Review of anatomy and physiology of endocrine system.pptx

1. REVIEW OF ANATOMY AND
PHYSIOLOGY OF
ENDOCRINE SYSTEM
Supriya Batwalkar

2. ENDOCRINE SYSTEM
• The endocrine system is the organ system made up primarily of glands designed to
secrete hormones into the bloodstream. Hormones travel within the bloodstream to
all parts of the body to control important functions, including growth, metabolism,
and reproduction.

5. ADRENAL GLANDS
• There are two adrenal glands, one located above each of the kidneys. Each adrenal
gland has two parts: an inner medulla and an outer cortex.
• The medulla produces the hormones epinephrine and norepinephrine. The outer
cortex produces hormones including aldosterone, cortisol, androgen, and estrogen.
• Function: The adrenal glands produce several hormones that help regulate immune
system, blood pressure, metabolism, response to stress, and other essential
functions.
• Found in: above the kidneys

6. ADRENAL CORTEX
• The adrenal cortex is the outer region and also the largest part of an adrenal gland.
• It is divided into three separate zones:
1. zona glomerulosa-Cells in this layer form oval groups, separated by thin strands of
connective tissue from the fibrous capsule of the gland and carry wide capillaries.[
2. zona fasciculata- Cells in this layer are responsible for producing glucocorticoids such
as cortisol
3. zona reticularis- It produces androgens, mainly dehydroepiandrosterone (DHEA),
DHEA sulfate (DHEA-S), and androstenedione (the precursor to testosterone) in
humans.
• Each zone is responsible for producing specific hormones.

7. ADRENAL MEDULLA
• The adrenal medulla is at the center of each adrenal gland, and is surrounded by
the adrenal cortex.
• The chromaffin cells of the medulla are the body's main source of the
catecholamines, such as adrenaline and noradrenaline, released by the medulla.
• Approximately 20% noradrenaline (norepinephrine) and 80% adrenaline
(epinephrine) are secreted here

8. BLOOD SUPPLY
Arterial supply
• The superior suprarenal artery
• The middle suprarenal artery
• The inferior suprarenal artery
Venous supply
• The right suprarenal vein
• The left suprarenal vein

9. ADRENAL GLAND HORMONES
• Epinephrine: Also called adrenaline, this hormone rapidly responds to stress by
increasing the heart rate and raising blood glucose levels in the blood.
• Norepinephrine: Also called noradrenaline, this hormone works with epinephrine in
reacting to stress. Its primary function is to mobilize the body and brain for action.
• Hydrocortisone: It is commonly known as cortisol or a steroid hormone. It is involved
in regulating body functions like the conversion of fats, and carbohydrates to energy
and also plays a vital role in other metabolic processes.
• Corticosterone: This hormone works with hydrocortisone to control the immune
response and prevents inflammatory reactions.

11. OVARIES
• The ovaries are paired female reproductive organs located within the pelvis, on
either side of the uterus. Roughly egg-shaped themselves, the ovaries primary
function is to produce eggs for fertilization and female hormones including estrogen
and progesterone. Eggs released from the ovaries travel into the fallopian tubes.
• Function: The ovaries' primary function is to produce eggs for fertilization and
female hormones including estrogen and progesterone.
• Found in: The pelvis

12. OVARY
• Each ovary is whitish in color and located alongside the lateral wall of the uterus in a
region called the ovarian fossa. The ovarian fossa is the region that is bounded by the
external iliac artery and in front of the ureter and the internal iliac artery. This area is
about 4 cm x 3 cm x 2 cm in size.
• The ovaries are surrounded by a capsule, and have an outer cortex and an inner
medulla. The capsule is of dense connective tissue and is known as the tunica albuginea.
• Usually, ovulation occurs in one of the two ovaries releasing an egg each menstrual cycle.
• The side of the ovary closest to the fallopian tube is connected to it by infundibulopelvic
ligament, and the other side points downwards attached to the uterus via the ovarian
ligament.

13. LIGAMENTS
• The ovaries lie within the peritoneal cavity, on either side of the uterus, to which
they are attached via a fibrous cord called the ovarian ligament.
• The ovaries are uncovered in the peritoneal cavity but are tethered to the body wall
via the suspensory ligament of the ovary which is a posterior extension of the broad
ligament of the uterus.
• The part of the broad ligament of the uterus that covers the ovary is known as the
mesovarium.
• The ovarian pedicle is made up part of the fallopian tube, mesovarium, ovarian
ligament, and ovarian blood vessels.

14. FUNCTIONS
• At puberty, the ovary begins to secrete increasing levels of hormones.
• Secondary sex characteristics begin to develop in response to the hormones.
• The ovary changes structure and function beginning at puberty.
• Since the ovaries are able to regulate hormones, they also play an important role in
pregnancy and fertility.
• When egg cells (oocytes) are released from the fallopian tube, a variety of feedback
mechanisms stimulate the endocrine system which cause hormone levels to change.
• These feedback mechanisms are controlled by the hypothalamus and pituitary glands.
• Messages or signals from the hypothalamus are sent to the pituitary gland. In turn, the
pituitary gland releases hormones to the ovaries. From this signaling, the ovaries release
their own hormones.

16. PANCREAS
• The pancreas is part of the digestive system. Located behind the stomach, the
pancreas is around 5 inches long and divided into four sections: the head, neck, body,
and tail. The pancreas regulates blood sugar levels through insulin production and
secretes digestive juices and enzymes.
• Function: The pancreas regulates blood sugar levels through insulin production and
helps in digestion by secreting digestive juices and enzymes.
• Found in: The abdomen

17. PANCREAS
• The pancreas is an organ that in humans lies in the abdomen, stretching from
behind the stomach to the left upper abdomen near the spleen. In adults, it is about
12–15 centimetres (4.7–5.9 in) long, lobulated, and salmon-coloured in appearance
• Anatomically, the pancreas is divided into a head, neck, body, and tail. The pancreas
stretches from the inner curvature of the duodenum, where the head surrounds two
blood vessels: the superior mesenteric artery and vein. The longest part of the
pancreas, the body, stretches across behind the stomach, and the tail of the pancreas
ends adjacent to the spleen.

18. BLOOD SUPPLY
Arterial supply
• the coeliac artery
• superior mesenteric artery.
• The splenic artery,

19. FUNCTIONS
• The pancreas is involved in blood sugar control and metabolism within the body, and
also in the secretion of substances (collectively pancreatic juice) that help digestion.
These are divided into an "endocrine" role, relating to the secretion of insulin and
other substances within pancreatic islets that help control blood sugar levels and
metabolism within the body, and an "exocrine" role, relating to the secretion of
enzymes involved in digesting substances in the digestive tract.

20. BLOOD GLUCOSE REGULATION
• The pancreas maintains constant blood glucose levels. When the blood glucose level
is too high, the pancreas secretes insulin and when the level is too low, the pancreas
secretes glucagon.
• Cells within the pancreas help to maintain blood glucose levels (homeostasis). The
cells that do this are located within the pancreatic islets that are present throughout
the pancreas. When blood glucose levels are low, alpha cells secrete glucagon, which
increases blood glucose levels. When blood glucose levels are high beta cells secrete
insulin to decrease glucose in blood. Delta cells in the islet also secrete somatostatin
which decreases the release of insulin and glucagon

21. DIGESTIVE ROLE
• The pancreas plays a vital role in the digestive system. It does this by secreting a
fluid that contains digestive enzymes into the duodenum, the first part of the small
intestine that receives food from the stomach. These enzymes help to break down
carbohydrates, proteins and lipids (fats). This role is called the "exocrine" role of the
pancreas.

23. THYMUS
• The thymus is a small organ located under the sternum in the front (anterior) part
of the chest. The thymus has two lobes that are covered in a fibrous capsule. As a
part of the immune system, the thymus is composed of immature immune cells
called T cells that help the body recognize and ward off foreign invaders.
• Function: The thymus is a critical organ in the immune system, and helps the body
recognize and combat pathogens and foreign invaders.
• Found in: The chest

24. STRUCTURE
• The thymus is located in the anterior mediastinum. It is made up of two lobes that
meet in the upper midline, and stretch from below the thyroid in the neck to as low
as the cartilage of the fourth rib. The lobes are covered by a capsule.
• The thymus lies behind the sternum, rests on the pericardium, and is separated
from the aortic arch and great vessels by a layer of fascia.
• The left brachiocephalic vein may even be embedded within the thymus. In the neck,
it lies on the front and sides of the trachea, behind the sternohyoid and
sternothyroid muscles.

25. BLOOD AND NERVE SUPPLY
• Arterial
• the internal thoracic,
• inferior thyroid arteries,
Venous
• the thymic veins,
• left brachiocephalic vein,
• internal thoracic vein,
• inferior thyroid veins the vagus nerve

26. FUNCTIONS
• The thymus facilitates the maturation of T cells, an important part of the immune
system providing cell-mediated immunity.

28. THYROID
• The thyroid gland is a small, butterfly-shaped organ located in the neck, partly
wrapped around the trachea. The thyroid’s two “wings” are connected in the middle.
Functionally, the thyroid gland is an important endocrine gland that produces
thyroid hormone and calcitonin, which are involved in regulating the metabolism.
• Function: The thyroid gland is an important endocrine gland that produces thyroid
hormone and calcitonin, which are involved in regulating metabolism.
• Found in: The neck

29. • The thyroid gland is a butterfly-shaped organ composed of two lobes, left and right,
connected by a narrow tissue band, called an "isthmus". It weighs 25 grams in
adults, with each lobe being about 5 cm long, 3 cm wide, and 2 cm thick and the
isthmus about 1.25 cm in height and width

30. BLOOD SUPPLY
Arterial
• the superior thyroid artery, a branch of the external carotid artery, and the inferior thyroid artery,
Venous
• superior and middle thyroid veins,
• the prelaryngeal lymph nodes (located just above the isthmus) and the pretracheal and paratracheal
lymph nodes.
• the superior laryngeal nerve and the recurrent laryngeal nerve.