halves, however, being
connected in the centre by a broad transverse band of white
fibres, called the corpus callosum. Each half is subdivided into
lobes.
The longitudinal fibres of the medulla oblongata, passing
through the pons Varolii, become visible in front of the bridge
as two broad, diverging bundles. These two bundles form what
are called the crura cerebri^ or pillars of the brain, and are situ-
ated on the under surface of each hemisphere. Between the
crura cerebri is a narrow passage (aqueduct of Sylvius) lead-
ing from the fourth ventricle into a smaller cavity called the
third ventricle. In each side wall of the third ventricle is an
opening (foramen of Monro) which leads into two large cavi-
ties, the lateral ventricles, and which occupy the centre of each
half of the cerebrum. (It will be seen from the above descrip-
tion that the cavities in the centre of the brain are continuous
with the central canal in the spinal cord, and also that fibres
from the cord pass into the centre of the cerebrum.) Forming
the floors of the ventricles, lodged in the crura cerebri, and
scattered in their neighbourhood, are irregularly shaped masses
of gray matter, intricately connected with one another and with
the gray matter in the medulla oblongata. The surface of the
cerebral hemispheres is folded, the folds or convolutions being
deeper and more numerous in some brains than others: the
whole of the convoluted surface is composed of gray matter
arranged in several layers of cells and fibres.
The whole brain appears to consist of a number of isolated
masses of gray matter — some large, some small — connected
together by a multitude of fibres of white matter arranged in
perplexing intimacy. But a general arrangement may be recog-
nized. The numerous masses of gray matter in the interior of
the brain may be looked upon as forming a more or less contin-
CHAP. XVIII.] THE NERVOUS SYSTEM. 207
uous column, arid as forming the core of the central nervous
system, while around it are built up the great mass of the cere-
brum and the smaller mass of the cerebellum. This central
core is connected by various ties with the spinal cord, besides
being, as it were, a continuation of the gray matter in the
centre of the cord. It is also connected at its upper end, by
numberless fibres, to the gray matter on the surface of the cere-
brum.
The different masses of gray matter being so closely asso-
ciated and connected with one another, it will be seen that it
becomes a very difficult matter to assign definite functions to
definite areas. Of late years, however, a great deal has been
accomplished in this direction, and it has become possible to
locate the centres that preside over the organs of speech, sight,
hearing, etc., and over the movement of muscles in any part
of the body. Owing to the crossing or decussation of fibres in
the medulla oblongata, injuries to nerve-centres on the right
side of the brain will affect the left side of the body, below the
decussation.
The average weight of the brain in the male is 49|- oz. ; in
the female, 44 oz. It appears that the weight of the brain in-
creases rapidly up to the seventh year, more slowly to between
sixteen and twenty, and still more slowly to between thirty and
forty, when it reaches its maximum. Beyond this age the brain
diminishes slowly in weight, about an ounce every ten years.
The size of the brain bears a general relation to the capacity of
the individual. Cuvier's brain weighed rather more than 64 oz.,
while the brain of an idiot seldom weighs more than 23 oz. The
number and depth of the cerebral convolutions also bear a close
relation to intellectual power ; babies and idiots have few and
shallow folds, while the brains of men of intellect are always
markedly convoluted.
The cranial nerves. — The cranial nerves, twelve in number on
each side, arise from the base of the brain and medulla oblon-
gata (iride Fig. 120), and pass out through openings in the base
of the skull. They are named numerically according to the
order in which they pass out of the skull. Other names are also
given to them derived from the parts to which they are dis-
tributed, or from their functions. Taken in their order from
before backwards, they are as follows : —
208 ANATOMY FOR NURSES. [CHAP. XVIII.
1. Olfactory. 7. Facial.
2. Otpic. 8. Auditory.
3. Motor oculi. 9. Glosso-pharyngeal.
4. Pathetic. 10. Pneumo-gastric.
5. Trifacial. 11. Spinal-accessory.
6. Abducens. 12. Hypo-glossal.
The first or olfactory nerve is the special nerve of the sense
of smell. It arises by three roots from the interior of the brain,
and sends numerous fibres through the perforated plate of the
ethmoid bone, to be distributed to the mucous membrane lining
the nasal chamber.
The second or optic nerve is the special nerve of the sense of
sight. It enters the orbit and is distributed to the interior of
the eyeball. Before entering the orbit the nerve is connected
with its fellow of the opposite side by a band or commissure,
and from this union it may be traced back along the optic tract
to its deep origin in the central gray matter of the brain.
The third or motor oculi nerve is the chief mover of the eye ;
it supplies all the muscles of the eye with the exception of the
superior oblique and external rectus. Its origin may be traced
back to the gray matter in the medulla oblongata.
The fourth or pathetic nerve, the smallest of the cranial
nerves, supplies the superior oblique muscle of the eye. It
arises close to the third nerve.
The fifth or trifacial nerve is the largest of the cranial nerves.
It arises by two roots, — a posterior or sensory, and an anterior
or motor. The posterior root is larger than the anterior, and
has a ganglion developed on it. The fibres from the two roots
coalesce into one trunk, and then subdivide into three large
branches: the ophthalmic, the superior maxillary, and the
inferior maxillary. The ophthalmic branch is the smallest, and
is a sensory nerve. It supplies the eyeball, the lachrymal gland,
the mucous lining of the eye and nose, and the skin and mus-
cles of the eyebrow, forehead, and nose. The superior maxil-
lary, the second division of the fifth, is also a sensory nerve and
supplies the skin of the temple and cheek, the upper teeth, and
the mucous lining of the mouth and pharynx. The inferior
maxillary is the largest of the three divisions of the fifth, and is
both a sensory and motor nerve. It sends branches to the tem-
ple and the external ear; to the teeth and lower jaw; to the
CHAP. XVIII.] THE NERVOUS SYSTEM. 209
muscles of mastication : it also supplies the tongue with a
special nerve (the lingual) of the sense of taste.
The sixth or abducens nerve supplies the external rectus
muscle of the eye.
The seventh or facial nerve is the motor nerve of all the
muscles of expression in the face : it also supplies some muscles
of the neck and ear. It arises close to the sixth nerve on the
floor of the fourth ventricle.
The eighth or auditory nerve is the special nerve of the sense
of hearing, being distributed exclusively to the internal ear.
The ninth or glosso-pharyngeal nerve is distributed, as its
name indicates, to the tongue and pharynx, being the nerve of
sensation to the mucous membrane of the pharynx, of motion
to the pharyngeal muscles, and the special nerve of taste to part
of the tongue.
The tenth or pneumogastric nerve has a more extensive dis-
tribution than any of the other cranial nerves, passing through
the neck and thorax to the upper part of the abdomen. It
contains both motor and sensory fibres. It supplies the organs
of voice and respiration with motor and sensitive filaments;
and the pharynx, oasophagus, stomach, and heart with motor
fibres. This nerve is sometimes spoken of as the par vagus.
The eleventh or spinal-accessory nerve consists of two parts :
one, the spinal portion, and the other, the accessory portion to
the tenth nerve. It is a motor nerve supplying certain muscles
of the neck. It differs from the other cranial nerves in arising
from the spinal cord, but it leaves the skull by the same aper-
ture as the pneumogastric and glosso-pharyngeal.
The twelfth or hypoglossal nerve is the motor nerve of the
tongue.
All the cranial nerves, with the exception of the two first
pairs and the spinal accessory, arise from the gray matter in the
medulla oblongata, and any injury to the medulla oblongata is
attended with the most serious results, while extensive injury
arrests the respiratory processes and causes instant death.
It will be observed that of the twelve pairs of cranial nerves,
four, arid a part of a fifth, are distributed to the eye ; viz. the optic,
motor oculi, pathetic, abducens, and the ophthalmic branch of
the fifth. The ear has one special nerve, the auditory, and is
sparingly supplied with motor and sensitive fibres from other
210 ANATOMY FOE NUKSES. [CHAP. XVIII.
nerves. The nose has also one special nerve, the olfactory, and
is more abundantly supplied than the ear, with motor and sen-
sitive fibres from other nerves. The tongue has two special
branch nerves of taste, — the lingual, a branch of the fifth, and
the glossal, a branch of the ninth: it has also its own motor
nerve, the hypoglossal.
The spinal cord and spinal nerves. — The spinal cord is a
column of gray and white soft substance, extending from the
top of the spinal canal, where it is continuous with the brain, to
about the second lumbar vertebra, where it tapers off into a fine
thread. Before its termination it gives off a number of fibres
which form a tail-like expansion, called the cauda equina.
Like the brain, the spinal cord is protected and nourished by
three membranes. These membranes have the same names and
practically exercise the same functions as those enveloping the
brain. The dura mater is not attached to the walls of the spinal
canal, being separated from them by a certain quantity of areo-
lar and adipose tissue and a network of veins. Therefore, the
spinal cord does not fit closely into the spinal canal, as the
brain does in the cranial cavity, but is, as it were, suspended
within it. It diminishes slightly in size from above downwards,
with the exception of presenting two enlargements in the
cervical and dorsal regions. It is usually from sixteen to
seventeen inches long, and has an average diameter of three-
fourths of an inch. The spinal cord is almost completely
divided into lateral halves by an anterior and posterior fissure,
the anterior fissure dividing it in the middle line in front, and
the posterior fissure, in the middle line behind. In conse-
quence of the presence of these fissures, only a narrow bridge
of the substance of the cord connects its two halves, and this
bridge is traversed throughout its entire length by a minute cen-
tral canal, — the canalis centralis. On making a transverse sec-
tion of the spinal cord, the gray matter is seen to be arranged in
each half in the form of a half-moon or crescent, with one end
bigger than the other, and with the concave side turned out-
wards. The convex sides of the gray matter in each half
approach one another, and are joined by the isthmus or bridge
which contains the central canal. The tips of each crescent
are called its horns or cornua, the front or anterior cornua
being thicker and larger than the posterior. The white mat-
CHAP. XVIII.] THE NERVOUS SYSTEM.
211
ter of the cord is arranged around and between the gray matter,
the proportion of gray and white matter varying in different
regions of the cord. The white matter, as in the brain, is com-
posed of medullated nerves, and the gray matter of nerve-cells
FIG. 121. — TRANSVERSE SECTIONS OF THE SPINAL CORD AT DIFFERENT LEVELS.
(Gowers.) (Twice the natural size.) The letters and numbers indicate the position of
each section : Ca, at level of coccygeal nerve ; Sac4, of 4th sacral ; Is, at third lum-
bar, and so on. The gray substance is shaded dark, and the nerve-cells within it are
indicated by dots.
and fine gray fibres, all held together and supported by delicate
connective tissue. The majority of the nerves run in a longi-
tudinal direction.
There is no real division between the brain and spinal cord,
212
ANATOMY FOR NURSES. [CHAP. XVIII.
the brain being built upon the cord, and together they form the
great nerve-centre or axis — the cerebro-spinal — which, by means
of the cranial and spinal nerves, is placed in
connection with all parts of the body. Al-
though the gray matter in the spinal cord
is intimately connected with the gray matter
in the brain, it has some functions indepen-
dent of the brain, which will be described in
connection with the spinal nerves.
The spinal nerves. — There are thirty-one
pairs of spinal nerves, arranged in the follow-
ing groups, and named from the regions
through which they pass. They are : —
Cervical 8 pairs
Dorsal 12 "
Lumbar 5 "
Sacral 5 "
Coccygeal 1 pair
The spinal nerves pass out of the spinal
canal through the intervertebral foramina,
the openings between the vertebree spoken
of in the lesson on the bones of the spine.
Each spinal nerve has two roots, an anterior
root and a posterior root. The fibres con-
nected with these two roots are collected into
one bundle, and form one nerve just before
leaving the canal through the intervertebral
openings. Before joining to form a common
trunk, the fibres connected with the posterior
root present an enlargement, this enlargement
being due to a ganglion, or small nerve
centre. The fibres of the anterior root arise
nal cervical nerves; from tfo gray matter [n the anterior COH1U,
FIG. 122.— BASE OF
BRAIN, SPINAL CORD,
AND SPINAL NERVES.
V, IX, cranial nerves;
a, 6, c, d, sympathetic
ganglia; C'M, spi-
Di-12, spinal dorsal
nerves; Z,*-5, spinal
lumbar nerves ; S M
sacral ; 6, coccygeal.
and appear for the most part to be direct pro-
longations from the nerve-cells there. The
fibres of the posterior root, on the other
hand, appear to arise in most cases from the cells in the ganglion,
and to grow into the nerve-centres forming the gray matter in the
posterior cornu. The fibres growing from the anterior root are
CHAP. XVIII.] THE NERVOUS SYSTEM.
213
efferent fibres, and convey nervous impulses from the spinal
cord to the periphery. The fibres growing into the posterior
root are afferent fibres, and convey nervous impulses from the
periphery to the spinal cord. The afferent fibres usually con-
vey sensory impressions, and the efferent motor impulses.
The thirty-one pairs of spinal nerves, containing within the
one sheath both afferent and efferent fibres, issue at regular
intervals from the spinal canal, and are distributed to all parts
of the body, the
efferent or motor
fibres being distrib-
uted to the muscular
tissue, and causing
contraction of the
muscles ; the afferent
or sensory fibres end-
ing commonly in the
skin, and conveying
nervous impulses to
the nerve - centres
which give rise to
sensation.
The nervous im-
pulses transmitted by
the afferent nerves to
the spinal cord are
the cord to the brain,
and the nervous im-
FIG. 123. — SECTIONS OF SPINAL CORD AND
NERVE-ROOTS. A, anterior view; B, side view; C,
USUallv forwarded bv transverse section; J), two isolated roots of a spinal
J * nerve. 1, anterior fissure; 2, posterior fissure; 3,
groove formed by anterior roots; 4, groove formed
by posterior roots ; 5, fibres of anterior root ; 6,
fibres of posterior root; 6, ganglion on posterior
pulses sent out along root,
the efferent fibres to
the muscles are also commonly transmitted by the spinal cord
from the brain. And if the spinal cord be so injured as to
practically sever its connection with the brain, it will be found
that paralysis and insensibility of the body below the injury
will ensue, showing conclusively that, severed from the brain,
the ability of the spinal cord to give rise to sensation, or to
control muscular contractions, is seriously impaired. Yet the
gray matter in the spinal cord has a certain power of its own,
for after the cord has been severed from the brain, spasmodic
214
ANATOMY FOR NURSES. [CHAP. XVIII.
contraction of muscles can be made to take place. The appli-
cation of stimuli to the afferent nerve-fibres ending in a portion
of the skin will set up
changes in the fibres,
which changes will be
transmitted by them to
the gray matter in the
posterior root of the
spinal cord. These
changes or nervous im-
pulses, instead of being
sent up the cord to the
seat of sensation in
the brain, and thus
giving rise to sensa-
tion, are transmitted
to the gray matter in
the anterior root of
the cord, and conveyed
thence by the efferent
fibres to the muscles,
which they cause to
contract. This power
of transforming an af-
ferent into an efferent
impulse is termed the
reflex power of the
spinal cord.
The sympathetic sys-
tem.— The sympathetic
system consists of a
double chain of gan-
glia, placed on each
side of the spinal
column, and united
with each other by
Fio. 124. — GENERAL VIEW OF THE SYMPATHETIC longitudinal filaments.
SYSTEM. 1, 2, 3, cervical ganglia; 4, 1st thoracic T, ,, . f,
ganglion; 5, 1st lumbar ganglion; 6, 7, sacral gang- ln6
lion: <», 9, cardiac nerves; 13, branch of pneumo- Ha are Smaller than
gastric nerve ending in semi-lunar ganglion- 14 ,1 • ,1 i • j
epi-astric plexus. ' those in the brain and
CHAP. XVIII.] THE NERVOUS SYSTEM.
215
spinal cord, and the fibres 'that arise from them are mostly of
the non-medullated variety.
These ganglia and nerves do not form an independent ner-
vous system, for each ganglion is connected by motor and sensi-
tive fibres with the cerebral system. The sympathetic nerves are
distributed to the viscera and blood-vessels, of which the move-
ments are involuntary, and the general sensibility obtuse. They
form networks or plexuses upon the heart, about the stomach,
and other viscera in the trunk ; they also enter the cranium,
send branches to the organs of special sense, and, in particu-
lar, influence the pupil of the eye. Their most important
distribution, however, is in connection with the blood-vessels.
They form plexuses around the vessels,
especially the arteries, and send fibres
to terminate in the involuntary mus-
cular tissue of which the walls of
these tubes are largely composed. The
nerves thus distributed are called
" vaso-motor " nerves.
The unity of the nervous system. —
From the foregoing description of the
nervous system, it is clear that it forms
one continuous whole, through the
agency of which all the varied activi- FlG- 125- — NERVE ENDING
,, . . , .. IN MUSCULAR FIBRE OF A
ties ol the body are controlled and LIZARD. (Kuhne.) The end-
regulated. We may compare it to a plate, or motorial ending of the
' axis-cylinder, is seen sideways.
telegraphic system, the central office
of which would represent the brain and spinal cord, the more
important sub-offices the sympathetic ganglia, and the minor
offices the isolated ganglia ; while the telegraph wires, directly
or indirectly uniting all, would correspond to the nerves. And
just as a message started along some outlying wire may be
transmitted to a central office, and, according to the informa-
tion received, will be stopped there, or sent to some other
centres to be forwarded by them in one direction, in two direc-
tions, or all over the country, — so may a nervous impulse reach-
ing the brain merely excite some change in the brain itself, or
be sent out from thence along the nerve-trunks to excite activi-
ties in various parts of the body.
Peripheral termination of nerves. — The nerves have their origin
216 ANATOMY FOE, NUKSES. [CHAP. XVIII.
in the gray matter of the brain, in the spinal cord, and in vari-
ous ganglia ; their termination, or peripheral distribution, is not
so easy to determine.
All nerves, medullated or non-medullated alike, in approaching
their final distribution, divide ; that is, the numerous strands or
fibres which go to make up a nerve separate from one another.
If we follow a fibre, we find, if it is a medullated one, that the
FIG. 126. — SECTION OF SKIN SHOWING TACTILE CORPUSCLE IN PAPILLA, d,
nerve passing up to tactile corpuscle ; t, tactile corpuscle.
sheaths enclosing it gradually disappear, and finally the axis
cylinder itself splits into its component fibrils. These fibrils
may terminate in invisible threads, as between the cells in the
Malpighian layer of epidermis, or they may terminate in special
end organs, such as the tactile bodies in the papillae of the
skin, the round-end bulbs in the conjunctiva, the motorial rami-
fications in the muscular fibres, and in other ways too numerous
and too complicated for us to attempt to describe.
Degeneration and regeneration of nerves- — The divided ends of a
nerve that has been cut across readily reunite by cicatricial tissue, — that is
to say, the connective tissue framework unites, — but the cut ends of the
fibres themselves do not unite. On the contrary, the peripheral or severed
portion of the nerve begins to degenerate, the medullary sheath breaks up
into a mass of fatty molecules and is gradually absorbed, and finally the
CHAP. XVIII.] THE NERVOUS SYSTEM.
217
axis-cylinder also disappears. In regeneration, the new fibres grow afresh
from the axis-cylinders of the central end of the severed nerve-trunk, and,
penetrating into the peripheral end of the trunk, grow along this as the
axis-cylinders of the new nerve, each axis-cylinder becoming after a time
FIG. 127.— -END-BULBS FROM THE HUMAN CONJUNCTIVA. (Longworth.) A,
ramification of nerve-fibres in the mucous membrane, and their termination in end-
bulbs, as seen with a lens ; B, an end-bulb more highly magnified ; a, nucleated cap-
sule ; 6, core ; c, entering fibre branching, and its two divisions passing to terminate
in the core at d ; C, an end-bulb treated with osmic acid, showing the cells of the
core better than B.
surrounded with a medullary sheath. Restoration of function in the nerve
may not occur for several months, during which time it is presumed the new
nerve-fibres are slowly finding their way along the course of those which
have been destroyed.
CHAPTER XIX.
THE ORGANS OF SPECIAL SENSE: THE SKIN, THE ORGAN OF
THE SENSE OF TOUCH, AND OF HEAT AND COLD; THE
TONGUE, THE ORGAN OF THE SENSE OF TASTE ; THE NOSE,
THE ORGAN OF THE SENSE OF SMELL; THE EAR, THE
ORGAN OF THE SENSE OF HEARING; THE EYE, THE ORGAN
OF THE SENSE OF SIGHT.
OUR sensations are both varied and numerous, and arise from
within and from without. Sensations arising from within our-
selves, such as feelings of fatigue, hunger, thirst, restlessness,
etc., and to which we can assign no particular place, we usually
speak of under the name of diffuse or subjective sensations.
Sensations produced by impressions made on a definite part of
the body, and only excited by some particular influence applied
to that part of the body, we usually speak of under the name of
special or objective sensations : such are sensations of touch, heat,
and cold, of taste and smell, and of sound and light.
Any portion of the body to which a sensation is thus restricted
is called a sensory organ, and of these special sensory organs
there are five, viz. : —
The skin, the organ of the sense of touch.
The tongue, the organ of the sense of taste.
The nose, the organ of the sense of smell.
The ear, the organ of the sense of hearing.
The eye, the organ of the sense of sight.
In order to be conscious of any sensation, it is necessary for
the end-organ (that is, the sensory organ which receives impres-
sions) to be placed in communication with the brain, which is
the seat of all sensation. If, for instance, the optic nerve, which
is the medium of communication between the visual centre in
the brain and the end-organ, the eye, be destroyed, the indi-
218
CHAP. XIX.] ORGANS OF SPECIAL SENSE. 219
vidual will be unable to see with that eye. In thinking of the
sensory organs, then, we must remember that they are structures
specially modified and adapted to receive certain impressions,
which impressions, when conveyed to the brain, give rise to definite
sensations.
The sense of touch. — The sense of touch, as also the sense of
heat and cold, is possessed more or less acutely by all parts of
the skin, and also by the mucous membrane, or internal skin,
lining the nose and mouth. We noted in the lesson on the
skin, that the sense of touch is most delicate in those parts
where the papillae of the true skin are most abundant and con-
tain the special nerve-endings called tactile corpuscles, as in the
tips of the fingers and toes (vide page 191). The feelings of
warmth and cold are also caused by exciting sensory nerves dis-
tributed to the skin, though they are probably distinct from
those which give rise to the sense of touch. The sense of
warmth and cold varies also in sensitiveness in different parts
of the body, and we involuntarily test the temperature of an
iron or of a poultice by holding it to the cheek, and when we
are cold we spread the palms of our hands to the fire.
If the nerves of the skin are unduly stimulated by severe
pressure, or by exposure to extremes of heat or cold, the sense
of touch and of temperature is lost in the sense of pain. This
is also the case if the nerves are too freely exposed, as when
the epidermis is removed by blistering, or in some other man-
ner, and the skin is left "raw."
The sense of taste. — The special organ of the sense of taste is
the tongue, which is a movable muscular organ covered with
mucous membrane. The mucous membrane closely resembles
the skin in structure, except that the papillae it contains are
more highly developed. The papillae project as minute promi-
nences and give the tongue its characteristic rough appearance.
Some of the papillae are simple and resemble those found in
the skin ; the remainder are compound,1 and are only found on
the surface of the tongue. Of these compound papillae there
are three varieties. The largest, the circumvallate papillce, are
about eight or ten in number, and form a V-shaped row near the
root of the tongue, with its open angle turned towards the lips.
1 A compound papilla is one large one bearing several smaller ones on its sur-
face.
220
ANATOMY FOR NURSES. [CHAP. XIX.
The next in size are the fungiform papillce,1 found principally on
the tip and sides of the tongue. The smallest and most numer-
ous are the filiform papillce, found all over the tongue, excepting
the root, and bearing on their free surface a form of ciliated
epithelium. In some animals the hair-like processes on the fili-
Fio. 128. — THE UPPER SURFACE OF THE TONGUE. 1, 2, circumvallate papillae;
3, fuiigil'orm papillae ; 4, filiform papillae ; 6, mucous glands.
form papillae are horny in structure, and their tongues are cor-
respondingly roughened, so that they supplement the teeth in
the bruising and crushing of food. In man these hair-like pro-
1 The fungiform papillae resemble fungi, having an expanded upper portion
resting on a short, thick pedicle. The circumvallate papillae resemble the
fungiform, except that they are surrounded by a wall of smaller papillae.
CHAP. XIX.] OKGANS OF SPECIAL SENSE. 221
cesses are exceedingly delicate, and seem to be specially con-
nected with the sense of touch, which on the tip of the tongue
is highly developed, and which serves to guide the tongue in its
variable and complicated movements.
In the circumvallate, some of the fungiform papillae, and
scattered also over the mucous membrane of the tongue and
soft- palate, are little clusters of cells lying in cavities of the
epithelium, called taste-buds. The bases of these cell-clusters,
or taste-buds, are supplied with nerve-fibres, and it is surmised
that they are more specially connected with the sense of taste
than the other portions of the mucous membrane covering the
tongue.
The special nerves of the sense of taste distributed to the
tongue are the glosso-pharyngeal, or ninth nerve, and the lin-
gual or gustatory, a branch of the fifth nerve. The former
supplies the back of the tongue, and section of it destroys taste
in that region ; the latter is distributed to the front of ' the
tongue, and section of it, similarly, deprives the tip of the
tongue of taste.
We often confound taste with smell. Substances which have
a strong odor, such as onions, are smelled as we hold them in our
mouths ; and if our sense of smell is temporarily suspended, as
it sometimes is by a bad cold in the head, we may eat garlic
and onions and not taste them. Hence the philosophy of hold-
ing the nose when we wish to swallow a nauseous dose.
The sense of smell. — The nose is the special organ of the
sense of smell. It consists of two parts, — the external feat-
ure, the nose, and the internal cavities, the nasal fossse. The
external nose is composed of a triangular framework of bone
and cartilage, covered by skin and lined by mucous membrane.
On its under surface are two oval-shaped openings — the nos-
trils— separated by a partition. The margins of the nostrils
are provided with a number of stiff hairs which arrest the pas-
sage of dust and other foreign substances carried in with the
inspired air.
The nasal fossae are two irregularly wedge-shaped cavities,
separated from one another by a partition or septum, and com-
municating with the air in front by the anterior nares or nostrils,
while behind they open into the back of the pharynx by the
two posterior nares. Fourteen bones enter into the formation
222
ANATOMY FOR, NURSES. [CHAP. XIX.
of the nasal cavities : the floor is formed by the palate and part
of the superior maxillary bones ; the roof is chiefly formed by
the perforated (cribriform) plate of the ethmoid bone, and by
the two small nasal bones ; and
in the outer walls we find,
in addition to processes from
other bones, the three scroll-
like turbinated bones. The
turbinated bones, which are ex-
ceedingly light and spongy,
project into the nasal cavities,
and divide them into three
incomplete passages from be-
fore backwards, — the supe-
rior, middle, and inferior me-
atus. The palate and superior
maxillary bones separate the
nasal and mouth cavities, and
FIG. 129. -VERTICAL LONGITUDINAL the cribriform plate of the eth-
SECTION OF NASAL CAVITY. 1, olfactory r . . ,
nerve; v, branch of fifth nerve; h, hard moid forms the partition be-
Palate- tween the cranial and nasal
cavities.
The mucous membrane (sometimes called the Schneiderian1
membrane), which closely covers 'the nasal passages, is thick-
est and most vascular over the turbinated bones. In some
nasal troubles it becomes much thickened and swollen and
occludes the nasal passages to such an extent as to compel us
to breathe through the mouth. It contains numerous mucous
glands which secrete mucus for the purpose of keeping the
membrane moist, — a condition which is essential to perfection
of the sense of smell.
The mucous membrane lining the nasal chambers is supplied
with nerve-fibres from the first or olfactory nerve, and also with
fibres of common sensation from the fifth nerve. The fibres
from the olfactory nerves are distributed exclusively to the
upper air-passages of the nose, the mucous membrane of which
is covered with a specially modified epithelium. These fibres
1 From Schneider, the first anatomist who showed that the secretions of the
nose proceeded from the mucous membrane, and not, as was formerly supposed,
from the brain.
CHAP. XIX.] OBGANS OF SPECIAL SENSE. 223
come directly from the brain through the cribriform plate, and
are essential to the sense of smell. Odorous particles in the air,
passing through the lower, wider air-passages, pass by diffusion
into the higher, narrower nasal chambers, and, falling on the
mucous membrane provided with olfactory nerve-endings, pro-
duce sensory impulses which, ascending to the brain, give rise
to the sensations of smell.
If we wish to smell anything particularly well, we sniff the
air up into the higher nasal chambers, and thus bring the odor-
ous particles more closely into contact with the olfactory nerves.
Each substance we smell causes its own particular sensation,
and we are not only able to recognize a multitude of distinct
odors, but also to distinguish individual odors in a mixed smell.
The sensation takes some time to develop after the contact of
the odorous stimulus, and may last a long time. When the
stimulus is repeated, the sensation very soon dies out, the
sensory terminal organs quickly becoming exhausted. Mental
associations cluster more strongly round sensations of smell
than round any other impressions we receive from without. A
whiff of fresh-mown grass ! What associations will it not con-
jure up for those happy mortals who spent their childish days
in country lanes and fields.
The sense of hearing. — The ear is the special organ of the
sense of hearing, and is made up of three portions, — the exter-
nal ear, the middle ear or tympanum, and the internal ear or
labyrinth.
. The external ear consists of an expanded portion, named
pinna or auricle, and the auditory canal or meatus.
The auricle is composed of a thin plate of yellow fibro-car-
tilage, covered with skin, and joined to the surrounding parts
by ligaments and a few muscular fibres. It is very irregular
in shape, and appears to be an unnecessary appendage to the
organ of hearing, except that the central depression, the concha,
serves to some extent to collect sound-waves, and to conduct
them into the auditory canal.
The auditory canal is a tubular passage, about an inch and a
quarter in length, leading from the concha to the drum-mem-
brane. It is slightly curved upon itself, so as to be higher in
the middle than at either end. It is lined by a prolongation of
the skin, which in the outer half of the canal is very thick and
224
ANATOMY FOR NURSES. [CHAP. XIX.
not at all sensitive, and in the inner half is thin and highly
sensitive. Near the orifice the skin is furnished with a few
hairs, and further inwards, with modified sweat-glands, the
ceruminous glands, which secrete a yellow, pasty substance,
resembling wax.
The middle ear or tympanum is a small, irregularly flattened
cavity, situated in the petrous portion of the temporal bone,
and lined with mucous membrane. It is separated from the
external auditory canal by the drum membrane (membrana
FIG. 130. — SEMI-DIAGRAMMATIC SECTION THROUGH THE RIGHT EAR. M, concha;
G, the external auditory canal ; T, tympanic, or drum-membrane ; P, tympanum,
or middle ear; o, oval window; r, round window. Extending from T too is seen
the chain of the tympanic bones; R, Eustachian tube; V, B, S, bony labyrinth; V,
vestibule; B, semicircular canal; S, cochlea; b, I, v, membranous labyrinth in semi-
circular canal and in vestibule. A, auditory nerve dividing into branches for vesti-
bule, semicircular canal and cochlea.
tympani), and from the internal ear by a bony wall in which
there are two small openings covered with membrane, — the
oval window or fenestra ovalis, and the round window or fenes-
tra rotunda. The cavity of the middle ear is so small that
probably five or six drops of water would completely fill it.
It communicates below with the pharynx by the small passage
called the Eustachian tube, through which air enters the cavity
and serves to keep the atmospheric pressure equal on each
side of the drum-membrane. The middle ear also communi-
cates above with a number of bony cavities in the mastoid por-
CHAP. XIX.] ORGANS OF SPECIAL SENSE. 225
tion of the temporal bone.1 The cavities, called mastoid cells,
are lined with mucous membrane, which is continuous with that
covering the" cavity of the tympanum.
Stretching across the tympanic cavity is a chain of tiny mov-
able bones, three in number, and named from their shape
the malleus or hammer, the incus or anvil, and the stapes or
stirrup. The hammer is firmly attached to the drum-mem-
brane, and the stirrup is fastened into the oval window (also
covered by membrane) leading into the inner ear. The anvil is
placed between the hammer and stirrup, and attached to both
by delicate articulations. These little bones are set in motion
with every movement of the drum-membrane. Vibrations of
the membrane are communicated to the hammer, taken up by
the anvil and transmitted to the stirrup, which is driven slightly
forward, and sets in motion the membrane covering the oval
opening leading into the internal ear.
The internal ear or labyrinth receives the ultimate termina-
tions of the auditory nerve, and is, therefore, the essential part
of the organ of hearing. It consists of (1) a bony labyrinth,
which is composed of a series of peculiarly shaped cavities, hol-
lowed out of the petrous portion of the temporal bone, and
named from their shape the vestibule, the semicircular canals,
and cochlea (snail-shell). This bony labyrinth is lined by a
serous membrane, which secretes a watery fluid called the peri-
lymph ; and lying within the bony labyrinth and peri-lymph is
(2) a membranous labyrinth, which is composed of a series of
sacs or tubes, fitting more or less closely within the vestibule,
semicircular canals, and cochlea. The membranous labyrinth
is filled with a watery fluid, called the endo-lymph, and is lined
for the most part by specially modified epithelium cells, which
are connected with the terminations of the auditory nerve.
We may conceive of the internal ear as a bony cavity, elabo-
rately tunnelled from the expanded entrance or vestibule into
semicircular canals above, and into a canal resembling a snail's
shell below. In this bony labyrinth is a certain amount of
fluid, and a membranous bag, drawn out and expanded at inter-
vals to fit more or less closely within the bony labyrinth. This
membranous bag contains fluid, and is lined by a most highly
1 The mastoid portion of the temporal bone is that rounded mass of bone
which one readily distinguishes behind the auricle.
226 ANATOMY FOK NUKSES. [CHAP. XIX.
specialized epithelium, some of the cells of which have hair-like
processes projecting into the fluid, others have tiny grains of
calcareous sand 1 attached to their surfaces, and all of them are
connected with the thousands of nerve-fibres into which the
auditory nerve divides after entering the internal ear. The
construction of the whole ear and its position in the centre of a
bone is for the purpose of protecting this delicate and highly
organized membrane, by means of which alone sound-impres-
sions can be advantageously conveyed to the brain and give rise
to the sensation of hearing.
All bodies which produce sound are in a state of vibration
and communicate their vibrations to the air with which they
are in contact, and thus the air is thrown into waves, just as a
stick waved backwards and forwards in water throws the water
into waves.
When air-waves, set in motion by sonorous bodies, enter the
external auditory canal, they set the drum-membrane vibrating,
stretched membranes taking up vibrations from the air with
great readiness. These vibrations are communicated to the
chain of tiny bones stretching across the middle ear, and their
oscillations cause the membrane leading into the internal ear to
be alternately pushed in and drawn out, and vibrations are in
this way transmitted to the peri-lymph. Each vibration com-
municated to the peri-lymph travels as a wave over the ves-
tibule, semicircular canals, and cochlea, and is transmitted
through the membranous walls to the endo-lymph. The vibra-
tions of the endo-lymph are communicated to the specially modi-
fied cells connected with the endings of the auditory nerve, and
nervous impulses are conveyed by the auditory nerve to those
parts of the brain, stimulation of which gives rise to the sensa-
tion of sound.
The effect produced by a sonorous vibration continues for a
short time after the cessation of its cause. Usually the interval
between two different impulses is sufficient to allow the first
impression to disappear before the second is received, and the
ear distinguishes them in succession. But if they follow each
other at equal intervals, with a certain rapidity, they produce
1 In the walls of the vestibule are two small masses, called otoliths, which are
composed of grains of calcareous sand. It is not known what special part these
otoliths play in the production of sound.
CHAP. XIX.] ORGANS OF SPECIAL SENSE. 227
the impression of a continuous sound ; and this sound has a
higher or lower pitch, according to the rapidity of its vibra-
tions. It has been discovered that sonorous impulses following
each other with a rapidity of less than sixteen times per second,
are separately distinguishable ; but above that frequency they
are merged into a continuous sensation. When the sonorous
impulses are repeated at irregular intervals, the only characters
perceptible in the sound are its intensit}r and quality. But if
they succeed each other at regular intervals, the sound pro-
duced has a position in the musical scale as a high or low note.
The more frequent the repetitions, the higher the note ; but a
limit is at last reached, at which the ear fails to perceive the
sound, and an excessively high note is therefore inaudible.
Sonorous vibrations, perceptible to man as musical notes, range
between sixteen per second for the lowest notes, and 38,000 for
the highest. (Dalton.)
The sense of sight. — The eye is the special organ of the sense
of sight, and consists of the eyeball, or eye proper, and of acces-
sory protective appendages, such as the eyebrows, eyelids, lach-
rymal glands, etc.
The eyeball is contained in a bony cavity, the orbit, which is
padded with fat and lined with a membranous capsule, — the
capsule of Tenon. This capsule is a serous sac, one layer of
which is attached to the posterior portion of the eyeball, while
the other lines the orbital cavity: in this way the eyeball is
isolated from surrounding structures, and free movement with-
out friction is insured. The orbit is shaped like a four-sided
pyramid ; the apex, directed backwards and inwards, is pierced
by a large opening, — the optic foramen, — through which pass
the nerves and blood-vessels distributed to the eyeball. The
base of the orbit, directed outwards and forwards, forms a strong
bony edge for protecting the eyeball from injury.
The eyeball is spherical in shape, but its transverse diameter
is less than the antero-posterior, so that it projects anteriorly,
and looks as if a section of a smaller sphere had been engrafted
on the front of it.
The eyeball is composed of three coats or tunics, and contains
three refracting media or humours. They are as follows : —
Tunics. — 1. Sclerotic and cornea.
2. Choroid, iris, and ciliary processes.
3. Retina.
228 ANATOMY FOR NUKSES. [CHAP. XIX.
Befr acting media. — 1. Aqueous.
2. Crystalline lens and capsule.
3. Vitreous.
The sclerotic (derived from a Greek word signifying hard)
covers the posterior five-sixths of the eyeball. It is composed
of a firm, unyielding, fibrous membrane, thicker behind than in
front, and serves to protect the delicate structures contained
FIG. 131. — THE LEFT EYEBALL IN HORIZONTAL SECTION FROM BEFORE BACK.
1, sclerotic; 2, junction of sclerotic and cornea; 3, cornea; 4, 5, conjunctival mem-
brane ; 7, ciliary muscle ; 10, choroid ; 11, 13, ciliary processes ; 14, iris ; 15, retina ;
16, optic nerve; 17, artery entering retina; 18, fovea centralis; 19, region where
sensory part of retina ends ; 26, 27, 28, are placed on the lens ; 28, suspensory liga-
ment placed around lens; 29, vitreous humour ; 30, aqueous humour in anterior
chamber.
within it. It is opaque, white and smooth externally, and
behind is pierced by the optic nerve. Internally it is stained
brown where it comes in contact with the choroid coat. The
cornea (derived from Latin cornu, horn, and therefore also sig-
nifying hard) covers the anterior sixth of the eyeball. It is
directly continuous with the sclerotic coat, which, however,
overlaps it slightly above and below, as a watch-crystal is over-
lapped by the case into which it is fitted. The cornea, like the
CHAP. XIX.] OKGANS OF SPECIAL SENSE. 229
sclerotic, is composed of fibrous tissue, which is both firm and
unyielding, but, unlike the sclerotic, it has no colour, and is
perfectly transparent: it has been aptly termed the "window
of the eye." Both the cornea and the anterior portion of the
sclerotic are covered by reflections of the mucous membrane
lining the eyelids. This is called the conjunctiva, and, kept
well lubricated by the secretions of the eye, gives the eyeball
its peculiar shining and glossy aspect. The sclerotic is supplied
with very few blood-vessels, and the existence of nerves in it is
doubtful ; while the cornea has no blood-vessels, but is well
supplied with nerves.
The choroid, or vascular coat of the eye, is a thin dark-brown
membrane lining the inner surface of the sclerotic. It is com-
posed of connective tissue, the cells of which are large and
filled with pigment, and it contains a close network of blood-
vessels. It extends to within a short distance of the cornea,
and then is folded inwards and arranged in radiating folds, like
a plaited ruffle, around the lens and just behind the edge of
the cornea. The choroid coat, properly speaking, terminates
anteriorly in the ciliary processes, arranged, as above stated, in
a radiating circle round the lens ; but closely connected with
the anterior margin of the choroid is the iris.
The iris (iris, rainbow) is a coloured, fibre-muscular curtain
hanging in front of the lens and behind the cornea. It is
attached at its circumference to the choroid, with which it is
practically continuous, and is also connected to the sclerotic
and cornea at the point where they join one another. Except
for this attachment at its circumference, it hangs free in the
interior of the eyeball. In the middle of the iris is a circular
hole — the pupil — through which light is admitted into the
eye-chamber. The iris, like the choroid, is composed of con-
nective tissue containing a large number of pigment cells and
numerous blood-vessels. It contains in addition two sets of
plain muscular fibres. One set forms a flat band round the
margin of the pupil, and is called the sphincter or contractor
of the pupil ; the other set consists of radiating fibres converg-
ing from the circumference to the centre, and is called the
dilator of the pupil. The action of these muscle-fibres is
affected by light. Under the influence of a bright light the
pupil involuntarily contracts so that less light is admitted into
230
ANATOMY FOR NURSES. [CHAP. XIX.
the eye-chamber; in a dim light the pupil involuntarily dilates
to admit as much light as possible. The posterior surface of
the iris is covered by a thick layer of pigment-cells designed
to darken the curtain and prevent the entrance of light. The
anterior surface of the iris
is also covered with pig-
ment cells, and it is chiefly
these latter which cause the
beautiful colours seen in the
iris. The different colours
of eyes, however, are mainly
due to the amount, and not
to the colour, of the pig-
ment deposited.
The retina, the innermost
coat of the eyeball, is the
most essential part of the
organ of sight, since it is
the only one directly sensi-
tive to light. The sclerotic
is the protective, the choroid
the vascular or nutritive,
and the retina is the visual
or perceptive, layer of the
eyeball. It forms a nearly
transparent membrane situ-
ated between the inner sur-
face of the choroid and the
outer surface of the vitre-
ous humour, and extending
FIG 132. -DIAGRAMMATIC SECTION OF from the entrance of the
THE HUMAN KETINA. (M. Schultze.) a,
inner surface; b, internal limiting mem- OptlC nerve to the COm-
brane; 1, layer of nerve-fibres; 2, layer of mencement of the ciliary
processes, where it termi-
nates by an indented border,
the ora serrata. It is composed of eight layers and two limiting
membranes, as shown in the accompanying figure (Fig. 132).
The most essential of these layers are the first and second, —
the layer of nerve-fibres and the layer of nerve-cells, — and the
seventh layer, — the layer of the rods and cones. The layer of
nerve-cells ; c, external limiting membrane ;
7, layer of rods and cones ; 8, pigment cells ;
d, outer surface.
CHAP. XIX.] ORGANS OF SPECIAL SENSE. 231
nerve-fibres is formed by the expansion of the optic nerve after
it has passed through the sclerotic and choroid coats at the back
of the eye. At its entrance it forms a slight prominence, and
then radiates latterly in every direction in the form of a closely
set layer of fine fibrils. The second layer, or layer of nerve-
cells, consists for the most part of bipolar l cells, processes from
which extend into the layer above and below.
The layer of rods and cones is the most remarkable of all the
retinal layers; it is composed of elongated nucleated cells,
which are supposed by some authorities to be highly specialized
epithelium cells : they are directly concerned in producing the
sensation of light. Rays of light produce no effect upon the
optic nerve without the intervention of the rods and cones.
This is proved by the fact that at the entrance of the optic
nerve there are no rods and cones, and this spot is quite blind,
rays of light falling upon it producing no sensation. There is
one point of the retina which is of great importance, and that is
the macula lutea, or yellow spot. It is situated about j1^- of an
inch to the outer side of the entrance of the optic nerve. In its
centre is a tiny pit (fovea centralis) which is the centre of
direct vision ; that is, it is the part of the retina which is always
turned towards the object looked at. From this point the sen-
sitiveness of the retina grows less and less in all directions. In
the fovea centralis the rods are highly developed, but most of
the other layers of the retina are wanting.
Light may be described as consisting of vibrations in the ether
which pervades space. These ethereal vibrations enter the eye
through the cornea, pass on through the pupil and refracting
media, and strike on the retina. Here they excite the rods and
cones (cell-bodies specially adapted for receiving stimulation
from rays of light), and these pass on their stimulation to the
fibres of the optic nerve, which in turn transmit the stimulus to
the visual centre in the brain, and the sensation and perception
of light is produced.
Behind the layer of rods and cones, and lying on the choroid,
is a beautiful mosaic layer of pigment cells containing a purple
substance which stains the rods, and is constantly bleached by
the action of light and regenerated in the dark.
The refracting media of the eye. — The interior of the eyeball
1 A bipolar cell is a cell having two processes.
232 ANATOMY FOE NUESES. [CHAP. XIX.
is divided into two chambers by the crystalline lens and iris.
The " anterior chamber," the portion in front of the iris, is rilled
with a colourless, transparent watery fluid, the aqueous humour.
The "posterior chamber" is filled with a semi-fluid gelatinous
substance, the vitreous humour or body, so called from its glassy
and transparent appearance. Its refractive power, though
slightly greater than that of the aqueous humour, does not differ
much from that of water. It distends the greater part of the
sclerotic, supports the retina, which lies upon its surface, and
preserves the spheroidal shape of the eyeball.
The crystalline lens is a transparent refractive body, with con-
vex anterior and posterior surfaces, placed directly behind the
pupil, where it is retained in position by the counterbalancing
pressure of the aqueous humour and vitreous body, and by its
own suspensory ligament. It is a fibrous body, composed of
long riband-shaped fibres and enclosed in an elastic capsule.
Its refractive power is greater than that of the aqueous or
vitreous humour, and it acts by virtue of its double-convex
form as a converging lens, bringing parallel or diverging rays
to a focus on the posterior surface of the retina. The function
of the crystalline lens is to give perception of form and outline.
If the eye consisted only of a sensitive retina, impressions of
light could be received, but the form of objects would not be
distinguished. By focussing the rays emanating from an ex-
ternal object, the crystalline lens produces a distinct inverted
image of the object on the retina.
The action of the lens, in thus focussing the rays of light at
a particular point, may be illustrated in the following manner :
If a sheet of white paper be held at a short distance from a
candle-flame, in a room with no other light, the whole of the
paper will be moderately and uniformly illuminated by the
diverging rays. But if a double-convex lens, with suitable cur-
vatures, be interposed between the paper and the light, the
outer portions of the paper will become darker, and its central
portion brighter, because a portion of the rays are diverted
from their original course and bent inward. By varying the
distance of the lens from the paper, a point will at last be
found where none of the light reaches the external parts of the
sheet, but all of it is concentrated upon a single spot ; and at
this spot will be seen a distinct image of the candle and its
flame.
CHAP. XIX.] ORGANS OF SPECIAL SENSE. 233
Perception of the figure of external objects therefore depends
on the action of the crystalline lens in converging all the rays,
emanating from a given point, to a focus on the retina. When
the lens of the eye is too convex, and its refractive power
excessive, the rays of light converge too soon and cross one
another before reaching the retina ; consequently, the image
produced is not concentrated and distinct, but, dispersed more
or less over the surface of the retina, is diffused and dim. On
the other hand, if the lens
is too flat, the rays do not
converge soon enough, and
the image is again diffused
and indistinct. To remedy
a too great convexity of the
lens in the short-sighted or
myopic eye, concave specta-
cles are used to disperse the
rays ; to remedy the flattened
lens in the hypermetropic or
long-sighted eye, we employ
convex glasses to concen-
trate and focus the rays
more quickly.
A normal eye is capable
of distinct vision through- FlG 133 _ DlAGBAM ILLUSTRATING RAYS
OUt an immense range. We OF LIGHT CONVERGING IN A NORMAL EYE,
.7,. „ (A), A MYOPIC EYE, (B), AND A HYPER-
can see the stars millions ot METROPIC EYE (C).
miles away, and with the
same eye, though not at the same time, we can see objects within
a few inches of us. To be able to see objects millions of
miles away and within a short range, the eye has to accom-
modate or adjust itself to different distances. This ac-
commodation is accomplished mainly by the lens changing its
convexity. In accommodation for near objects, the lens becomes
more convex and the pupil of the eye likewise contracts. This
convexity is brought about by muscular effort,1 and is always
more or less fatiguing. The accommodation for distant objects
is a passive condition, the convexity of the lens being unaltered
1 Connected with the lens are tiny muscles, — the ciliary muscles, — contraction
of which alters the shape of the lens.
234 ANATOMY FOE, NUESES. [CHAP. XIX.
and the pupil of the eye dilated, and it is on this account that
the eye rests for an indefinite time upon remote objects without
fatigue.
The eyeball is often compared to a photographer's camera.
It is essentially a hollow spherical box filled with fluids, having
its interior surface blackened by pigment, and containing a
system of lenses by means of which images can be formed, and
a screen upon which they can be received. In front is a cur-
tain or diaphragm (the iris), with a variable central aperture
(the pupil) to regulate the amount of light admitted.
The colour of light is considered to be analogous to the pitch
of sound. As the latter is determined by the number of vibra-
tions of the atmosphere which strike the ear in a second, so the
former depends on the waves of ether which strike the retina in
a second. The lowest note of an ordinary musical scale has,
as we have already remarked, sixteen vibrations per second;
the highest, 38,000 per second. The number of ether-waves
which strike the retina in a second to produce the sensation of
red (which lies at the bottom, so to speak, of the colour-scale)
is estimated at 474,439,680,000,000. The number required to
cause the sensation of violet, which lies at the other extreme of
our colour-perception, is estimated at 699,000,000,000,000 !
The muscles which move the eyeball are the four straight or
recti and the two oblique. They have been sufficiently de-
scribed on page 58.
The appendages of the eye are the eyebrows, eyelids and
lachrymal glands.
The eyebrows are composed of two arched eminences of
thickened skin, connected with three muscles, which by their
action control to a limited extent the amount of light admitted
into the eye. The eyebrows are furnished with numerous
short, thick hairs, lying obliquely on the surface.
The eyelids are two folds, projecting from above and below
in front of the eye. They are covered externally by the skin
and internally by a mucous membrane, the conjunctiva, which
is reflected from them over the globe of the eye. They are
composed for the most part of connective tissue, which is
dense and fibrous under the conjunctiva, where it is known
as the tarsus.
Embedded in the tarsus is a row of elongated sebaceous glands
CHAP. XIX.] ORGANS OF SPECIAL SENSE.
235
(the Meibomian glands *), the ducts of which open on the edge
of the eyelid. The secretion of these glands is provided to
prevent adhesion of the eyelids.
Arranged in a double or triple row at the margin of the lids
are the eyelashes ; those of the upper lid, more numerous and
longer than the lower, curve upwards ; those of the lower lid
curve downwards, so that they do not interlace in closing the
lids. The upper lid is attached to a small muscle which is
called the elevator of the upper lid; and arranged as a sphincter
around both lids is the orbicularis palpelrarum muscle, which
closes the eyelids, and is the direct antagonist of the elevator of
the upper lid.
The slit between the edges of the lids is called the palpe-
bral fissure. It is the size of this fissure which causes the
appearance of large and small eyes, as the size of the
lobe itself varies but little. The outer angle of this fissure is
called the external canthus ; the inner angle, the internal can-
thus.
The eyelids are obviously provided for the protection of the
eye ; movable shades which by their closure exclude light, par-
ticles of dust, and other
injurious substances.
The lachrymal gland is
a compound gland, closely
resembling the salivary
glands in structure. It
secretes the tears, and is
lodged in a depression at
the outer angle of the
orbit. It is about the size
and shape of an almond.
Its ducts run obliquely
beneath the conjunctiva,
and open by a series of
minute orifices upon the
upper surface of the eye.
After passing over the surface of the eyeball, the tears are carried
away through minute openings in the inner angle of the eye into
1 By inverting the eyelids, these glands may be seen through the conjunctiva
lying in parallel rows.
FIG. 134. — THE LACHRYMAL APPARATUS.
236 ANATOMY FOR NURSES. [CHAP. XIX
the lachrymal sac, which is the upper dilated portion of the nasal
duct.
The nasal duct is a membranous canal, about three-quarters
of an inch in length, which extends from the lachrymal sac to
the inferior meatus of the nose, into which it opens by a slightly
expanded orifice.
The tears consist of water containing a little salt and albu-
min. They are ordinarily carried away as fast as formed, but
under certain circumstances, as when the conjunctiva is irri-
tated, or when painful emotions arise in the mind, the secretion
of the lachrymal gland exceeds the drainage power of the nasal
duct, and the fluid, accumulating between the lids, at length
overflows, and runs down the cheeks.
CHAPTER XX.
FEMALE GENERATIVE ORGANS.
THE internal female generative organs are vagina, uterus,
Fallopian tubes, and ovaries.
The vagina. — The vagina is a distensible and curved musculo-
membranous canal, extending from the vulva to the uterus.
The posterior wall is about three and a half inches long, while
the anterior wall is only three inches. The front or anterior
wall is united by connective tissue with the posterior walls of
the bladder and urethra, the partition or septum between the
bladder and vagina being called the vesico-vaginal, and that
between the urethra and vagina, the urethro-vaginal, septum.
And, if we divide the posterior wall of the vagina into five
sections, we find that the middle three-fifths is connected with
the rectum, the united walls forming the recto-vaginal septum;1
the lower fifth is separated from the rectum and is joined to the
perineum;2 while the upper fifth extends up behind the neck of
the uterus.
The vagina is made up of three coats, an outer, fibrous;
middle, muscular ; and inner, mucous. The muscular coat in-
creases during pregnancy, 'and the mucous coat is arranged in
transverse folds or rugae, which allow of dilatation of the canal
during labour.
The uterus. — The uterus is a thick -walled, hollow, pear-
shaped organ, situated in the middle of the pelvic cavity. Its
upper end is a little below the level of the superior strait of the
pelvis (vide page 43) ; its lower end projects into the vagina.
1 Perforations of the vesico-vaginal and recto-vaginal partitions constitute
vesico-vaginal and recto-vaginal fistulae.
2 The perineum is a triangular section of tissue, made up of muscles strength-
ened with fascia, placed between the rectum and vagina, and forming the floor
of the pelvis.
237
238 ANATOMY FOR NURSES. [CHAP. XX.
The bladder lies in front of it ; the rectum, behind ; the vagina,
below; and the small intestine rests upon it above. Its length
is roughly estimated to be about three inches; its greatest
width, one and one-half inches; and its thickness, one inch.
At the end of pregnancy it attains the length of a foot or more,
and measures about eight to ten inches transversely.
The uterus is divided for purposes of description into three
FIG. 135. — SECTION OF FEMALE PELVIS, SHOWING RELATIVE POSITION OF VISCERA.
parts, the fundus, body, and neck. The fundus is the rounded
portion projecting above a line drawn transversely through the
upper part of the organ. The body is the portion extending
from the rounded section, the fundus, to the constricted section,
the neck. The neck or cervix extends from the body of the
uterus into the vagina.
Owing to the thickness of its walls, the cavity of the uterus
CHAP. XX.] FEMALE GENERATIVE ORGANS. 239
is comparatively small. The cavity is triangular in shape
and has three openings, one at each upper angle, communicating
with the Fallopian tubes, and one, the os internum, or internal
mouth, opening into the cavity of the cervix below. The
cavity of the cervix, which is, of course, continuous with the
cavity in the body, is constricted above, where it opens into
the body by means of the os internum, and below, where it
opens exteriorly by means of the os extern um,1 or external
mouth. Between these two openings, the cavity of the cervix
is somewhat enlarged.
The walls of the uterus consist mainly of bundles of plain
muscular tissue, arranged in layers which run circularly, longi-
tudinally, spirally, and cross and interlace in every direction.
A part of the external surface is covered by a portion of the
peritoneum in the form of a broad ligament, and the inner sur-
face is lined by a mucous membrane. This mucous membrane
is continuous with that lining the vagina and Fallopian tubes.
It is highly vascular, provided with numerous mucous glands,
and is covered with ciliated epithelium.
The uterus is abundantly supplied with blood-vessels, lym-
phatics, and nerves. The blood reaches the uterus by means of
the uterine arteries from the internal iliacs, and the ovarian
arteries from the aorta. Where the neck joins the body of the
uterus, the arteries from both sides are united by a branch
vessel, called the circumflex artery. If this branch is cut dur-
ing a surgical operation, or a tear of the neck during parturi-
tion extends so far as to sever it, the hemorrhage is very
profuse. The arteries are remarkable for their tortuous course
and frequent anastomoses. The veins are of large size and cor-
respond in their behaviour to the arteries.
During pregnancy all the tissues of the uterus become much
enlarged, undergoing what is called a physiological hypertrophy.
The uterus increases in weight from two or three ounces to two
or three pounds. After parturition, it goes back to nearly its
former size. The tissues all go through a gradual shrinkage, or
what is called a physiological atrophy. The enlarged muscles
especially undergo fatty degeneration and absorption, called
"involution," in contradistinction to "evolution" or develop-
1 The os externum is bounded by two folds or lips of the mucous membrane,
the anterior of which is thick, and the posterior narrow and long.
240 ANATOMY FOR NUKSES. [CHAP. XX.
me lit. This process of involution is not accomplished under
six weeks, and sometimes requires longer.
The uterus is not firmly attached or adherent to any part of
the skeleton. It is, as it were, suspended in the pelvic cavity,
and kept in position by ligaments. A full bladder pushes it
backward ; a distended rectum, forward. It alters its position,
by gravity, with change of posture. During gestation it rises
into the abdominal cavity.
The uterus has five pairs of ligaments attached to it, the
chief of which are the broad and round ligaments. The broad
ligaments are folds of peritoneum slung over the front and back
of the uterus, and extending laterally to the walls of the pelvis.
The anterior fold covers the front of the uterus as far as the
middle of the cervix, when it turns up and is reflected over
^risOe patted thrva&
FIG. 136.— THE UTERUS AND ITS APPENDAGES. ANTERIOR VIEW.
the back wall of the bladder. The posterior fold covers the
back of the uterus, and extends far enough below to also
cover the upper one-fifth of the back wall of the vagina, when
it turns up and is reflected over the anterior wall of the rectum.
Thus the uterus, with, and between its two broad ligaments,
forms a transverse partition in the pelvic cavity, the bladder,
vagina, and urethra being in the front compartment, and the
rectum in the back compartment. The round ligaments are two
rounded nbro-muscular cords, situated between the folds of the
broad ligament. They are about four and a half inches long,
and extend from the upper angle of the uterus forwards and
outwards to be inserted into the vulva.
Fallopian tubes. — The Fallopian 1 tubes or oviducts are pro-
1 Named after Fallopius, an Italian anatomist.
CHAP. XX.] FEMALE GENERATIVE OKGANS. 241
vided for the purpose of conveying the ova from the ovaries
into the cavity of the uterus. They are two in number, one on
each side, and pass from the upper angles of the uterus in a
somewhat tortuous course between the folds and along the
upper margin of the broad ligament, towards the sides of the
pelvis. Each tube is about four inches in length. Its canal is
exceedingly small, and begins at the upper angle of the uterus
by a minute opening which will hardly admit of a fine bristle.
It continues narrow along the inner half of the tube, and then
gradually widens into a trumpet-shaped extremity, which be-
comes contracted at its termination. The margins of the free
trumpet-shaped extremity are frayed out into a number of
fringe-like processes, called fimbrice and one of these processes,
longer than the rest, is connected with the outer end of the
ovary.
The Fallopian tube consists, like the uterus, of three coats :
the external or serous coat, derived from the peritoneum ; the
middle or muscular coat, having a layer of longitudinal and of
circular fibres ; and the internal or mucous coat, continuous at
the inner end with the mucous lining of the uterus, and at the
distal end with the serous lining of the abdominal cavity. This
is the only instance in the body in which a mucous and serous
lining are continuous with one another.
When the ovum is ready for entrance into the Fallopian
tube, the fimbrise of the free end grasp the ovary, the tiny
germ-cell is safely conducted into the trumpet-shaped ex-
tremity, and is thence carried along by the peristaltic motion
of the oviduct into the uterus. This transmission of the cell is
also assisted by the ciliated epithelium lining the tube, the
motion of the cilia wafting it onwards.
The ovaries. — The ovaries are two small almond-shaped
bodies* situated one on each side of the uterus, between the
anterior and posterior folds of the broad ligament, and below
the Fallopian tubes. Each ovary is attached by its inner end
to the uterus by a short ligament — the ligament of the ovary ;
and by its outer end to the Fallopian tube by one of the fringe-
like processes of the fimbriated extremity. The ovaries each
measure about one and a half inches in length, three-fourths of
an inch wide, and one-third of an inch thick, and weigh from
one to two drachms. Their function is to produce, develop,
242
ANATOMY FOR NURSES. [CHAP. XX.
and mature the ova, and to discharge them when fully formed
from the ovary.
The ovaries consist of a framework of connective and muscu-
lar tissue, usually called the stroma or bed of the organ ; and of
FIG. 137. — SECTION OF AN OVARY. (Waldeyer.) a,, germ-epithelium ; 6, egg-
tubes ; c, c, small follicles ; d, more advanced follicle ; e, discus proligerus and ovum ;
/, second ovum in same follicle (this occurs but rarely) ; g, outer tunic of the follicle ;
h, inner tunic; i, membrana granulosa; k, collapsed retrograded follicle; I, I, blood-
vessels; y, involuted portion of the germ-epithelium of the surface; z, place of the
transition from peritoneal to germinal or ovarian epithelium.
numerous vesicles or follicles of different sizes, called the
Graafian follicles.
The stroma contains many blood-vessels and lymphatics. The
outer portion is more condensed than the interior, and the whole
CHAP. XX.] FEMALE GENERATIVE ORGANS. 243
is covered by a peculiar layer of columnar epithelium-cells,
called germinal epithelium.
The Graafian follicles are cavities dotted about in the stroma
in large numbers. The smaller ones lie near the surface. The
larger are more deeply imbedded, and only approach the sur-
face when they are ready to discharge their contents. The
follicles have each their own proper wall or tunic, derived from
the connective tissue of the stroma, and each is lined by a layer
or layers of granular epithelium-cells, and contains an ovum.
The granular layer of cells, closely lining the cavity of the
follicle, is termed the membrana granulosa, but at one or other
side it is heaped up into a mass of cells which projects into the
cavity of the follicle and envelops the ovum. This mass of
cells which immediately surrounds the ovum is called the
discus proligerus.
As the follicle matures, fluid collects in the cavity, and,
increasing in amount, the follicle gradually becomes larger and
more tense. It now approaches the surface and begins to form
a protuberance like a small boil upon the outside of the ovary.
Finally the wall of the ovary and the wall of the follicle burst
at the same point, and the fluid (liquor folliculi) containing the
ovum, with the loose, irregular mass of cells, the discus pro-
ligerus, clinging to it, is set free. At the moment of rupture,
the ovum is received by the Fallopian tube and afterwards con-
veyed to the uterus. After the follicle has discharged its con-
tents, it has done its work, and it passes through a series of
changes which are more or less persistent, but eventually it is
obliterated and disappears. Thus in the very same ovary some
of the follicles are mature, or approaching maturity ; others are
undergoing development; while others are retrograding and
disappearing.
The ova are formed from the germ-epithelium on the surface
of the ovary, the cells of which become enlarged and dip down
into the stroma in the form of little elongated masses. From
these groups of cells the Graafian follicles and the ova are pro-
duced. The ovum is a highly developed cell about -j^g- inch
in diameter. It has (1) a thick, surrounding envelope or
membrane, called the vitelline membrane or zona pellucida ;
(2) within the membrane or cell-wall is the protoplasm of
the cell, rilled with fatty and albuminous granules, and usually
244 ANATOMY FOR NURSES. [CHAP. XX.
called the vitellus or yolk ; (3) imbedded in the vitellus or yolk
is a transparent, sharply outlined nucleus, the germinal vesicle ;
and (4) in the germinal vesicle is a small dark nucleolus, the
germinative spot.
It is impossible for us to trace the growth and development
of a fecundated ovum. The subject is too complicated for us
to attempt to describe it in a book of this kind, and we shall,
therefore, content ourselves with briefly describing the first two
or three steps.
Soon after leaving the ovary, the germinal vesicle and ger-
minal spot in a fecundated ovum disappear, and the protoplasm
begins to divide inside the vitelline membrane into two halves,
in each of which appears a nucleus. The halves divide into
quarters, the quarters into eighths, and so the subdivision con-
tinues until a great number of minute cells are produced, which
soon arrange themselves, close to each other like bricks in a
wall, upon the inner surface of the vitelline membrane. The
cells thus in close contact with one another form a membrane,
called the epiblast. Upon this membrane a second one soon
appears, formed in the same way and lining its inner surface.
This is called the hypoblast. Subsequently a third membrane,
the mesoblast, is developed between the epi- and hypoblast, and
from these three membranes all the tissues and complicated
structures of the body are evolved.
Upon the arrival of the ovum in the uterus, it is grafted
upon the mucous membrane. It usually lodges upon the upper
surface of the uterus, between two folds of the mucous lining,
which soon grow up all around it, and, as it were, bury the germ
in a circular grave. From the thickened mucous membrane
lying between the ovum and the uterine wall, the placenta is
ultimately formed for the nourishment of the embryo.
The mammary glands. — The mammary gland is a compound
gland, formed of branching ducts ending in secretory recesses.
The whole organ is divided by connective tissue partitions into
a number of lobes, each of which possesses its own excretory
duct opening by a separate orifice upon the surface of the
nipple, the gland being in fact not a single gland, but several
glands bound together. Just before opening on to the nipple,
each excretory duct is widened into a flask-shaped enlarge-
ment.
CHAP. XX.] FEMALE GENERATIVE ORGANS. 245
The walls of the ducts and of the secreting recesses are
formed of a basement membrane lined by epithelium-cells.
During lactation the secreting cells become much enlarged,
and fatty globules are formed within them. The fatty glob-
ules appear to be set free by the breaking down of the inner
part of the cell, the protoplasm becoming dissolved also, and
forming the proteid substances of the milk. At the beginning
of lactation the cells are imperfectly broken up, so that numerous
cells containing comparatively large masses of fat (the colostrum
corpuscles) appear in the secretion.
Human milk has a specific gravity of from 1028 to 1034, and
when quite fresh possesses a slightly alkaline reaction. Its
average composition in every 100 parts is : —
Proteids 2
Fats 2.75
Sugar 5
Salts 0.25
Water 90
100
(Foster.)
GLOSSAEY.
Abdu'cens. [From the Lat. ab, "from," and duco, to "lead."] A term ap-
plied to the sixth pair of cranial nerves which supply the external recti
(abductor), muscles of the eye.
Acetab'ulum. [From the Lat. acetum, " vinegar."] A name given to the
cavity in the os innominatum, resembling in shape an old-fashioned
vinegar vessel.
Acro'mion. [From the Gr. akron, "summit," and omos, the "shoulder."]
The triangular-shaped process at the summit of the scapula.
Ad'enpid. [From the Gr. aden, a "gland," and eidos, "form" or "resem-
blance."] Pertaining to,, resembling a gland.
Ad'ipose. [From the Lat. adeps, "fat."] Fatty.
Afferent. [From the Lat. ad, " to," and/ero, to " bear," to " carry."] Bear-
ing or carrying inwards, as from the periphery to the centre.
Ag'minated. [From the Lat. agmen, a " multitude," a " group."] Arranged
in clusters, grouped.
. Albu'min. [From the Lat. albus, " white."] Animal albumin is the chief
solid ingredient in the white of eggs.
Albuminu'ria. [A combination of the words "albumin" and "urine."]
Presence of albumin in the urine.
Aliment'ary. [From the Lat. alimentum, "food."] Pertaining to aliment or
food.
Alimenta'tion. The act of receiving nourishment.
Alve'olar. [From the Lat. alveolus, a "little hollow."] Pertaining to the
alveoli, the cavities for the reception of the teeth.
Amoe'ba. [From the Gr. ameibo, to "change."] A single-celled, proto-
plasmic organism, which is constantly changing its form by protrusions
and withdrawals of its substance.
Amce'boid. Like an amoeba.
Amphiarthro'sis. [From the Gr. ampho, "both," and arthron, a "joint."]
A mixed articulation ; one which allows slight motion.
Anabol'ic. [From the Gr. anaballo, to "throw" or "build up."] Pertaining
to anabolism, the process by means of which simpler elements are built
up into move complex.
Ansesthe'sia. [From the Gr. a, an, "without," and aisthanomai, to "per-
ceive," to " feel."] A condition of insensibility.
247
248 GLOSSARY.
Anastomo'sis. [From the Gr. ana, " by," " through," and stoma, a " mouth."]
Communication of branches of vessels with one another.
Aor'ta. [Gr. aorte from ce.ro, to " raise up."] The great artery that rises up
from the left ventricle of the heart.
Aponeuro'sis. [From the Gr. apo, "from," and neuron, a "nerve."] A
fibrous membranous expansion of a tendon ; the nerves and tendons
were formerly thought to be identical structures, both appearing as
white cords.
Arach'noid. [From the Gr. arachne, a "spider," a " spider's web," and eidosj
" form " or " resemblance."] Resembling a web.
Are'olar. [From the Lat. areola, a " small space," dim. of area.] A term
applied to a connective tissue containing small spaces.
Ar'tery. [From the Gr. aer, "air," and tereo, to "keep."] Literally, an
air-keeper (it being formerly believed that the arteries contained air.)
A tube which conveys blood from the heart to all parts of the body.
Arthro'dia. [From the Gr. arthron, a " joint."] A movable joint.
Artic'ular. Pertaining to an articulation or joint.
Asphyx'ia. [From the Gr. a, " without," and sphyxis, the " pulse."] Liter-
ally, without pulse. Condition caused by non-oxyge nation of the
blood.
At'rophy. [From the Gr. a, " without," and trophe, " nourishment."] Wast-
ing of a part from lack of nutrition.
Aud'itory. [From the Lat. audio, auditum, to "hear."] Pertaining to the
sense or organ of hearing.
Aur'icle. [From the dim. of Lat. auris, the "ear."] A little ear, a term
applied to the ear-shaped cavities of the heart.
Auric'ulo-ventric'ular. Pertaining to the auricles and ventricles of the heart.
Az'ygos. [From the Gr. a, " without," and zygos, a " yoke."] Without a
feUow.
Bi'ceps. [From the Lat. bis, " twice," and caput, the " head."] A term
applied to muscles having a double origin or two heads.
Bicus'pid. [From the Lat. bis, " twice," and cuspis, the " point of a spear."]
Having two points.
Brach'ial. [From the Lat. brachium, the " arm."] Belonging to the arm.
Buc'cal. [From the Lat. bucca, the "cheek."] Pertaining to the cheek;
the mouth cavity formed chiefly by the cheeks.
Bur'sal. [From the Gr. bursa, a " bag."] Pertaining to bursce, membranous
sacs.
Ca'cum. [From the Lat. ccecus, " blind."] The blind gut.
Ca'lices, pi. of Ca'lyx. [From the Gr. kalyx, a " cup."] Anatomists have
given this name to small cup-like membranous canals, which surround
the papillse of the kidney, and open into its pelvis.
Canalic'ulus, pi. Canalic'uli. [Dim. of Lat. canalis, a "channel."] A small
channel or vessel.
Cancellated. [From the Lat. cancelli, "lattice-work."] A term used to
describe the spongy lattice-work texture of bone.
GLOSSARY. 249
Canthus. [Gr. Kanthos, the " angle of the eye."] The angle formed by the
junction of the eyelids, the internal being the greater, the external the
lesser, canthus.
Cap'illary. [From the Lat. capillus, "hair."] A minutely fine vessel,
resembling a hair in size.
Car'bon. An elementary body, one of the principal elements of organized
bodies.
Carbon'ic Acid, C02. An acid gaseous product.
Carot'ids. [Perhaps from the Gr. karos, " stupor," because pressing on them
produces stupor.] The great arteries conveying blood to the head.
Ca'sein. [From the Lat. caseus, "cheese."] The albumin of milk; the
curd separated from milk by the addition of rennet, constituting the
basis of cheese.
Caud'a Equi'na. [Lat.] " Horse-tail." A term applied to the termination
of the spinal cord, which gives off a large number of nerves which, when
unravelled, resemble a horse's tail.
Cell'ulose. Basis of vegetable fibre.
Cerebellum. [Dim. of Lat. cerebrum, the " brain."] The hinder and lower
part of the brain ; the little brain.
Cer'ebrum. [Lat. the "brain."] Chief portion of brain.
Ceru'minous. [From the Lat. cerumen, " ear-wax."] A term applied to the
glands secreting cerumen, ear-wax.
Chon'drin. [From the Gr. chondros, "cartilage."] A kind of gelatin
obtained by boiling cartilage.
Chor'dae Tendin'eae. [Lat.] Tendinous cords.
Cho'roid. [From the Gr. chorion, " skin," and eidos, " form " or " resem-
blance."] A skin-like membrane : the second coat of the eye.
Chyle. [From the Gr. kylos, " juice."] Milky fluid of intestinal digestion.
Chyme. [From the Gr. kymos, "juice."] Food that has undergone gastric
but not intestinal digestion. (Both chyle and chyme signify literally
liquid or juice.)
Cica'trix. [Lat. a " scar."] The mark or scar left after the healing of a
wound.
Cil'ia. [Lat. the " eyelashes."] Hair-like processes of certain cells.
Cil'iary. Pertaining to the cilia.
Cil'iated. Provided with cilia.
Circumval'late. [From the Lat. circumvallo, "to surround with a wall."]
Surrounded by a wall.
Clav'icle. [From the dim. of Lat. clavis, a " key."] The collar-bone, so
named from its shape.
Coc'cyx. [Lat. the "cuckoo."] The lower curved bone of the spine,
resembling a cuckoo's bill in shape.
Cocb/lea. [Lat. a "snail," a "snail-shell"; hence, anything spiral.] A
term applied to a cavity of the internal ear.
Cce'liac. [From the Gr. koilos, "hollow."] Pertaining to the abdominal
cavity.
Co'lon. [Gr. kolonJ] That portion of the large intestine which extends
from the caecum to the rectum.
250 GLOSSARY.
Colos'trum. First milk secreted after labour.
Colum'nae Car'neae. [Lat.] "Fleshy columns"; muscular projections in the
ventricles of the heart.
Colum'nar. Formed in columns: having the form of a column.
Com'missure. [From the Lat. con, " together," and mitto, missum, to " put."]
A joining or uniting together. Something which joins together.
Con'cha. [Lat. a "shell."] A term applied to the hollow portion of the
external ear.
Con'dyle. [From the Gr. kondylos, a "knob," or "knuckle."] An articu-
lar eminence.
Conjunct!' va. [From the Lat. con, " together," and jungo,junctum, to " join."]
A term applied to the delicate mucous membrane which lines both eye-
lids and covers the external portion of the eyeball.
Co'rium. [Lat. the "skin."] The deep layer of the skin ; the derma.
Cor'nea. [From the Lat. cornu, a " horn."] The transparent anterior portion
of the eyeball.
Coro'nal. [From the Lat. corona, a " crown."] Pertaining to the crown.
Cor'onary. [From the Lat. corona, a " crown."] A term applied to vessels,
ligaments, and nerves Y^hich encircle parts like a crown, as the coronary
arteries of the heart.
Cor'pus Callo'sum. [Lat.] " Callous body," or substance. A name given to
the hard substance uniting the cerebral hemispheres.
Cor'puscle. [From the dim. of Lat. corpus, a " body."] A small body or
particle.
Cor'tex. [Lat. " bark."] External layer of kidney : external layer of brain.
Cos'tal. [From the Lat. costa, a "rib."] Pertaining to the ribs.
Cra'nium. [Lat.] The skull.
Crassamen'tum. [From the Lat. crassus, "thick."] The thick deposit of
any fluid, particularly applied to a clot of blood.
Crena'ted. [From the Lat. crena, a " notch."] Notched on the edge.
Crib'riform. [From the Lat. cribrum, a " sieve," and/orma, "form."] Perfo-
rated like a sieve.
Cru'ra Cer'ebri. [From the Lat. crus (pi. crura), a "leg."] Legs or pillars
of the cerebrum.
Cry'pt. [From the Gr. krypto, to "hide."] A secreting cavity: a follicle
or glandular cavity.
Cu'ticle. [From the dim. of Lat. cutis, the "skin."] A term applied to the
upper or epidermal layer of the skin.
Cu'tis Ve'ra. [Lat.] The true skin ; that underneath the epidermal layer.
Cys'tic. [From the Gr. kystis, the "bladder."] Pertaining to a cyst, — *
bladder or sac.
Decussa'tion. [From the Lat, decusso, decussatum, to "cross."] The cross-
ing or running of one portion athwart another.
Del'toid. Having a triangular shape ; resembling the Greek letter A (delta}.
)ex'trm. A soluble substance obtained from starch.
Diabe'tes Mel'litus. [From the Gr. dia, "through," baino, "to go," and
meh, " honey."] Excessive flow of sugar-containing urine.
GLOSSARY. 251
Dial'ysis. [From the Gr. dialyo, to " dissolve."] Separation of liquids by
membranes.
Diapede'sis. [From the Gr. dia, " through," and pedao, to " leap," to " go."]
Passing of the blood-corpuscles through vessel walls without rupture:
sweating of blood.
Di'aphragm. [From the Gr. diaphrasso, to "divide in the middle by a parti-
tion."] The partition muscle dividing the cavity of the chest from that
of the abdomen.
Diarthro'sis. [From the Gr. dia, " through," as implying no impediment,
and arthron, a "joint."] A freely movable articulation.
Dias'tole. [From the Gr. diastello, to "dilate."] The dilation of the heart.
Dip'loe. [From the Gr. diploo, to "double," to "fold."] The osseous tissue
between the tables of the skull.
Dis'cus Prolig'erous, or germ disk. A term applied to a mass of cell cling-
ing to the ovum when it is set free from the ovary.
Dis'tal. [From the Lat. dis, " apart," and sto, to " stand."] Away from the
centre.
Dor' sal. [From the Lat. dorsum, the "back."] Pertaining to the back or
posterior part of an organ.
Duc'tus Arterio'sus. [Lat.] Arterial duct.
Duc'tus Veno'sus. [Lat.] Venous duct.
Duode'num. [From the Lat. duodeni, "twelve each."] First part of small
intestines, so called because about twelve fingers' breadth in length.
Du'ra Ma'ter. [Lat.] The "hard mother," called dura because of its great
resistance, and mater because it was formerly believed to give rise to
every membrane of the body. The outer membrane of the brain and
spinal cord.
Dyspnce'a. [From the Gr. dys, "difficult," and pneo, to "breathe."] -Diffi-
cult breathing.
Efferent. [From the Lat. effero, to " carry out."] Bearing or carrying out-
wards, as from the centre to the periphery.
Elimination. [From the Lat. e, " out of," and limen, liminis, a "threshold."]
The act of expelling waste matters. Eliminate signifies, literally, to
throw out of doors.
Em'bryo. The ovum and product of conception up to the fourth month,
when it becomes known as the foetus.
Enarthro'sis. [From the Gr. en, "in," and arthron, a "joint."] An articu-
lation in which the head of one bone is received into the cavity of
another, and can be moved in all directions.
Endocardium. [From the Gr. endon, "within, "and kardia, the "heart."]
The lining membrane of the heart.
En'dolymph. [From the Gr. endon, "within," and Lat. lympha, "water."]
The fluid in the membranous labyrinth of the ear.
En'siform. [From the Lat. ensis, a "sword," and forma, "form."] Shaped
like a sword.
Ep'iblast. [From the Gr. epi, "upon," and blastos, a "germ," or "sprout."]
The external or upper layer of the germinal membrane.
252 GLOSSARY.
Epidermis. [From the Gr. epi, " upon," and derma, the " skin."] The outer
layer of the skin.
Epiglot'tis. [From the Gr. epi, " upon," and glottis, the " glottis."] The car-
tilage at the root of the tongue which forms a lid or cover for the aper-
ture of the larynx.
Epithelial. [From the Gr. epi, " upon," and thele, the " nipple."] Pertain-
ing to the epithelium, the cuticle covering the nipple, or any mucous
membrane. The term epithelium is now applied to the tissue composed
of cells covering or lining all surfaces of the body.
Eth'moid. [From the Gr. ethmos, a "sieve," and eidos, "form," "resem-
blance."] Sieve-like. A bone of the cranium, part of which is pierced
by a number of holes.
Eusta'chian Tube. A tube extending from behind the soft palate to the
drum of the ear, first described by EustacMus.
Fallo'pian. A term applied to tubes and ligaments first pointed out by the
anatomist Fallopius.
Fas'cia, pi. Fas'cise. [Lat.] A bandage, — that which binds ; a membranous
fibrous covering.
Fau'ces. [Lat., pi. of faux, faucis, the "throat."] The cavity at the back of
the mouth from which the larynx and pharynx proceed.
Fem'oral. Pertaining to the femur.
Fe'mur. [Lat.] The thigh.
Fenes'tra. [Lat.] A window.
Fibrilla, pi. Fibrillae. [Dim. of Lat. fibra, a "fibre."] A little fibre.
Fibrin'ogen. A proteid in blood plasma, main constituent of fibrin.
Fib'ula. [Lat. a " clasp."] The long splinter bone of the leg.
Filiform. [From the Lat. filum, a "thread," and forma, "form."] Thread-
like.
Fim'briae. [Lat. "threads," a "fringe."] A border or fringe.
Fim'briated. Fringed.
Fis'sion. [From the Lat. findo, fissum, to " cleave."] A cleaving or break-
ing up into two parts.
Foe'tus. The child in utero from the fifth month of pregnancy till birth.
Follicle. [From the dim. of Lat. follis, a "bag."] A little bag; a small
gland.
Fontanelle'. [Fr.] A little fountain. A term applied to the membranous
spaces between the cranial bones in the new-born infant, in which the
pulsation of the blood in the cranial arteries was imagined to rise and
fall like the water in a fountain.
Fora'men, pi. Foramina. [Lat.] An opening, hole, or aperture.
Foramen Mag'num. [Lat.] A large opening.
Fora'men Ovale. [Lat.] An oval opening.
Fos'sa, pi. Fos'sae. [From the Lat. fodio, fossum, to "dig."] A depression
or sinus ; literally, a ditch.
Fo'vea Centralis. [Lat.] Central depression.
Fun'dus. [Lat.] The base or bottom of any organ which has an external
opening.
GLOSSARY. 253
Fun'giform. [From the Lat. fungus, a " mushroom," and forma, "form."]
Having the shape of a mushroom.
Funic'ulus. [Dim. of Lat. funis, a " rope."] A little cord, or bundle of
aggregated fibres.
Fu'siform. [From the Lat. fusus, a "spindle," said forma, "form."] Spin-
dle-shaped.
Gang'lia, pi. of Ganglion. [From the Gr. gagglion, a "knot."] A knot-like
arrangement of nervous matter in the course of a nerve.
Gas'tric. [From the Gr. gaster, the " stomach."] Pertaining to the stomach.
Gastrocne'mius. [From the Gr. gaster, the " belly," and kneme, the " leg."]
The 6e%-shaped muscle of the leg.
Genioglos'sus. [From the Gr. geneion, the " chin," and glossa, the " tongue."]
A muscle connected with the chin and tongue.
Ginglymus. [From the Gr. gigglymos, a "hinge."] A forage-joint.
Gladi'olus. [Dim. of Lat. gladius, a "sword."] The middle piece of the
sternum.
Glair'y. [From the Lat. clarus, " clear " ; Fr. clair.~] Like the clear white
part of an egg.
Gle'noid. [From the Gr. glene, a "cavity," and eidos, "form," "resem-
blance."] A name given to a shallow cavity.
Glomer'ulus. [Dim. of Lat. glomus, a "clue of thread," or "ball."] A
botanical term signifying a small, dense, roundish cluster : a term
applied to the &a//-like tuft of vessels in capsules of the kidneys.
Glos'so-pharynge'al. [From the Gr. glossa, the " tongue," and pharygx, the
" pharynx."] Belonging to the tongue and pharynx.
Glot'tis. [Gr. the " mouthpiece of a flute."] The aperture of the larynx.
Glute'i, pi. of Glute'us. [From the Greek gloutoi, the " buttocks."] The
muscles forming the buttocks.
Gly'cogen. Literally, producing glucose. Animal starch found in liver,
which may be changed into glucose.
Graaf ian Follicles, or Vesicles. A term applied to the hollow bodies in the
ovaries, containing the ova.
Gramme. Unit of metric system, 15.43 grains troy.
Gus'tatory. [From the Lat. gusto, gustatum, to " taste."] Belonging to the
sense of taste.
Haemoglo'bin. [From the Gr. haima, " blood," and Lat. globus, a " globe,"
or " globule."] A complex substance which forms the principal part of
the blood-globules, or red corpuscles of the blood.
Haemorrhoi'dal. [From the Gr. haima, " blood," and rheo, to " flow."] Per-
taining to haemorrhoids, small tumours of the rectum, which frequently
Need.
Haver'sian Canals. Canals in the bone, so called from their discoverer, Dr.
Clopton Havers.
Hepatic. [From the Gr. hepar, hepatos, the " liver."] Pertaining to the liver.
Hilum, sometimes written Hilus. [Lat.] A small fissure, notch, or depres-
sion. A term applied to the concave part of the kidney.
254 GLOSSARY.
Homoge'neous. [From the Gr. homos, "the same," and genos, "kind."] Of
the same kind or quality throughout ; uniform in nature, — the reverse
of heterogeneous.
Hu'merus. [Lat. the "shoulder."] The arm-bone which concurs in form-
ing the shoulder.
Hy'aline. [From the Gr. hyalos, "glass."] Glass-like, resembling glass in
transparency.
Hy'drogen. An elementary gaseous substance, which in combination with
oxygen produces water, H2O.
Hy'oid. [From the Gr. letter v, and eidos, " form," " resemblance."] The
bone at the root of the tongue, shaped like the Greek letter v.
Hypermetro'pia. [From the Gr. hyper, " over," " beyond," metron, " measure,"
and ops, the " eye."] Far-sightedness.
Hyper'trophy. [From the Gr. hyper, " over," and trophe, " nourishment."]
Excessive growth ; thickening or enlargement of any part or organ.
Hy'poblast. [From the Gr. hypo, "under," and blastos, a "sprout" or
" germ."] The internal or under layer of the germinal membrane.
Hypochon'driac. [From the Gr. hypo, " under," and chondros, a " carti-
lage."] A term applied to the region of abdomen under the cartilages
of the false ribs.
Hypoglos'sal. [From the Gr. hypo, " under, " and glossa, the " tongue."] A
name given to a nerve which terminates under the tongue.
Il'eum. [From the Gr. eiled, to " twist."] The longest twisting portion of
the small intestine.
Il'iac. Pertaining to the ileum.
Il'ium, pi. Il'ia. [From the Gr. eiled, to " twist."] The upper part of the
os innominatum; the haunch-bone ; perhaps so called because the crest
of the bone turns or twists upon itself.
Infundib'ula. [Lat. pi. of infundibulum, a "funnel."] Funnel-shaped canals.
In'guinal. [From the Lat. inguen, inguinis, the "groin."] Pertaining to
the groin.
Inos'culate. [From the Lat. in, " into," and osculum, a " little mouth."] To
unite, to open into each other.
Insaliva'tion. The process of mixing the saliva with the food in the act of
mastication.
In'sulate. [From the Lat. insula, an "island."] To isolate or separate from
surroundings.
Intercellular. Lying between cells.
Interlob'ular. That which lies between the lobules of any organ.
Inter'stice. [From the Lat. inter, " between," and sto or sisto, to " stand."]
The space which stands between things ; any space or interval between
parts or organs.
Intersti'tial. Pertaining to or containing interstices.
Intralob'ular. That which lies within the lobules of any organ.
I'ris. [Lat. the "rainbow."] The coloured membrane suspended behind
the cornea of the eye. It receives its name from the variety of its
colours.
GLOSSARY. 255
Is'chium. [From the Gr. ischuo, to " support."] The lower portion of the
os innominatum; that upon which the body is supported in a sitting
posture.
Jeju'num. [From the Lat. jejunus, "fasting," "empty."] The part of the
small intestine comprised between the duodenum and ileum. It has
been so called because it is almost always found empty after death.
Ju'gular. [From the Lat. jugulum, the " throat."] Pertaining to the throat.
Katabol'ic. [From the Gr. kataballo, to "throw down."] Pertaining to
kalabolism, the process by means of which the more complex elements
are rendered more simple and less complex. The opposite of anabolism.
Lach'rymal. [From the Lat. lachryma, a " tear."] Belonging to the tears.
Lac'tation. [From the Lat. lac, lactis, "milk."] The period of giving milk.
Lac'teal. A term applied to the lymphatic vessels in the intestines which
absorb the milk-like fluid, the chyle, from the intestines.
Lac'tic Acid. An acid obtained from sour milk.
Lacu'na, pi. Lacu'nse. [Lat. a "cavity," an "opening."] A little hollow
space.
Lambdoi'dal. [From the Gr. letter A (Lambda"), and eidos, "form," "resem-
blance."] Resembling the Gr. letter A.
Lamella, pi. Lamel'lae. [Lat.] A thin plate or layer.
Lar'ynx. The upper part of the air passage, between the trachea and the
base of the tongue.
Latis'simus Dor'si. [Lat. superlative of latus, "broad," "wide," and dorsum,
the "back."] The ividest muscle of the back.
Lec'ithin. [From the Gr. lekithos, the " yellow of egg."] A complex, fatty
substance found in the brain ; in the yolk of eggs.
Leu'cocyte. [From the Gr. leukos, "white," and kytos, a "cell."] A term
used to denote the white or pale corpuscles in the blood and lymph.
Lig'ament. [From the Lat. ligo, ligatum, to "bind."] Anything that binds
or unites.
Lin'ea Alba. [Lat.] The white line formed by the crossing of the apon-
eurotic fibres in the middle line of the abdomen.
Lin'ea Ilio-pectine'a. [Lat.] A line forming the brim of the pelvis, so
named from subjacent bone and muscle.
Lob'ule. [From the dim. of Lat. lobus, a " lobe."] A small lobe.
Lum'bar. [From the Lat. lumbus, the "loin."] Pertaining to the loins.
Lymph. [From the Lat. lympha, "water."] A colourless fluid, resembling
water in appearance.
Lymphat'ic. Pertaining to lymph ; a vessel or tube containing lyrnph.
Lymphoid. [From the Lat. lympha, "water," and Gr. eidos, "form," "re-
semblance."] Having resemblance to lymph.
Mac'ula Lute'a. [Lat.] Yellow spot.
Ma'lar. [From the Lat. mala, the "cheek."] Pertaining to the cheek.
Malle'olus, pi. Malle'oli. [Dim. of Lat. malleus, a "hammer."] A name
given to the pointed projections formed by the bones of the leg at the
ankle-joint.
256 GLOSSARY.
Malpig'hian Bod'ies. [So called in honour of Malpighi, a celebrated Italian
anatomist.] A term applied to small bodies or corpuscles found in the
kidney and spleen.
Manu'brium. [Lat. a " haft," a " handle."] Name given to the upper por-
tion of the breast bone.
Mar'garin. One of the three chief constituents of fat.
Mas'seter. [From the Gr. massaomai, to " chew."] One of the muscles of
mastication.
Mas'toid. [From the Gr. mastos, the "breast," and eidos, "form," "resem-
blance."] Shaped like the breast.
Ma'trix. [Lat.] The womb. Producing or containing substance.
Max'illary. [From the Lat. maxilla, a "jaw."] Pertaining to the maxillce
or jaws.
Mea'tus. [From the Lat. meo, meatum, to "pass."] A passage or
canal.
Medul'la Oblonga'ta. [Lat.] The " oblong marrow " ; that portion of the
brain which lies within the skull, upon the basilar process of the occip-
ital bone.
Meibo'mian. A term applied to the small glands between the conjunctiva
and tarsal cartilages, discovered by Meibomius.
Mes'entery. [From the Gr. mesos, "middle," and enteron, the "intestine."]
A duplicature of the peritoneum covering the small intestine, which
occupies the middle or centre of abdominal cavity.
Mes'oblast. [From the Gr. mesos, " middle," and blastos, a " germ " or
" sprout."] The middle layer of the germinal membrane.
Mesoco'lon. A duplicature of the peritoneum covering the colon.
Metab'olism. [From the Gr. metabole, "change."] The changes taking
place in cells, whereby they become more complex and contain more
force, or less complex and contain less force. The former is constructive
metabolism, or anabolism ; the latter, destructive metabolism, or katab-
olism.
Metacar'pus. [From the Gr. meta, "after," and karpos, the "wrist."] The
part of the hand comprised between the wrist and fingers.
Metatar'sus. [From the Gr. meta, " after," and tarsos, the " instep."] That
part of the foot comprised between the instep and toes.
Mi'tral. Resembling a mitre.
Mo'lar. [From the Lat. mola, a " mill."] A term applied to the teeth which
bruise or grind the food.
Molec'ular. Pertaining to molecules.
Mol'ecule. [From the dim. of Lat. moles, a " mass."] The smallest quantity
into which the mass of any substance can physically be divided. A
molecule may be chemically separated into two or more atoms.
Mo'tor Oc'uli. [Lat.] Mover of the eye.
Moto'rial. That which causes movement.
Mu'cin. The chief constituent of mucus.
Mu'cous. A term applied to those tissues that secrete mucus.
Myocar'dium. [From the Gr. mys, myos, a " muscle," and kardia, the " heart."]
The muscular structure of the heart.
GLOSSARY. 257
Myo'pia. [From the Gr. myo, to " contract," and ops, the " eye."] Near-
sightedness.
My'osin. Chief proteid substance of muscle.
Na'ris, pi. Na'res. [Lat.] A nostril.
Weurilem'ma. [From the Gr. neuron, a "nerve," and lemma, a "coat" or
" covering."] Nerve-sheath.
Ni'trogen. A colourless gas forming nearly four-fifths of the atmosphere :
the diluent of the oxygen in the air. Literally, that which generates
nitre.
Nucle'olus, pi. Nucle'oli. [Dim. of Lat. nucleus, a "kernel."] A smaller
nucleus within the nucleus.
Nu'cleus, pi. Nu'clei. [Lat. a "kernel."] A minute vesicle embedded in
the cell protoplasm.
Occipi'tal. [From the Lat. occiput, occipitis, the "back of the head."] Per-
taining to the occiput, the back part of the head.
Odon'toid. [From the Gr. odons, odontos, a "tooth," and eidos, "form,"
"resemblance."] Tooth-like.
(Ede'ma. [From the Gr. oideo, to "swell."] A swelling from effusion of
serous fluid into the areolar tissue.
(Esoph'agus. [Gr. oisophagos, from oio, (f ut.) oiso, to " carry," and phagema,
" food."] The gullet.
Olec'ranon. [From the Gr. olene, the "elbow," and kranon, the "head."]
The head of the elbow.
O'lein. [From the Lat. oleum, " oil."] One of the three chief constituents
of fat. Oil (oleum) signifies literally, juice of the olive (Lat. olea).
Olfac'tory. [From the Lat. olfacio, olfactum, to "smell."] Belonging to the
sense of smell.
Omen'tum. [Lat. "entrails."] A duplicature of the peritoneum with more
or less fat interposed.
Ophthal'mic. [From the Gr. ophthalmos, the " eye."] Belonging to the eye.
Op'tic. [From the Gr. opfo, to "see."] That which relates to sight.
O'ra Serra'ta. [Lat.] Serrated border.
Orbicula'ris. [From dim. of Lat. orbis, an " orb " or " circle."] Name of the
circular muscles.
Or'bital. [From the Lat. orbita, a "track," "rut of a wheel."] Pertaining
to the orbit, the bony cavity in which the eyeball is suspended.
Os, pi. O'ra. [Lat.] A mouth.
Os, pi. Ossa. [Lat.] A bone.
Osmo'sis. [From the Gr. osmos, " impulsion."] Diffusion of liquids through
membranes.
Os'sa Innomina'ta, pi. of Os Innomina'tum. [Lat.] " Unnamed bones."
The irregular bones of the pelvis, unnamed on account of their non-re-
semblance to any known object.
Os'teoblasts. [From the Gr. osteon, a " bone," and blastos, a " germ " or
" sprout."] The germinal cells deposited in the development of bone.
O'vum, pi. O'va. [Lat. an " egg."] The human germ cell.
258 GLOSSARY.
Oxida'tion. The action of oxidizing a body; that is, combining it with oxy-
gen, the result of which combination is an oxide.
Ox'ygen. A tasteless, odourless, colourless gas, forming part of the air,
water, etc., and supporting life and combustion.
Pal'mitm. A solid, crystallizable substance of fat, found in the nervous tissue.
Pal'pebra, pi. Pal'pebrae. [Lat.] The eyelid.
Pan'creas. A compound secreting gland ; one of the accessory organs of
nutrition. The sweetbread of animals.
Papil'lae. [Lat. pi. of papilla, a " nipple," a " pimple."] Minute eminences
on various surfaces of the body.
Paraglob'ulin. A proteid substance of the blood plasma.
Pari'etal. [From the Lat. paries, parietis, a " wall."] Pertaining to a wall.
Parot'id. [From the Gr. para, "near," and ous, otos, the "ear."] The large
salivary gland under the ear.
Parturi'tion. [From the Lat. par/urio, parturitum, to " bring forth."] The
act of bringing forth, of giving birth to young.
Par Va'gum. [Lat.] The " wandering pair." A term sometimes applied
to the pneumogastric nerves.
Patel'la. [Lat. "a little dish."] A small, fowl-shaped bone ; the knee-pan.
Pec'toral. [From the Lat. pectus, pectoris, the "breast."] Pertaining to the
breast or chest.
Ped'icle. [From the dim. of Lat. pes, pedis, a "foot."] A stalk.
Pel'vic. [From the Lat. pelvis, a " basin."] Pertaining to the pelois, the
basin or bony cavity forming the lower part of the abdomen.
Pep'sin. [From the Gr. pepfo, to " digest."] A ferment principle in gastric
juice, having power to convert proteids into peptones.
Pep'tone. [From the Gr. pepto, to " digest."] A term applied to proteid
material digested by the action of the digestive juices.
Pericar'dium. [From the Gr. peri, "about," "around," and kardia, the
" heart."] The serous membrane covering the heart.
Perichon'drium. [From the Gr. peri, "about," "around," and chondros, a
" cartilage."] The serous membrane covering the cartilages.
Per'ilymph. [From the Gr. peri, "about," " around," and the Lat. lympha,
" water."] The fluid in the osseous, and surrounding the membranous,
labyrinth of the ear.
Perios'teum. [From the Gr. peri, "about," " around," and osteon, a " bone."]
The membrane covering the bones.
Peripheral. [From the Gr. peri, " about," " around," and phero, to " bear."]
Pertaining to the periphery or circumference; that which is away from
t.hfi centre and towards the circumference.
Peristal'sis. [From the Gr. peristelld, to "surround," to "compress."]
Peristaltic action. A term applied to the peculiar movement of the
intestines, like that of a worm in its progress, by which they gradually
propel their contents.
Peritone'um. [From the Gr. periteino, to "stretch around," to "stretch all
over."] The serous membrane lining the walls and covering the con-
tents of the abdomen.
GLOSSARY. 259
Perone'al. [From the Gr. perone, the " fibula."] Pertaining to the fibula ;
a term applied to muscles or vessels in relation to the fibula.
Pe'trous. [From the Gr. petra, a " rock."] Having the hardness of rock.
Pey'er's Glands. The clustered glands in the intestines, so named after the
anatomist, Peyer, who well described them.
Phalan'ges. [Lat. pi. of phalanx, a "closely-serried array of soldiers."] A
name given to the small bones forming the fingers and toes, because
placed alongside one another like a phalanx.
Phar'ynx. [ From the Gr. pharao, to " plough," to " cleave."] The cleft or
cavity forming the upper part of the gullet.
Phren'ic. [From the Gr. phren, the "diaphragm."] Pertaining to the dia-
phragm.
Pi'a Ma'ter. [Lat. pia (fern.), "tender," "delicate," and mater, "mother."]
The most internal of the three membranes of the brain. See Dura
Mater.
Pig'ment. [From the Lat. pigmentum, " paint," " colour."] Colouring matter.
Pin'na. [Lat. a "feather" or "wing."] External cartilaginous flap of the
ear.
Placen'ta. [Lat. a " thin, flat cake."] A fiat, circular, vascular substance
which forms the organ of nutrition for the foetus in utero.
Plan'tar. [From the Lat. planta, the "sole of the foot."] Pertaining to the
sole of the foot.
Plas'ma. [From the Gr. plasso, " to form."] A tenacious plastic fluid, form-
ing the coagulating portion of the blood; that in which the blood-cor-
puscles float; the liquor sanguinis.
Pleu'ra. [Gr. the "side."] A serous membrane divided into two portions,
lining the right and left cavities of the chest, and reflected over each Inng.
Plex'us. [From the L&t.plecto, plexum, to " knit " or " weave."] A network
of nerves or veins.
Pneumogas'tric. [From the Gr. pneumdn, a "lung," and gaster, the "stom-
ach."] Pertaining to the lungs and stomach.
Polyhe'dral. [From the Gr. polys, "many," and hedra, a " base," a " side."]
Many-sided.
Pons Varo'lii. [Lat.] "Bridge of Varolius." The white fibres which form
a bridge connecting the different parts of the brain, first described by
Varolius.
Poplite'al. [From the Lat. poples, poplitis, the " ham," the "back part of the
knee."] The space behind the knee-joint is called the popliteal space.
Prismat'ic. Resembling a prism, which, in optics, is a solid, glass, triangu-
lar-shaped body.
Prona'tion. [From the Lat. pronus, "inclined forwards."] The turning of
the hand with the palm downwards.
Prona'tor. The group of muscles which turn the hand palm downwards.
Pro'teids. A general term for the albuminoid constituents of the body.
Pro'toplasm. [From the Gr. prdtos, " first," and plasxo, to " form."] Afirst-
formed organized substance ; primitive organic cell matter.
Pseudostom'ata. [From the Gr. pseudes, "false," and sloma, stomatos, a
" mouth."] False openings.
260 GLOSSARY
Pter'ygoid. [From the Gr. pteron, a " wing," and eidos, " form," " resem-
blance."] Wing-like.
Pty'alin. [From the Gr. pti/alon, "saliva."] A ferment principle in saliva,
having power to convert starch into sugar.
Pu'bes, gen. Pu'bis. [Lat.] The external part of the generative region;
the portion of the os innominatum forming the front of the pelvis.
Pul'monary. [From the Lat. pulmo, pi. pulmones, the " lungs."] Relating
to the lungs.
Pylor'ic. Pertaining to the pylorus.
Pylor'us. [From the Gr. pyle, a "gate" or "entrance," and ouros, a
" guard."] The lower orifice of the stomach, furnished with a circular
valve which closes during stomach digestion.
Pyrex'ia. [From the Gr. pyresso, (fut.) pyrexo, to "have a fever."] Eleva-
tion of temperature; fever.
Quad'riceps. [From the Lat. quatuor, " four," and caput, the " head."] A
term applied to the extensor muscle of the leg, having four heads or
parts.
Ra'dius. [Lat. a " rod," the " spoke of a wheel."] The outer bone of the
fore-arm, so called from its shape.
Rale. [From the Fr. rdler, to "rattle in the throat."] A rattling, bubbling
sound attending the circulation of air in the lungs. Different from the
murmur produced in health.
Rec'tus. [Lat.] Straight.
Re'nal. [From the Lat. ren, renis, the "kidney."] Pertaining to the kidneys.
Retic'ular. [From the Lat. reticulum, a " small net."] Resembling a small
net.
Ret'iform. [From the Lat. rete, a " net," and forma, " form."] Having the
form or structure of a net.
Ret'ina. [From the Lat. rete, a " net."] The most internal membrane of
the eye; the expansion of the optic nerve.
Ri'ma Glot'tidis. [Lat. rima, a "chink" or "cleft."] The opening of the
glottis.
Ru'gae. [Lat. pi. of ruga, a "wrinkle."] A term applied to the folds or
wrinkles in the mucous membrane, especially of the stomach and vagina.
Sa'crum. [Lat. neut. of sacer, "sacred."] The large triangular bone above
the coccyx, so named because it was supposed to protect the organs con-
tained in the pelvis, which were offered in sacrifice and considered
sacred.
Sag'ittal. [From the Lat. sagitta, an " arrow."] Arrow-shaped.
Sal'ivary. Pertaining to the saliva, the fluid secreted by the glands of the
mouth.
Saphe'nous. [From the Gr. saphes, " manifest."] A name given to the two
large superficial veins of the lower limbs.
Saponifica'tion. [From the Lat. sapo, saponis, "soap," and facio, to
" make."] Conversion into soap.
GLOSSARY. 261
Sarcolem'ma. [From the Gr. sarx, sarkos, "flesh," and lemma, a "cover-
ing."] The covering of the individual muscle fibrils.
Sar'cous. [From the Gr. sarx, sarkos, " flesh."] Fleshy, belonging to flesh.
Sarto'rius. [From the Lat. sartor, a "tailor."] The name of the muscle
used in crossing the legs, as a tailor does when he sits and sews.
Scap'ula. [Lat] The shoulder-blade.
Sclerot'ic. [Lat. scleroticus, from Gr. skleroo, to " harden."] Hard, tough.
Seba'ceous. A term applied to glands secreting sebum.
Se'bum or Se'vum. [Lat. sevum, "suet."] A fatty secretion resembling
suet, which lubricates the surface of the skin.
Semilu'nar. [From the Lat. semis, "half," and luna, the "moon."] Having
the shape of a half-moon.
Se'rous. Having the nature of serum.
Se'rum. [Lat.] The watery fluid separated from the blood after coagula-
tion.
Ses'amoid. [From the Gr. sesamon, a "seed of the sesamum," and eidos,
"form," "resemblance."] Resembling a grain of sesamum. A term
applied to the small bones situate in the substance of tendons, near
certain joints.
Sig'moid. [From the Gr. letter 5, sigma, and eidos, "form," "resemblance."]
Curved like the letter S.
Sole'us. [From the Lat. solea, a "sandal."] A name given to a muscle
shaped like the sole of a shoe.
Specific Grav'ity. The comparative density or gravity of one body con-
sidered in relation to another assumed as the standard. In measuring
the specific gravity of liquids or solids, water is usually taken as the
standard of comparison, being reckoned as a unit.
Sphe'noid. [From the Gr. sphen, a "wedge," and eidos, "form," "resem-
blance."] Like a wedge.
Sphinc'ter. [From the Gr. sphiggo, to "bind tight," to " close."] A circu-
lar muscle which contracts the aperture to which it is attached.
Squa'mous. [From the Lat. squama, a "scale."] Scale-like.
Sta'sis. [From the Gr. stad, to " stop."] Stagnation of the blood current.
Ste'arin. One of the three chief constituents of fat.
Ster'num. [Lat.] The breast-bone.
Stim'ulus, pi. Stim'uli. [Lat. a " goad."] Anything that excites to action.
Sto'ma, pi. Stom'ata. [From the Gr. stoma, stomatos, a "mouth."] A
mouth ; a small opening.
Strat'ified. [From the Lat. stratum, a "layer," and facio, to "make."]
Formed or composed of strata or layers.
Stri'ated. [From the Lat. strio, striatum, to " make furrows."] That which
has stria?, furrows or lines.
Stro'ma. [From the Gr. stroma, a " bed."] The foundation or led tissue of
an organ.
Styloglos'sus. [From the Gr. stylos, a "pillar," and glossa, the tongue."]
A muscle connected with a pointed style-like process of the temporal bone
and the tongue.
Subcla'vian. Under the clavicle.
262 GLOSSARY.
Subcuta'neous. [From the Lat. sub, " under," and cutis, the "skin."] Under
the skin.
Sudoriferous. [From the Lat. sudor, "sweat," and fero, to "carry," to
" bear."] A terra applied to the glands secreting sweat.
Supina'tion. [From the Lat. supino, supinatum, to " bend backwards," to
"place on tlie back."] The turning of the hand with the palm up-
ward, the posterior surface of the hand being supine.
Su'pinators. The muscles which turn the hand with the palm upward.
Suprare'nal. [From the Lat. super, "over," and ren, renis, the "kidney."]
Above the kidney.
Su'ture. [From the Lat. suo, sutum, to "sew together."] That which is
sewn together, a seam; the seam uniting bones of the skull.
Sym'physis. [From the Gr. syn, "together," and phyo, to "produce," to
"grow."] A union of bones, usually of symmetrical bones in the
median line, as the pubic bones and bones of the jaw.
Synarthro'sis. [From the Gr. syn, "together," and arthron, a "joint."] A
form of articulation in which the bones are immovably joined together.
Synchondro'sis. [From the Gr. syn, " together," and chondros, " cartilage."]
Union by an intervening growth of cartilage.
Syndesmo'sis. [From the Gr. syn, " together," and desmos, a " ligament."]
Union by ligaments.
Syno'via. [Supposed to be from the Gr. syn, " together," implying union
or close resemblance, and don, an "egg."] A fluid resembling the
white of an egg.
Syno'vial. Pertaining to synovia.
Syn'tonin. [From the Gr. synteino, to "stretch," to "draw," referring to
the peculiar property of muscular fibre.] A name given by Lehman n to
a substance obtained from muscular fibre by the action of dilute
muriatic acid.
Sys'tole. [From the Gr. systello, to "draw together," to "contract."] The
contraction of the heart.
Tar'sus. [From the Gr. tarsos, the "instep."] The instep: the cartilage of
the eyelid.
Ten'do Achil'lis. [Lat.] " Tendon of Achilles." The tendon attached to the
heel, so named because Achilles is supposed to have been held by the
heel when his mother dipped him in the river Styx to render him in-
vulnerable.
Thorac'ic. [From the Gr. thorax, a "breast-plate," the "breast."] Pertain-
ing to the thorax.
Thy'roid. [From the Gr. thyreos, an "oblong shield," and eidos, "form,"
"resemblance."] Resembling a shield. A name given to an opening in
the ossa innominata: to the piece of cartilage forming the anterior
prominence of the larynx: to the gland placed in front of the larynx.
Tib'ia. [Lat. a "flute" or "pipe."] The shin-bone, called tibia, f rom its
fancied resemblance to a reed-pipe.
Tibia'lis Anti'cus. [Lat.] The muscle situate at the anterior part of the
tibia.
GLOSSARY. 263
Tibia'lis Posti'cus. [Lat.] The muscle situate at the posterior part of the
tibia.
Tone. [Gr. tonos, from, teino, to "stretch."] The state of tension or firmness
proper to each organic tissue.
Trabec'ulae. [Lat. pi. of trabecula, a "little beam."] A term applied to
prolongations of fibrous membranes which form septa, or partitions.
Tra'chea. [Lat.] The windpipe.
Transversa'lis. [Lat. from trans, " across," and verto, versum, to "turn, "to
"direct."] A term applied to a muscle which runs in a transverse direc-
tion.
Trape'zius. A name given to the two upper superficial muscles of the back,
because together they resemble a trapezium, or diamond-shaped quad-
rangle.
Tri'ceps. [From the Lat. tres, " three," and caput, the "head."] A term
applied to a muscle having a triple origin, or three heads.
Tri'cuspid. [From the Lat. tres, "three," and cuspis, cutpidis, a "point."]
Having three points.
Trochan'ter. [From the Gr. trochao, to "turn," to "revolve."] Name given
to two projections on the upper extremities of the femur, which give
attachment to the rotator muscles of the thigh.
Tryp'sin. The ferment principle in pancreatic juice which converts proteid
material into peptones.
Tuberos'ity. [From the Lat. tuber, tuberis, a "swelling."] A protuberance.
Tur'binated. [Lat. turbinatu*, from turbo, turbinis, a "top."] Formed like a
top ; a name given to the bones in the outer wall of the nasal fossae.
Tym'panum. [From the Gr. tympanon, a " drum."] The drum or hollow
part of the middle ear.
Ul'na. [Lat. the "elbow."] The inner bone of the fore-arm, the olecranon
process of which forms the elbow.
Umbil'icus. [Lat. the "navel."] A round cicatrix or scar in the median
line of the abdomen.
U'rea. [From the Lat. urina, "urine."] Chief solid constituent of urine.
Nitrogenous product ot tissue decomposition.
Ure'ter. [From the Gr. oureo, to "pass urine."] The tube through which
the urine is conveyed from the kidney to tlie bladder.
Ureth'ra. [From the Gr. oureo, to "pass urine."] The canal through which
the urine is conveyed from the bladder to the meatus urinarins.
U'vula. [Dim. of Lat. vva, a "grape."] The small, elongated, fleshy body
hanging from the soft palate.
Vag'inal. [From the Lat. vagina, a " sheath."] Sheath-Yike.
Val'vulae Conniven'tes. [Lat.] A name given to transverse folds of the
mucous membrane in the small intestine.
Vas'a Vaso'rum. [Lat.] "The vessels of the vessels." The small blood-
vessels which supply the walls of the larger blood-yesxe/s with blood.
Vas'cular. [From the Lat. vasculum, a "little vessel."] Relating to vessels;
full of vessels.
264 GLOSSARY.
Vaso-mo'tor. [From the Lat. vas, a " vessel," and moveo, motum, to " move."]
Causing motion to the vessels. Vaso-motor nerves cause contraction and
relaxation of the blood-vessels.
Ve'nae Ca'vae, pi. of Ve'na Ca'va. [Lat.] " Hollow veins." A name given
to the two great veins of the body which meet at the right auricle of the
heart.
Ve'nae Com'ites. [Lat.] " Attendant veins." Veins which accompany the
arteries.
Ven'tral. [From the Lat. venter, ventris, the "belly."] Belonging to the
belly cavity.
Ven'tricle. [From the dim. of Lat. venter, the "belly."] A small cavity.
Ver'miform. [From the Lat. vermis, a " worm," &ud forma, " form."] Worm-
shaped.
Ver'nix Caseo'sa. [Lat.] " Cheesy varnish." The fatty varnish found on
the new-born infant, which is secreted by the sebaceous glands of the
skin.
Ver'tebrae, pi. of Ver'tebra. [Lat. from verto, to " turn."] The bones of the
spine.
Vil'li. [Lat. pi. of villus, "shaggy hair."] The conical projections on the
valvulae conniventes, making the mucous membrane look shaggy.
Vis'cera. [Lat.] The internal organs of the body.
Vitel'line. [From the Lat. vitellus, the "yolk of an egg."] A term applied
to the yolk membrane.
Vetl'lus. [Lat. from vita, "life."] The yolk of an egg.
Vit'reous. [From the Lat. vitrum, " glass."] Glass-like. A name applied to
the transparent, jelly-like substance which fills the back part of the eye-
ball behind the crystalline lens.
Vo'mer. [Lat. a "ploughshare."] The thin plate of bone shaped some-
what like a, ploughshare which separates the nostrils.
Vul'va. The external female genitals.
Zo'na Pellu'cida. [Lat.] "Pellucid zone." The broad, transparent ring
which surrounds the yolk in the centre of the ovum.
INDEX.
Abdomen, divisions of, 154.
Absorbents, 119.
Absorption, 175.
Adipose tissue, 17.
Adjustment of the eye, how accom-
plished, 233.
Air-sacs, 133.
Albumin, 78.
Alimentary canal, 153.
Amoeboid movement, 77.
Aorta, 94.
abdominal, 98.
thoracic, 98.
Aponeuroses, 16.
Appendix vermiform, 162.
Aqueous humour of eye, 232.
Arachnoid membrane, 204.
Areolar tissue, 14.
Arterial tension, 111.
Arteries, of head and neck, 96.
of lower limb, 101.
structure of, 88.
table of, 107.
of upper limb, 97.
Artery, innominate, 94.
pulmonary, 106.
Articulation, pubic, 35.
Articulations, freely movable, 48.
immovable, 47.
slightly movable, 47.
Auditory nerve, 209, 225.
Auricles of the heart, 84.
Bile, 172.
Bladder, 180.
Blood, 73.
circulation of, 109.
clotting of, 78.
fibrin of, 79.
functions of, 73, 80.
Blood, plasma of, 77.
red corpuscles of, 76.
white corpuscles of, 75.
Blood-vessels, 81.
Bodily heat, 196.
Bone, cribriform plate of ethmoid, 36.
development of, 22.
ethmoid, 36.
hyoid, 38.
structure of, 20.
Bones, 23.
flat, 29.
irregular, 35.
long, 24.
short, 28.
table of, 45.
Brain, the, 203.
different parts of, 204.
membranes of, 203.
weight of, 207.
Bread, composition of, 151.
Bronchial tubes, 133.
Bursse, 50.
Caecum, 162.
Canal, alimentary, 153.
central, of spinal cord, 210.
Canals, Haversian, 22.
Capillaries, 90.
Carbo-hydrates, 148.
Carbonic acid, excretion of, 179.
proportion of, in air, 138.
Cartilage, 18.
Cavity, buccal, 155.
dorsal, 2.
pelvic, 43.
thoracic, 45.
ventral, 2.
Cell, the, 4.
Cerebellum, 205.
265
266
INDEX.
Cerebro-spinal system, 203.
Cerebrum, 206.
Chordae tendineae, 84.
Choroid coat of eye, 229.
Chyle, 172.
Chyme, 171.
Cilia, 11.
Circulation, arterial, 110.
capillary, 112.
foetal, 115.
general, 109.
portal, 103.
pulmonary, 109.
summary of, 114.
Coccyx, 40.
Colon, 162.
Colour, 224.
Conjunctiva, 144, 229.
Connective tissue, proper, 14.
Connective tissues, 13.
classification of, 13.
Contractility, muscular, 52, 54.
Cord, spinal, 210.
Corpuscles, red, 75.
tactile, 11)1, 216.
white, 76.
Cranium, 41.
Crystalline lens, 232.
Development of blood-vessels and cor-
puscles, 117.
of bone, 22.
of muscular tissue, 55.
Diaphragm, 65.
Diastole, 86.
Diet, 151.
Digestion, 169, 174.
Digestive juices, bile, 172.
gastric, 171.
intestinal, 173.
pancreatic, 172.
saliva, 170.
Diploe, 30.
Duct, cystic, 167.
hepatic, 167.
nasal, 23(5.
pancreatic, 162.
right lymphatic, 121.
thoracic, 121.
Dura mater, 203.
Ear, the, 223.
Elastic tissue, 16.
Elimination, 179.
Epidermis, I'.K).
Epithelial tissue, 8.
Epithelium, simple, 10.
simple ciliated, 11.
simple columnar, 10.
simple glandular, 11.
simple pavement, 10.
stratified, 9.
transitional, 10.
Eustachian tube, 158, 224.
Eye, the, 227.
Eye-brows, 234.
Eye-lids, 234.
Fallopian tubes, 241.
Fasciae, 16.
Fats, 148.
absorption of, 176.
digestion of, 172.
Fibre, non-striated muscular, 54.
striated muscular, 53.
Fibrin, 79.
Fibro-cartilage, 19.
Fibrous tissue, 15.
Fontanelle, 42.
Foramen, thyroid, 35.
Food, 14(5.
Food-stuffs, classified, 147.
Gall-bladder, 167.
Ganglia, 203.
of spinal nerves, 212.
of sympathetic system, 214.
Gastric juice, 171.
Glands, of Brunner, 161.
lachrymal, 2M5.
of Lieberkuhn, 161.
lymphatic, 124.
mammary, 244.
Meibomian, 235.
salivary, 156.
sebaceous, 193.
secreting, 142.
solitary, 126.
sweat, 194.
Glottis, the, 130.
Glycogen, 176.
Gullet, the, 158.
Haemoglobin, 75.
Hairs, 192.
Heart, beat of the, 86.
cavities of the, 84.
position of the, 82.
sounds of the, 88.
structure of the, 82.
Heat, distribution of, 197.
production of, 196.
INDEX.
267
Heat, regulation of, 197.
Humours of the eye, 228, 232.
Ileo-orecal valve, 1(52.
Impulses, nervous, 199.
Inflammation, 113.
Insensible perspiration, 195.
Intestinal juice, 173.
Intestine, large, 1G2.
small, 1GO.
Iris, 229.
Joints, classification of, 47.
movements of, 49.
table of, HO.
Juice, gastric, 171.
intestinal, 173.
pancreatic, 172.
Kidneys, blood-supply of, 183.
position of, 180.
structure of, 182.
Labyrinth of ear, 225.
Lachrymal glands, 235.
Lacteals, 119.
Larynx, 129.
Ligamenta subflava, 16.
Ligaments, 15.
annular, 70.
Light, 231.
Linea alba, 61.
Liver, position of the, 164.
secretion of bile by the, 167.
structure of the, 1(55.
Lungs, position of the, 134.
structure of the, 133.
Lymph, 73, 121.
functions of, 123.
movements of, 122.
Lymphatic glands, 121.
Lymphatic vessels, 119.
Mammary glands, 244.
Mastication, 1(59.
Meat, composition of, 151.
Medulla oblongata, 204.
Medullated nerve-fibres, 201.
Membrane, basement, 145.
mucous, 144.
serous, 91.
synovia!, 50.
Metabolism, (5.
Milk, composition of, 151.
Minerals, as food, 149.
Mouth, the, 155.
Muscular tissue, 52.
development of, 55.
regeneration of, 56.
Muscles, abdominal, action of, 64.
attachment of, DO.
of head and face, 58.
of neck and trunk, CO.
of lower extremity, 68.
table of chief, 71.
of upper extremity, 67.
Nails, 192.
Nares, anterior and posterior, 221.
Nerve-cells, 200.
Nerve-fibres, 200.
Nerves, afferent or sensory, 202.
cranial, 207.
degeneration of, 216.
efferent or motor, 202.
regeneration of, 216.
spinal, 212.
termination of, 216.
Nervous system, 202, 215.
Nervous tissue, 199.
Nitrogenous waste, excretion of, 186.
Nose, the, 221.
Nucleus, 7.
(Edema, 123.
(Esophagus, 158.
Organs, 3.
sensory, 218.
Osseous tissue, 20.
Ovary, 241.
Ovum, description of, 243.
Oxidation, 139.
Oxygen, combination of, with haemo-
globin, 76, 139.
Pancreas, 1(53.
Pancreatic juice, 172.
Papilla, 146, 191, 219.
Patella, 35.
Pelvis, 43.
Pepsin, 171.
Peptone, 171.
Pericardium, 83.
Periosteum, 21.
Peritoneum, 91.
Perspiration, 194.
Peyer's patch, 127.
Pharynx, 157.
Pia mater, 204.
Plasma of the blood, 77.
Pleura, 91, l.T>.
Pons Varolii, 205.
268
INDEX.
Pressure, atmospheric, 135.
Process, 25.
alveolar, 38.
external malleolus, 28.
internal malleolus, 28.
odontoid, 39.
olecranon, 26.
Proteids, 147.
Protoplasm, 4.
Ptyalin, 170.
Pulse, 110.
Pylorus of stomach, 159, 171.
Pyramids of kidney, 182.
Pyrexia, 197.
Receptacle of the chyle, 121.
Rectum, 162.
Regeneration of muscular tissue, 56.
Respiration, 129, 135.
abdominal or diaphragmatic, 66.
costal, 65.
effect of, upon air outside the body,
137.
effect of, upon air within the lungs,
136.
effect of, upon the blood, 138.
Retina, 230.
Ribs, 33.
Sacrum, 40.
Saliva, 170.
Salivary glands, 156.
Sebaceous glands, 193.
Secreting glands, 142.
Secretion, 142.
Sensory organs, 218.
Sight, long and near, 233.
Skeleton, 23.
Skin, functions of the, 195.
structure of the, 188.
Skull, 41.
Sound, 226.
Sphincter muscle of the bladder, 181.
of rectum, 162.
Spinal cord, 210.
Spine, 38, 40.
Spleen, 127.
Stomach, the, 158.
Suprarenal capsules, 187.
Suture, 47.
Sweat-glands, 194.
Symphysis pubis, 35.
Synovia, 50.
System, cerebro-spinal, 203.
nervous, 202.
sympathetic, 214.
Systole, 86.
Teeth, 156.
Temperature of blood, 74.
of body, 196.
Tendons, 16.
Tension, arterial, 111.
Thorax, 45.
Tissue, adipose, 17.
areolar, 14.
cartilaginous, 18.
connective, proper, 14.
elastic, 16.
epithelial, 8.
fibrous, 15.
muscular, 52.
nervous, 199.
osseous, 20.
Tissues, classification of, 4.
Tongue, the, 219.
Tonsils, 127.
Trachea, 131.
Tympanum, 224.
Urea, 186.
Ureters, 180.
Urethra, 181.
Urine, composition of, 186.
excretion of, 185.
secretion of, 184.
Uterus, 238.
Uvula, 155.
Vagina, 237.
Valve, bicuspid or mitral, 85.
tricuspid, 84.
Valves in veins, 89.
semilunar, 86.
Valvulae conniventes, 160.
Vein, portal, 103.
Veins, of head and neck, 104.
of lower limb, 105.
pulmonary, 100.
right and left azygos, 105.
structure of, 89.
systemic, 103.
table of, 107.
of upper limb, 104.
Vena cava, inferior, 106.
superior, 105.
Venae comites, 103.
Ventricles of the brain, 206.
of the heart, 84.
Vertebrae, 39.
Villi, 146, 161.
Vocal cords, 130.
Waste products, 179.
Water, 148.
Zona pellucida, 243.
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