and lymph streams. This material, derived from the
304 SECRETION
circulation, is changed within the gland by some
unknown phenomena and secreted by the cells of
the ductless glands to be taken into the blood and
lymph direct, and thus aid in promoting the metab-
olism of the body. They possess no ducts.
The Thyroid Gland. This is a very vascular organ,
situated at the front of the neck, overhanging the
upper rings of the trachea and laterally extending as
high as the oblique line on the alse of the thyroid
cartilage, and as low as 1 inch above the upper border
of the sternum, when the head is extended. It weighs
about 1 ounce; slightly heavier in the female. It
has three lobes two lateral connected by an isthmus ;
and one third or middle lobe. It is firmly attached to
the cricoid cartilage and posterior fascia of the trachea
by two lateral or suspensory ligaments and its lobes
and isthmus are enclosed within a fibrous capsule
derived from the pretracheal portion of the deep
fascia of the neck.
The isthmus lies on the second and third ring of
the trachea, and measures about J inch in breadth
and depth.
The functions of the thyroid are not thoroughly
understood. It is an established fact, however, that
when the gland is secreting more or less than the
normal quantity, changes in development arise as a
result of some physiologic disturbance interfering
with the general metabolism of the body; as cretinism,
a condition occurring in infants and children as a result
of a congenital absence or arrested development of the
gland; myxedema, a condition (occurring in adults) of
the skin in which it becomes thickened, giving rise to a
change in the patient's expression, due to the face becom-
ing broader, swollen, and flattened. The mind is dull,
the subject is almost idiotic as regards the mental
condition. Myxedema is due to atrophy or some
pathologic change taking place in the gland which
interfered with its normal secretion: removal of the
THE SECRETING GLANDS 305
gland by operation gives rise to a similar condition,
called cachexia strumipriva ; an increase in the secretion
from the thyroid gland causes a condition characterized
by protrusion of the eye-balls the patient's expression
is staring and frightened palpitation of the heart
and enlargement of the gland, termed exophthalmic
goitre or Graves' disease. An enlargement of the
thyroid gland, which is gradually progressive, can
be seen in the necks of people living in or coming
from certain localities where the diseased condition
is due to the drinking water containing lime; this is
termed ordinary goitre.
The Parathyroid Glands. These are small, reddish-
brown bodies, composed of masses of cells, arranged
in a more or less reticular manner with numerous
intervening bloodvessels. They are usually found
one on either side (the superior) at the level of the
lower border of the cricoid cartilage, behind the
junction of the pharynx and esophagus, and in front
of the pre vertebral fascia. The lower are just below
the lower edge of the lateral lobe one on either side.
There are usually four, but may be only three, or again,
as many as six or eight. Their location is variable.
The functions of the parathyroids have not been
sufficiently established to warrant a description
within these pages. However, their removal from
animals has given rise to tetany, characterized by
spasmodic contractions and paralyses of certain
groups of muscles, convulsive seizures, and death.
Spleen. The spleen is the largest of the ductless
glands. It is found in the left hypochondrium, entirely
surrounded by peritoneum, except around the hilum,
which attaches it to the fundus of the stomach (the
gastrosplenic omentum). It is purplish in color,
oblong, flattened, tetrahedral form, soft, of a very
friable consistency, and highly vascular. It measures
5 inches in length, 2 to 3 inches in width, and 1 to 1J
inches in thickness at the centre. It weighs 6J ounces,
20
306 SECRETION
The spleen is attached to the stomach by the
gastrosplenic omentum. The lienorenal ligament is a
peritoneal fold, which attaches it to the upper pole of
the left kidney, and the phrenocolic assists to support
it by its attachment to the diaphragm.
The spleen when seen under the microscope shows
a capsule of fibrous tissue which sends off slips or
trabeculse from its under surface; these spread out
and form a connective-tissue supporting frame-work
for the contents of the organ, which consists of a
dark red semifluid mass called the splenic pulp, filling
the spaces between the fibrous tissue. Microscopically
the splenic pulp is seen to consist of adenoid tissue,
rich in leukocytes or white-blood cells, arranged in
small groups throughout the pulp, called Malpighian
corpuscles; red corpuscles are also present in the pulp.
The Functions of the Spleen. Owing to the numbers
of red cells seen in the splenic pulp undergoing all
stages of disintegration, it has been concluded that
the spleen aids in the destruction of red cells; another
theory is based on the presence of the large quantity
of white cells within the Malpighian corpuscles, that
the spleen is the chief centre for the production of
white cells, and thus contributes to the formation of
the blood.
The spleen is larger in childhood than old age;
it is enlarged during and after digestion. In typhoid
fever and malaria a marked increase can be noted;
also in various blood diseases.
Thymus Gland. The thymus gland is a temporary
organ, attaining its full size at the end of the second
year and gradually shrinking until puberty, when
it entirely disappears. Consists of two lateral lobes
placed in close contact along the median line. It
is found in the superior mediastinum, covered by the
sternum and the origins of the sternohyoid and sterno-
thyroid muscles; below, it rests upon the pericardium,
and separated from the arch of the aorta and great
THE SECRETING GLANDS 307
vessels by fascia. In the neck it lies on the front
and sides of the trachea beneath the sternohyoid
sternothyroid muscles.
Suprarenal Glands. The suprarenal glands are two
flattened bodies, of a yellowish color, found in the
epigastrium, lying behind the peritoneum, and above
and in front of the upper extremity of each kidney.
They are triangular in shape, H to nearly 2 inches in
length, less in width, and J of an inch in thickness.
The Functions of the Suprarenal Glands. They
secrete a substance, termed adrenalin (takamine,
Aldrich) or epinephrin (Abel), which is absorbed
by the blood, and stimulates to increased activity
the muscle fibers of the heart and arteries, and thus
aids in maintaining the normal blood-pressure. Dis-
ease of the suprarenal glands causes a bronzing of
the skin and mucous membranes with disturbances
of nutrition, muscular weakness, and anemia. Gradu-
ally the heart becomes weak; the pulse is soft and
feeble, indicating a general reduction in blood-pressure
from interference with the secretion of the active
physiologic material from the cells of the gland.
Addison's disease is the name applied to this condition,
as he first described the disease.
The Pituitary Body (Hypophysis). The pituitary
body is a small glandular body situated at the base
of the brain, lodged in the sella turcica of the sphenoid
bone. It is divided into an anterior and posterior
lobe; the former is reddish in color, is larger than the
posterior lobe, and is derived from an invagi nation of
the epiblast of the mouth cavity, and shows micro-
scopically gland tissue; the posterior lobe is yellowish
gray in color, and represents an outgrowth from
the brain. It is connected by a thin slip to the
infundibulum.
The functions of the pituitary are still under inves-
tigation; however, it has been proved by experiment
that an injection of the extract made from the internal
308 SECRETION
secretion of this gland will cause an increase in the
force of the heart-beat and a rise in blood-pressure
by stimulating the arterioles. According to Ho well,
the extract given intravenously from the posterior lobe
will cause a rise in blood-pressure and slow the heart-
beat, the extract from the anterior lobe being negative
as to its effect on the circulatory and respiratory
organs. Disease of the pituitary body will give rise
to the condition of acromegalia, in which there is a
marked enlargement of the bones of the face and
extremities. When diseased in early life it is respon-
sible for the progressive changes, characterized by
extreme growth of the body, termed gigantism; also
a marked increase of fatty tissue.
Carotid Glands. The carotid glands or bodies are
small reddish-brown bodies, oval in shape, their long
diameter measuring i of an inch. They are found in
the cervical region, at the bifurcation of the common
carotid artery into the internal and external carotid
trunks.
Coccygeal Gland. The coccygeal gland or body,
or Luschka's gland, is as large as a millet-seed, found
at the tip of the coccyx. It is connected with middle
sacral artery.
QUESTIONS
1. Give the difference between an external and internal secretion.
2. Name some of the external secretions.
3. How are secretions utilized by the tissues of the body?
4. Name the secreting membranes of the body.
5. Name the organs of internal secretion.
6. Give the general arrangement of the structures seen in a
secretory gland.
7. By what structure does a secreting gland communicate with
a membrane upon which its secretion is poured out?
8. What part does the nerve system play in regard to gland
secretion?
9. What is excretion?
10. Describe the structure of a mammary gland.
11. Is human milk alkaline or acid in reaction?
12. Docs milk contain oil globules?
QUESTIONS 309
13. How much milk is secreted every day by the mammary glands
in a healthy woman?
14. Give the chemical composition of milk.
15. How does woman's milk differ from cows' milk?
16. What is colostrum? Give its function.
17. Which is the largest gland of the body?
18. How much does the liver weigh?
19. How many lobes has it?
20. What structures pass out of and enter the transverse fissure
of the liver?
21. Give the location of the liver in the abdominal cavity.
22. What is the serous membrane surrounding the liver called?
The fibrous capsule?
23. What microscopic structures are seen in the liver lobules?
24. Name the functions of the liver.
25. How is glycogen formed? W'here is it stored in the body
chiefly?
26. Is urea a waste product resulting from metabolism? Which
organs excrete it?
27. What is the function of the gall-bladder? Name its duct.
28. Where is it located?
29. What ducts form the common bile duct?
30. Where does the common bile duct drain?
31. How long is the cystic duct? The common bile duct?
32. To which variety of glands does the pancreas belong?
33. Give the dimensions of the pancreas.
34. Name the duct of the pancreas. Which portion of the duo-
denum does it open into?
35. What is the opening in the duodenum for the common bile
and pancreatic duct called?
36. How does the pancreatic secretion leave the pancreas?
37. Name the organs of internal secretion.
38. Which one of the ductless glands is the largest?
39. Give its dimensions and weight.
40 How is the spleen attached to the stomach? The left kidney?
The diaphragm?
41. Where are the suprarenal glands located in the abdominal
cavity?
42. Name their functions?
CHAPTER XV
THE FACTORS ESSENTIAL TO THE PRO-
DUCTION OF BODY TEMPERATURE
OR HEAT
THE human body maintains an even temperature
during life, due to the results of chemic changes going
on within the tissues and organs of the body as a
result of metabolism. These changes result from the
processes of oxidation taking place in the cells of the
body by the union of oxygen with the elements
carbon and hydrogen, contained within the food we
eat, either before or after they become constituents of
the tissues. During metabolism of the body the food
is again broken up into simple compounds, as carbon
dioxide, w r ater, and urea, which evolve a large portion
of their energy as heat and mechanic activity.
The body is continually giving off heat called
heat dissipation, and this heat dissipation must be
replaced by an equal amount of heat liberation,
called heat production, by the tissues as a result of
metabolism, else the even temperature of the body
would not be maintained, as is necessary for the
normal action of the physiologic processes of the body.
Heat Production. Heat production is derived from
the formation of carbon dioxide, urea, and water, as
a result of oxidation of the tissues by the union of
oxygen with the carbon and hydrogen of the food.
And mechanically each of the following actions
contribute to the production of heat: Contraction
of muscles, during the secretions of glands, the force
exhibited by the nerve system in producing its func-
tions of receiving and conveying impulses throughout
HEAT VALUES OF FOOD 311
the body to accomplish the various actions essential
to the life of the individual.
Heat Dissipation. Heat is given off by warming
the food and liquids consumed, to the temperature of
the body; in warming the air we breathe to the body
temperature; in the evaporation of water from the
lungs and skin ; in the skin it is given off by the pro-
cesses of radiation and conduction.
The quantity of heat essential to the maintenance
of the body temperature and the quantity liberated
is determined experimentally by a study of the heat
values of different foods; another method is by
means of an apparatus called a colorimeter, in which
is collected and measured the heat given off as a
result of oxidation of the food within and given off
from the body daily.
Heat Values of Food. By the first method 1 gram
of food is burned, the hydrogen and carbon of the
food is chemically converted into carbon dioxide and
water as a result of oxidation, and during this change
heat is given off and collected which the experiment has
proved will raise the temperature of a given amount
(1 kilogram) of water. The amount of heat evolved
is expressed in gram or kilogram, degrees or calories.
A calorie is the amount of heat necessary to raise
1 gram of water 1 C. It has been demonstrated
that certain foods produce far more heat than others
(expressed in calories), and hence more or less heat
will be dissipated, and an increase or decrease in
energy will be apparent, dependent upon whether
the diet is rich in proteins, carbohydrates, or fats.
The carbohydrates and fats are reduced, after being
absorbed to carbon dioxide and water, the proteins
are changed to a compound urea with the liberation
of heat, expressed in calories as follows:
1 gram of protein 4.1 calories
1 gram of fat 9.3 calories
1 gram of carbohydrates -.4.1 calories
312 BODY TEMPERATURE OR HEAT
Knowing the above, it is easy to determine the
heat units or calories each quantity of contained
proteins, fats, and carbohydrates in a diet will liberate.
The number of grams of protein are multiplied by
4.1 calories, which one gram of protein evolves; the
number of grams of fat, by 9.3 calories, that one
gram of fat evolves; and the number of grams of
carbohydrates by 4.1 calories, the amount of calories
that 1 gram of carbohydrates liberates. See example:
The quantity of protein consumed daily is
100 gm. = 100 X 4. 10 or 410 calories
The quantity of carbohydrates consumed
daily is 500 gm. = 500 X 4.1 or . . . 2050 calories
The quantity of fats consumed daily is 50
gm. = 50 X 9 . 3 or 465 calories
2925 calories
The average number of calories required by an
individual daily, to maintain an even temperature,
and promote the normal energy of the body, is about
3000. Thus the heat dissipated by the body will
nearly equal the physiologic heat values of the foods
we eat.
The Temperature of the Body. The equalization
of the heat-dissipation and heat-production keeps
the body at a standard temperature. This in olden
times was taken by physicians simply by laying the
hand on the skin. The introduction of the clinical
thermometer has allowed of a more accurate and
scientific means of reading the temperature. The
temperature of the body varies in different locations,
due to the chemic changes resulting from body metab-
olism varying in their intensity and extent in different
parts of the body. This variation would be more
marked were it not due to the fact that the blood
and lymph absorbing the heat, evenly distribute it
to all parts of the body, so that the change in temper-
ature amounts to only a few degrees.
QUESTIONS 313
The normal body temperature in the axilla is
98.6 F. or 37 C. (French). This may be as low
as 97.5 to 98 F. in the early morning, and reaching
to 99 to 99.3 F. in the evening, and denote no abnor-
mal condition of health; by mouth, 98.6 F. or 37 C.;
rectum, 100.4 F. or 38' C.; vagina, 100.9 F. or
38.3 C. In infancy under six years of age, 99.4 F.
or 37.4 C.; in the aged (sixty to eighty years), 98.2
F. or 36.8 C.
\
QUESTIONS
1. How does oxidation of the tissues effect heat production?
2. What mechanical actions of the body aid in heat production?
3. How is heat dissipation brought about?
4. What must occur in the tissues to equal heat dissipation in
order to maintain an even body temperature?
5. How are heat values expressed?
6. How many calories will 1 gram of protein produce? 1 gram
of fat? 1 gram of carbohydrates?
7. What is a calorie.
8. What is the average number of calories required to maintain
an even temperature and promote the normal energy of the body?
9. What relation should the heat dissipated by the body bear to
the heat values of the foods we consume?
10. Give the normal temperature when taken by mouth, axilla,
and rectum.
CHAPTER XVI
THE ANATOMY AND PHYSIOLOGY OF THE
URINARY APPARATUS (ORGANS); THE
SKIN AND ITS APPENDAGES
THE URINARY ORGANS
. THE urinary organs include the kidneys, which
secrete or excrete the urine ; the ureters convey it to the
bladder, where it is retained until voided (micturition) ;
then the urethra which discharges it from the body.
The Kidneys (Renes). The kidneys are situated in
the abdominal cavity on each side of the vertebral
column, resting on the psoas magnus and the quad -
ratus lumborum muscles'. They are behind the peri-
toneum and correspond to the space included between
the upper level of the twelfth thoracic above, and
opposite the third lumbar vertebra below. The right
kidney is lower than the left. In the female they are
a little lower than in the male.
Each is bean-shaped, measures about 4 to 4f inches
in length, 2| in breadth, and 1 to If inches in thick-
ness, and weighs about 4 to 6 ounces. They lie in the
right and left hypochondriurn, the epigastrium, and
the right and left lumbar regions.
Fixation of the Kidney. The kidney is embedded in
a mass of fatty tissue (capsule adiposa) surrounded by
a fibrous sheath named the fascia renalis continuous
with the subperitoneal fascia.
The Structure of the Kidney. The kidney is made
up of a series of tubules supported by a frame-work
of connective tissue, and surrounded by small capil-
THE URINARY ORGANS
315
laries, lymphatics, and nerves. On examining the
incised kidney its surface presents an inner two-thirds,
VEINS
Fio. 114
INFERIOR PHRENIC
ARTERIES
CESOPHAGUS
Posterior abdominal wall, after removal of the peritoneum, showing
kidneys, suprarenal capsules, and great vessels. (Corning.)
316
THE URINARY APPARATUS
called the medulla, measuring f to f of an inch in
thickness; and an outer one-third called the cortex,
measuring J to J inch in thickness.
Fio. 115
COLUMN OF
BERTIN
MEDULLARY
PYRAMID
URETER
MEDULLARY
PYRAMID
COLUMN OF
BERTIN
Vertical section of kidney, showing the secreting portion, the vessels,
and the beginnings of the ureter. (Testut.)
The Medulla. This consists of small pyramids,
ten to twenty in number. The base of each is
directed toward the cortex and the apices point
toward the pelvis of the ureter, where they project
into the calices of the same; each calix receives one,
THE URINARY ORGANS 317
two, or three papillae. Each papillae has a number
of minute openings upon its apex for the excretory
ducts of the pyramids; the latter pour the urine into
the pelvis of the ureter. These orifices open into
tubules and are practically the external outlet of
the uriniferous tubules. They pass toward the base
of the pyramid, and within this region are known as
the tubes of Bellini. Continuing they enter the cortex,
where they become enlarged and twisted, and follow
an extremely tortuous course to turn backward into
the medullary portion for some space, and are called
in this position the ascending limb of the loop of Henle ;
they curve upon themselves again, and, while still
within the medullary portion, are known as the
descending limb of the loop of Henle ; reenter the cortex,
expand again, and becoming twisted (convoluted
tubule), end in an ovoid enlargement termed Bowman's
capsule, in which is a small collection of bloodvessels
the glomerulus, or Malpighian tuft. The capsule and
contained bloodvessels, the glomerulus, constitute
the small reddish bodies called renal or Malpighian
corpuscles, which are scattered throughout the cortex
of the kidney.
The Cortex. This is reddish brown in appearance,
and lies just beneath the capsule of the organ. It
contains the Malpighian corpuscles. When examined
with a lens it has a light colored, ray-like appearance.
The lighter rays are termed the medullary rays, and
are found by the collection of uriniferous tubules (loops
of Henle) from the medullary portion. The darker
colored intervening substance is called the labyrinth,
from its complexity of structure, and is composed of
the Malpighian corpuscles and the various loops of the
tubules.
The Uriniferous Tubules. Microscopic examination
of the kidney substance is the only method by which
the uriniferous tubules can be seen and understood.
318 THE URINARY APPARATUS
However, I will endeavor to make as clear as possible
their course. The tubules practically start in the cortex
as a capsule of Bowman, which surrounds the capillaries
(glomerulus) . The tubules run a very irregular and
distorted course, and finally end in straight tubules
which pass through the pyramids to empty into the
calices of the pelvis of the ureter. Bowman's capsule
is lined by flattened epithelial cells resting on a very
delicate basement membrane. The convoluted por-
tions of the tubules are lined with cuboidal epithe-
lium and the loops of Henle contain more or less
flattened epithelium.
The Ureters. The ureters are two tubes, and con-
vey the urine from the kidney to the bladder. The
urine is collected from several minor calices, ten to
twenty in number, which open into the major calices;
the latter by their junction form the pelvis or dilated
portion of the ureter. It is on a line with the first
lumbar vertebra.
The ureter proper is divided into an abdominal
portion (pars abdominalis) and a pelvic portion (pars
pelvina). They are 10 to 12 inches in length and - of
an inch in diameter. The walls are from 1 to 2 mm.
thick.
The Urinary Bladder (Vesica Urinaris) . The bladder
is situated in the pelvic cavity, but in infancy and
when distended in the adult, extends into the hypo-
gastrium. It measures when moderately distended,
5 to 5J inches in length, 4J in width, and 3 inches
from before backward. It holds a pint of urine
without discomfort. The bladder presents a superior,
antero-inferior, and two lateral surfaces; a base or
fundus, and an apex or summit.
The interior of the bladder shows the mucous mem-
brane thrown into rugae, the orifices of the ureters, and
the trigone, also the orifice of the urethra, which empties
the urine from the bladder. The ureteral orifices arc
THE URINARY ORGANS 319
about 2 inches apart when the bladder is moderately
distended. The trigone is a smooth, triangular surface,
paler than the rest of the mucous membrane. It is
bounded at the basal angles to the orifices of the ureters,
and the apex to the internal urethral orifice. The
ureteral folds are the prolongations extending beyond
the ureteral orifices, of the transverse ureteral fold
containing muscle fibers covered by the mucous
membrane. The internal urethral openings is sur-
rounded by a circular fold of mucous membrane,
called the annulus urethalis.
The ligaments of the bladder are: true and false.