The endocrine system coordinates and regulates bodily functions through the secretion of hormones from various glands directly into the bloodstream. The major glands include the hypothalamus, pituitary, thyroid, parathyroids, adrenals, pancreas, testes, and ovaries. The hypothalamus controls the pituitary gland which secretes hormones that regulate other endocrine glands. Hormones maintain homeostasis, metabolism, sexual development, and reproduction. Glandular secretions are influenced by negative and positive feedback loops in the endocrine system.

1. CHEMICAL
COORDINATIO
N AND
INTEGRATION
CHEMICAL
COORDINATION
AND INTEGRATION

2. Endocrine glands lack
ducts and are called
ductless glands .Their
secretions are called
hormones.

3. HUMAN ENDOCRINE SYSTEM
Pituitary gland
Pineal gland
Thyroid gland
Adrenal gland
Pancreas
Parathyroid gland
It includes
Thymus gland and
Gonads

4. HYPOTHALAMUS
• It is the basal part of fore
brain
• The hormones produced
by it are of two types.
• Releasing hormone
&Inhibiting hormone.
• For example GnRH
stimulates the pituitary to
release gonadotropin&
somatostatin from
hypothalamus inhibits the
release of growth
hormone.

5. HYPOTHALAMUS AND PITUITARY
• Hypothalamic hormones
originating in the
hypothalamic neurons
passes through the axon
and reach the anterior
pituitary through portal
system.
• The posterior pituitary is
under the direct control
hypothalamic neuron.

6. PITUITARY GLAND
• It is located just below the
hypothalamus in a bony cavity
called Sella tursica.
• Anterior pituitary-
Adenohypophysis
• Posterior pituitary-
Neurohypophysis

7. ADENOHYPOPHYSIS (PARS DISTALIS)
• It secretes the following hormones
• Growth Hormone (GH)
• Prolactin(PRL)
• Thyroid Stimulating Hormone (TSH)
• Adrenocorticotrophic Hormone(ACTH)
• Luteinizing Hormone(LH)
• Follicle Stimulating Hormone(FSH)

8. ADENOHYPOPHYSIS (PARS
INTERMEDIA)
•It secretes only one
hormone called
melanocyte stimulating
hormone (MSH).

9. NEUROHYPOPHYSIS
•It stores and releases the
following hormones.
•Oxytocin
•Vasopressin

10. GROWTH HORMONE
• GH; Over secretion
leads to gigantism.
Low secretion leads to
pituitary dwarfism.

11. PINEAL GLAND
• It is located at the dorsal side of fore brain.
• It secretes melatonin.
• Melotonin regulates circadian rhythm.
• It maintains body temperature,metabolism and
pigmentation.

12. THYROID GLAND

13. THYROID HORMONES
•Follicular cells of thyroid secretes two
hormones.
•Triiodothyronin (T3) and
tetraiodothyronin(T4).
•Iodine is essential for normal
functioning of this gland.

14. HYPERTHYROIDISM
•It is the over secretion of
thyroid hormones due to
cancerous growth or nodule
development in the thyroid
gland.

15. HYPOTHYROIDISM
• Deficiency iodine in our diet results
in Hypothyroidism or Goitre.
• Symptoms;
• Stuntedgrowth(Cretinism),mental
retartation,low intelligence -
quotient,abnormal skin&deaf-
mutism.
• In women it causes menstrual
irregularities.

16. FUNCTIONS OF THYROID HORMONES
•It regulates the basic metabolism.
•Helps in RBC formation.
•Maintains ionic balance.
•Thyrocalcitonin regulates blood
calcium level.

17. PARATHYROID GLAND
• In human 4 parathyroid glands are
present.
• They are located on the back side of
the thyroid gland.
• It secretes Parathyroid hormone.
• It maintains calcium balance in our
body.

18. ADRENAL GLAND
• Our body has one
pair of adrenal
glands.
• It has an outer
cortex and an inner
medulla.

19. ADRENAL CORTEX
• Adrenal cortex is divided
into 3 regions .
• Outer-Zona reticularis
• Middle;Zona fasiculata
• Inner Zona glomerulosa

20. HORMONES OF ADRENAL
CORTEX
• Adrenal cortex secretes many hormones commonly called corticoids.
• Glucocorticoid;It is involved in carbohydrate
metabolism,lipolysis&proteolysis.
• It is also involved in maintaining cardio vascular system &kidney
functions.
• Cortisol produces anti inflammatoy reactions& suppresses the
immune responses.
• It stimulates the RBC production.
• Mineral corticoids maintain ionic balance in the body.
• Sex corticoids or androgenic corticoids play a role in the growth of
axial hair ,pubic hair and facial hair during puberty.

21. HORMONES OF ADRENAL MEDULLA
• It secretes two hormones namely adrenalin or epinephrine and
noradrenalin or norepinephrine.
• These are commonly called as catecholamines.
• These hormones are secreted in response to stress of any kind and
during emergency situation and are called emergency hormones
or hormones of fight.

22. PANCREAS
• It is a composite gland.
• It is both endocrine and exocrine in
nature.
• I t has islets of langerhans.Islets of
langerhans has 2 types of cells/
• They are alpha cells and beta cells.
• Alpha cells secrete a hormone called
glucagon,while beta cells secrete a
hormone called insulin.

23. GLUCAGON
• It is a peptide hormone
• It plays an important role in maintaining
blood glucose level.
• It stimulates glycogenolysis and increase
the blood glucose level (hyperglycemia).
• It is a hyperglycemic hormone.

24. INSULIN
• It is also a peptide hormone.
• It enhances cellular glucose uptake and utilisation.So
there is a rapid movement of glucose from blood to
hepatocytes and adipocytes resulting in decreased blood
glucose level.
• It also stimulates the conversion of glucose to glycogen.
• It is a hypoglycemic hormone.
• Insulin deficiency leads to diabetes mellitus

25. TESTES
• A pair of testis is present in the scrotal sac of male individuals.
• It performs dual functions.
• I t is a primary sex organ as well as an endocrine gland..
• It has seminiferous tubules and interstitial tissue.
• Interstitial cells secrete androgen or testosterone.
• This hormone is responsible for the development of secondary
sexual characters in male.
• It also produces anabolic effects on protein and carbohydrate
metabolism.

26. OVARY
• A pair of ovaries are located in the abdomen of female.
• It is a primary sex organ.
• It also produces 2 hormones called estrogen and progesterone
• Estrogen is produced by ovarian follicles.
• It is responsible for the development of secondary sexual characteristic
features in female.
• After ovulation the ruptured follicle is converted into a structure called corpus
luteum.
• It secretes progesterone
• Progesterone supports pregnancy.

27. THYMUS GLAND
• It is located on the dorsal side of heart and
aorta.
• It secretes thymosins.
• I t helps in the production of T –Lymphocytes
and antibodies.
• It is degenerated in old individuals as a result
the immune responses of old persons become
weak.

28. HORMONES OF HEART ,KIDNEYAND
GASTROINTESTINAL TRACT
• Atrial wall of heart secretes ANF.It reduces the blood pressure.
• Juxtaglomerular cells of kidney produces erythropoietin which
stimulates RBC formation.
• Gastrointestinal tract secretes 4 hormones namely
gastrin,secretin.cholecystokinin(CCK)&gastric inhibitory peptide
(GIP).
• Gastrin-HCL & pepsinogen
• Secretin –water &bicarbonates
• CCK-Pancreatic enzymes &bile juice.
• GIP-inhibits gastric secretion and mobility.

29. MECHANISM OF HORMONE ACTION

30. MECHAINSM OF HORMONAL ACTION (INTRA CELLULAR
RECEPTOR)

31. TYPES OF HORMONES
• On the basis of their chemical nature, hormones
can be divided into 4 groups.
• Peptide hormones (insulin & glucagon)
• Steroidal hormones (Estrogen,progesterone,
testosterone & cortisol)
• Iodothyronines(Thyroid hormones)
• Amino acid derivatives (Epinephrine)