This document outlines the morphology and functional characteristics of the endocrine system, focusing on the pituitary gland, pineal gland, and adrenal glands. It details the structure, functions, and hormonal output of these glands, as well as their roles in regulating body metabolism and development. Additionally, it discusses the variations in size and function of these glands throughout different life stages.

1. Department of Anatomy
• Anatomy: Morphofunctional
characteristics of the organs of the
endocrine apparatus. Pituitary gland,
pineal gland, adrenal glands.
• Prepared by prof. Dyusembaeva A.T.

2. Еndocrine glands
The glands that secrete a secret into the ducts called exocrine system glands. Glands, the secret of
which goes directly into the blood or lymph (because they do not have ducts) are called endocrine
system glands. The process of production and secretion of active substances by endocrine glands is
called glands of internal secretion and the substances produced by them called hormones (Greek.
Hormao- excite). The hormones are biologically active substances, which even in small quantities
affect the metabolism, growth and development of organism. They can perform distant regulation of
the organ activities. To maintain the growth, functioning and development of the body human
organism requires a definite level of hormones in the blood. In those cases where there is a lack of a
definite hormone, it’s called hypofunction of the given gland. When the hormones are produced by a
gland in excess, it’s called hyperfunction. The definite hormone acts on cells of only one specific type.
These cells are called target cells. Some hormones (e.g., thyroid hormone) affect more than one cell
and all of them should be considered as target cells for a given hormone. The endocrine glands have a
small size, but they are richly supplied by blood. The hormones are delivered to the target-organs
through the blood. This is humoral regulation of these organs activities. All processes in the body are
controlled by the central nervous system. Such dual regulation of the organ activities is called
neurohumoral.

3. Classification of endocrine organs
• Classification of endocrine organs
• 1. The glands of endodermal origin - branchiogenic
group, developing from the epithelium of the pharyngeal
intestine (gill pockets) - thyroid, parathyroid glands;
• 2. The glands of endodermal origin - enteric group,
developing from the epithelium of intestinal tube -
endocrine part of the pancreas;
• 3. The glands of mesodermal origin - interrenal system,
adrenal cortex, the interstitial cells of the genital glands;
• 4. The glands of ectodermal origin - neurogenic group,
derivatives of the anterior part of the neural tube -
hypophysis, epiphysis;
• 5. The glands of ectodermal origin, derivatives of
sympathetic nervous system - adrenal medulla,
paraganglia;

4. Hypophysis
• The pituitary gland (hypophysis) is
located in the pituitary fossa of the
Turkish saddle of the sphenoid bone, it is
separated from the brain by the process
of the dura mater - the saddle
diaphragm. The pituitary gland is
connected by a funnel with the
hypothalamus and together with it forms
the so-called hypothalamic-hypophysial
system, which actively influences many
organs of the human body with its
hormones.

5. The pituitary gland, hypophysis
• The anteroposterior dimension of the pituitary gland
is 5–15 mm, the transverse diameter is 10–17 mm,
and the vertical diameter is 5–10 mm. Weight -0.5-
0.6 g.
• Outside, the pituitary gland is covered with a
capsule. In the pituitary gland, the anterior lobe
(adenohypophysis), the intermediate lobe and the
posterior lobe (neurohypophysis) are distinguished.
• The anterior lobe is formed from the protrusion of
the primary oral cavity (Rathke's pocket), and the
posterior lobe from the protrusion of the bottom of
the 3rd ventricle of the brain during embryonic
development. Also, the anterior and posterior lobes
of the pituitary gland differ in function: the
adenohypophysis independently produces
hormones, and the neurohypophysis only
accumulates and activates them.

6. Hypophysis
• 1. The anterior lobe, lobus anterior, is larger
than the posterior lobe. The anterior lobe has:
• 1.distal part, pars distalis, which occupies the
anterior part of the pituitary fossa
• 2.intermediate part, pars intermedia, located on
the border with the posterior lobe
• 3. tuberous part, pars tuberalis, going up and
connecting with the funnel of the hypothalamus.
• The adenohypophysis represents the majority of
the pituitary gland and accounts for 75% of its
total mass. Due to the abundance of blood
vessels, the anterior lobe has a pale yellow color
with a reddish tint.
• The parenchyma of the anterior pituitary gland
consists of glandular cells, which are separated
by numerous cords-trabeculae. Sinusoidal blood
capillaries are located between the strands.

7. Hypophysis
In the anterior lobe of the pituitary gland,
several types of endocrine cells are
distinguished: acidophilic, basophilic,
chromophobic adenocytes.
A) Acidophilic adenocytes synthesize
prolactin and growth hormone.
1.Prolactin, lactotropic hormone,
proliferation of mammary glands and milk
by mammary glands.
2. Growth hormone regulates the growth
of bones, muscles, organs.
C) Basophilic adenocytes are subdivided
into gonadotropic, corticotropic and
thyroid-stimulating endocrinocytes.

8. Hypophysis
1.Gonadotropic endocrinocytes secrete
follicle-stimulating (FSH), luteinizing (LH)
hormones. FSH stimulates the growth of
follicles in the ovaries, the secretion of
estrogen and ovulation in women, Luteinizing
hormone stimulates ovulation, the formation
of the corpus luteum, the development and
maturation of germ cells.
2. Corticotropic endocrinocytes synthesize
adenocorticotropic hormone (ACTH), which
stimulates the formation of glycocorticoids by
the adrenal cortex.
3. Thyroid-stimulating endocrinocytes produce
thyroid-stimulating hormone (TSH), which
regulates the development of the thyroid
gland.
E) Chromophobic adenocytes are possible
precursors of chromophilic adenocytes.

9. Hypophysis
II. The intermediate lobe of the pituitary
gland is formed by basophilic adenocytes
that synthesize
melanocytocytocystostimulating
hormone or intermedin, which controls
the formation of the melanin pigment.

10. Posterior pituitary gland
• III.The posterior lobe of the pituitary gland, lobus
posterior, s. neurohypophysis, consists of
• 1. nerve lobe, lobus nervosus, s. pars nervosa, which
is located at the back of the pituitary fossa
• 2. funnel, infundibulum, located behind the tuberous
part of the adenohypophysis. The posterior lobe of
the pituitary gland is formed by neuroglial cells
(pituicites), nerve fibers coming from the
neurosecretory nuclei of the hypothalamus to the
neurohypophysis, and neurosecretory bodies.
• The neurohypophysis does not synthesize hormones.
Vasopressin (antidiuretic hormone) and oxytocin,
synthesized by neurosecretory cells of the supraoptic
and paraventricular nuclei of the hypothalamus, are
transported along the axons of neurons and released
into the capillaries of the neurohypophysis.
• Antidiuretic hormone has a vasoconstrictor and
antidiuretic effect. Oxytocin stimulates the contraction
of the myometrium of the uterus, myoepithelial cells
of the mammary glands, milk secretion.

11. Hypophysis
• Innervation: sympathetic fibers
(from the internal carotid plexus).
Blood supply: upper and lower
pituitary arteries (from the
internal carotid and arterial circle
of the large brain). Venous blood
from the hemocapillary network
of the pituitary gland through the
veins enters the cavernous and
intercavernous sinuses.

12. AGE FEATURES OF THE HYPOPHYSIS
• Differentiation of pituitary adenocytes begins at the 9th week of
intrauterine development and ends by the time of birth.
• In the postnatal period, acidophilic growth hormones are activated,
which is explained by the increased demand and production of growth
hormone.
• During puberty, the number of basophilic cells increases. The average
weight of the pituitary gland in newborns is 0.12 g.
• Organ mass doubles by 10 and triples by 15 years. By the age of 20, the
mass of the pituitary gland reaches its maximum and averages 530-560 g,
in subsequent age periods the mass of the organ practically does not
change.
• After 60 years, there is a slight decrease in the mass of the gland.

13. Epiphysis
•The pineal gland (glandula
pinealis) or the pineal gland
(corpus pineale), is the epiphysis
of the brain, is part of the
diencephalon, the epithalamus,
located in the groove between
the upper hillocks of the roof of
the midbrain. The pineal gland is
ovoid, 8–15 mm long and 6–10
mm wide.

15. Epiphysis
The pineal gland is covered with a connective tissue capsule,
from which connective tissue trabeculae go into the
parenchyma, dividing the parenchyma of the gland into
lobules.
The parenchyma of the gland is represented by specialized
glandular cells pinealocytes (light and dark) located by
anastomosing strands and surrounded by gliocytes
(modified astrocytes) that perform a supporting function.
• In the stroma, around the destroyed cells, crystals of
phosphates and calcium carbonates are deposited -
epiphyseal nodules - cerebral sand. In the interlobular
trabeculae, intraorgan vessels and nerves pass, and
melanocytes and tissue basophils are also located here.
Pinealocytes synthesize 1.melatonin, an antagonist of the
melanostimulating hormone of the pituitary gland, and
2.serotonin. The hormone melatonin is produced at night,
and serotonin is produced during the day. Melatonin affects
pigment cells, causing their discoloration, inhibits sexual
development, regulates the biological rhythms of the body,
affecting sleep.
The pineal gland affects the activity of the adeno- and
neurohypophysis, pancreatic islets, parathyroid glands,
adrenal glands, gonads, thyroid gland, exerting a mainly
suppressive effect on these glands.

16. AGE FEATURES OF EPIPHYSIS
• By 3.5 months of embryogenesis, the pineal gland is
structurally formed, but the cells are not completely
differentiated even at birth - dark pinealocytes
predominate (in adults, light cells). By 1 year of life,
differentiation ends. From 6 months of age, neuroglia
grows intensively, then the amount of connective tissue
increases, and cerebral sand begins to be deposited.
• The maximum development of iron reaches 5-6 years,
and after 7 years, the reverse development begins.
• The average weight of the gland during the first year of
life increases from 7 to 100 mg. By the age of 10, the
mass almost doubles and subsequently remains almost
unchanged.
• In mature and especially often in old age, in the pineal
gland, in addition to deposits of brain sand, cysts can
appear, and therefore, the size and mass of the gland
can be much larger than the indicated average figures.

17. Epiphysis hormones
• Epiphysis hormones
• In total, pinealocytes produce about 40 regulatory peptides. Of these, the most important
are -
• Melatonin - produced mainly at night, it is a hormone of photoperiodicity, is an antagonist
of melanostimulating hormone, inhibits the secretion of gonadoliberin, reduces the activity
of the gonads.
• Serotonin - produced mainly during the daytime. Strengthens the function of the thyroid
gland, the production of STH and sex hormones. This hormone is also called the hormone of
aggression.
• Arginine - vasotocin - inhibits the secretion of FSH and LH.
• Antigonadotropic peptide - inhibits the secretion of gonadoliberin.
• Adrenoglomerulotropin - stimulates the secretion of aldosterone and adrenaline by the
adrenal glands.
• Hyperkalemic factor - increases the level of potassium in the blood.
• Diuretic factor - an antagonist of antidiuretic factor (vasopressin)
• Sleep factor - acts on the sleep nerve center in the hypothalamus.

18. The adrenal gland
• The adrenal gland, glandula
suprarenalis, is a paired organ
located retroperitoneally directly
above the upper pole of the kidney.
The adrenal gland has the shape of a
cone flattened from front to back
with an expanded base and a thin
apex. In the adrenal gland, the front
surface, the facies anterior, the
posterior surface, the facies posterior
and the lower surface, the facies
inferior, are distinguished.

19. The adrenal gland
• The length of the adrenal gland is 4–6 cm,
height - 2–3 cm, thickness, anteroposterior
size - 0.2–0.8 cm. The mass of the adrenal
gland in an adult is 12–13 g. The posterior
surface of the right and left adrenal glands is
adjacent to the diaphragm, the lower, renal
surface is adjacent to the upper pole of the
kidney. The medial edge, margo medialis, of
the right adrenal gland is bordered by the
inferior vena cava, the left - by the aorta. In
front, both adrenal glands are covered by
the renal fascia and the parietal peritoneum.
On the front surface of the adrenal gland,
there is a small groove - the gate, hilum,
through which vessels and nerves pass.

20. The adrenal gland
• Outside, the adrenal gland is covered with a
connective tissue capsule tightly fused with the
parenchyma. In the parenchyma, cortical and
medulla are distinguished.
• In the cortical substance, or cortex, cortex, there
are glomerular (zona glomerulosa), bundle (zona
fasciculata) and reticular zones (zona reticalaris),
located on the border with the medulla.
• 1. The glomerular zone is formed by small cells
arranged in the form of glomeruli and synthesizing
the mineralocorticoids - aldosterone.
• 2. The bundle zone is the widest part of the
adrenal cortex. The cells of this zone, which
produce glucocorticoids - hydrocortisone and
corticosterone, form columns oriented
perpendicular to the surface of the organ.

21. The adrenal gland
• 3. The reticular zone consists of small
cell clusters formed by small cells that
secrete androgens and estrogens.
• The medulla, medulla, of the adrenal
glands is formed by clusters of large
cells, among which epinephrocytes are
distinguished, synthesize adrenaline
and norepinephrocytes, and secrete
norepinephrine.

22. The adrenal gland
• Innervation of the adrenal gland: sympathetic
fibers (from the celiac plexus, preganglionic for the
medulla) and parasympathetic fibers (from the
vagus nerves).
• Blood supply: 15-20 upper adrenal arteries (from
the lower phrenic artery), middle adrenal (aortic
branch) and lower adrenal (from the renal artery)
arteries. From the wide sinusoidal blood capillaries,
the central adrenal vein is formed, which flows into
the inferior vena cava at the right adrenal gland,
and into the left renal vein at the left. Numerous
small superficial veins emerge from the adrenal
gland and drain into the tributaries of the portal
vein.
• The lymphatic vessels drain into the lumbar lymph
nodes.

23. Age features of the adrenal glands
In newborns, 2 parts are distinguished in the adrenal cortex: 1 - the definitive cortex is located
under the capsule in the form of a narrow strip; 2 - makes up about 80% of the entire cortex -
the fetal cortex, in which the glomerular and bundle-reticular zones differentiate. There are
practically no lipids in the cells, there are many cells with symptoms of cytolysis, as a result of
which, by 7 days after birth, the weight of the adrenal gland is half that at birth. These are the
consequences of birth stress! Gradually, the definitive cortex is restored and expanded, and
the fetal cortex is reduced. By the age of 2-3 years, the bundle zone begins to prevail, and the
reticular zone is fully formed. There is little brain matter in newborns, poorly differentiated
cells predominate. Groups of these cells in the form of brain balls are also found in the cortex.
Differentiation of chromaffin cells begins after 4 months of embryogenesis and ends at 3
years of age. By the age of 7-8, the formation of the brain substance ends.
• The final formation of the adrenal cortex is completed during the second childhood (8-12
years). By the age of 20, the mass of each adrenal gland increases by 1.5 times, compared to
the mass of a newborn, and reaches its maximum size (12-13 g). In subsequent age periods,
the size and weight of the organ remains almost unchanged. The adrenal glands in women
are, on average, somewhat larger than in men. During pregnancy, the mass of each adrenal
gland increases. In the later age periods (after 70 years), there is a slight decrease in the mass
and size of the organ.