endocrine

1. English for master student
Dept. of Animal Production
Zahraa

2. ENDOCRINE SYSTEM
• Endocrine tissue is made up of cells that release
chemicals directly into the bloodstream.
• Some organs are entirely endocrine in function.
They are referred to as endocrine glands like
pituitary glands, pineal body, thyroid gland,
parathyroid glands, and adrenal glands.

3. • Groups of endocrine cells may be present in
organs that have other functions like islets of the
pancreas, the interstitial cells of the testes, the
kidneys, and the follicles and corpora lutea of
ovaries.
• The function of the endocrine system is the
production and regulation of chemical substances
called hormones.
ENDOCRINE SYSTEM
(CONTINUED)

4. • Hormones travel through the blood to target cells.
• Some hormones act only on one organ or on one
type of cell, while other hormones may have
widespread effects.
• The endocrine organs coordinate and control the
metabolic activities and the internal environment of
the body.
ENDOCRINE SYSTEM
(CONTINUED)

5. • A gland is an organ that produces a secretion.
• Endocrine glands: are organized groups of tissues
which use materials from the blood to make new
compounds. Endocrine glands are also called
glands of internal secretion.
GLANDS

6. •A hormone is a chemical transmitter. It is released in
small amounts from glands and is transported in the
bloodstream to target organs or other cells.
•Hormones are chemical messengers, transferring
information and instructions from one set of cells to
another.
HORMONES

7. •Hormones regulate growth, development, mood,
tissue function, metabolism, and sexual function.
•Hyposecretion or hypersecretion of any hormone
can be harmful to the body. Controlling the
production of hormones can treat many hormonal
disorders in the body.
•Two types: peptides (proteins) and steroids (lipids).
HORMONES (CONTINUED)

8. •Peptide hormones do not enter the cell directly. These
hormones bind to receptor proteins in the cell
membrane.
•When the hormone binds with the receptor protein, a
secondary messenger molecule initiates the cell
response.
•Because peptide hormones are water soluble, they
often produce fast responses.
PEPTIDE HORMONES

9. •Steroid hormones enter through the cell membrane
and bind to receptors inside the target cell.
•These hormones may directly stimulate the
transcription of genes to make specific proteins.
•Because steroids work by triggering gene activity,
the response is slower than peptide hormones.
STEROID HORMONES

10. • Internal control of the body is directed by 2 systems:
1. The Nervous System
2. The Endocrine System
•The endocrine system and nervous system work
together to help maintain homeostatic balance. The
hypothalamus is a collection of specialized cells in the
brain and is the primary link between the two
systems. It produces chemicals that either stimulate or
suppress hormone secretions of the pituitary gland.
CONTROL OF THE BODY

11. •Hypothalamus
•Pituitary gland
•Thyroid
•parathyroid glands
•Thymus gland
•Adrenal glands
•Pancreas
•Reproductive glands
THE ENDOCRINE GLANDS
INCLUDE :

12. • Hypothalamus: It is a collection of specialized cells that are
located in the lower central part of the brain. It has a small,
cone-shaped structure which projects downward ending in the
pituitary stalk.
• Pituitary Glands: It is a little bigger than a pea and is nestled
in a bony depression below the underside of the brain. The
pituitary gland is divided into two major lobes, the anterior
lobe and the posterior lobe.
• Thyroid Gland: It is shaped like a bow tie or butterfly with two
lateral lobes that are connected by a narrow section called the
isthmus.
STRUCTURES

13. • Parathyroid Glands: They are two small, oval-shaped
glands, the cells that synthesize and secrete parathyroid
hormone are arranged in rather dense cords or nests around
abundant capillaries.
• Pancreas: It is an elongated organ that contains both
exocrine and endocrine tissues.
• Adrenal Glands: They are small, triangular glands made of
two parts: the outer region is called the adrenal cortex and
the inner region is called the adrenal medulla.
STRUCTURES (CONTINUED)

14. • Pineal Glands: The pineal body is made up of lobular
parenchyma of pinealocytes surrounded by connective
tissue spaces. The gland's surface is covered by a pial
capsule.
• Reproductive Glands: The female ovaries are oval-shaped
and roughly the size of an almond. It is attached to the
fimbria of the fallopian tube. The testes are oval organs
about the size of large olives that lie in the scrotum,
secured at either end by a structure called the spermatic
cord.
STRUCTURES (CONTINUED)

15. • Hypothalamus: Located below the thalamus at the center of the
brain, posterior to the optic chiasma.
• Posterior Pituitary Gland: Located at the base of the
hypothalamus.
• Anterior Pituitary Gland: Situated at the base of the brain.
• Thyroid Gland: Located in front of the neck below the larynx.
• Parathyroid Glands: Located adjacent to the two thyroid gland
lobes in the neck.
LOCATIONS

16. • Pancreas: Located in the middle of the upper stomach.
• Adrenal Gland: Located on top of both kidneys.
• Pineal Gland: Attached to the posterior wall of the third
ventricle.
• Ovaries: The female gonads, the ovaries, are located in the
pelvis.
• Testes: Located in the scrotum.
LOCATIONS (CONTINUED)

17. • Hypothalamus - The main function of the hypothalamus is
homeostasis. Nerve cells in the hypothalamus control the
pituitary gland by producing chemicals that either stimulate or
suppress hormone secretions from the pituitary.
• Posterior Pituitary Gland - It is responsible for a function of
the pituitary gland which releases the oxytocin hormone. This
hormone is required after distension of the cervix and the
vagina during labor.
FUNCTIONS

18. • Anterior Pituitary Gland - Secretes peptide hormones that act
on target organs including the adrenal gland, liver, bone,
thyroid gland, and gonads.
• Parathyroid - Releases parathyroid hormone, which regulates
the level of calcium in the blood with the help of calcitonin,
which is produced in the thyroid.
• Pancreas - The pancreas contains enzyme producing cells that
secrete two hormones. The two hormones are insulin and
glucagon. Insulin and glucagon are secreted directly into the
bloodstream, and together, they regulate the level of glucose in
the blood.
FUNCTIONS (CONTINUED)

19. • Adrenal Gland - Produces hormones that regulate body
functions. The medulla produces norepinephrine and
epinephrine, which regulate the body's reaction to stressful
events. The cortex produces several hormones that affect blood
pressure and blood sugar levels, growth, as well as some
sexual characteristics.
• Pineal Gland - Secretes melatonin, a hormone that may help
regulate the wake-sleep cycle.
FUNCTIONS (CONTINUED)

20. • Ovaries - Produce eggs and secrete the female hormones
estrogen and progesterone.
• Testes - Secretes hormones called androgens, these hormones
regulate body changes associated with sexual development.
FUNCTIONS (CONTINUED)