Dr. Waqas Nawaz PMAS arid agriculture university rawalpindi

1. Endocrine Glands
Waqas Nawaz
11-arid-975
Group A-1

2. Endocrine Glands:
Endocrine glands are ductless organs that secrete
special substances termed HORMONES.
These hormones are released into circulatory system
and transported to distant receptor organ.
Hormones are produced by parenchymal cells,which
can be found as single,aggregate or organized as
endocrine glands.

3. Glands of Endocrine System:
Pituitary Gland
Pineal Gland
Thyroid Gland
Parathyroid Glands
Adrenal Gland
Pancreas
Gonads

4. Pituitary Gland
Called “Master gland” of the body.
Plays major regulatory role in entire endocrine
system.

5. Location:
Situated at the base of skull.
Suspended below diencephalon,in the hypophyseal
fossa of sphenoid bone.
Connected to hypothalamus by pituitary stalk.

6. Morphology:
Pituitary gland is an un-paired organ.
Has size only of pea.

7. Anatomy of Pituitary Gland:
Anatomically pituitary gland is made up of following 3
parts……..
Adenohypophysis (anterior pituitary)
Neurohypophysis (posterior pituitary)
Intermediate lobe

8. Adenohypophysis:
Consists of endocrine cells, numerous blood vessels
& very few nerve fibers.
The pituitary stalk contains a special portal
system,organised in same manner as portal venous
system in liver,with two capillary networks following
each other.

9. Blood supply to
adenohypophysis:
Vessels from first capillary network convey blood to
anterior pituitary.
While second capillary system surrounds the hormone
producing cells.

10. Hormones of adenohypophysis:
Hormone Effect
Somatotropin Growth via secretion of IGF-I
Thyroid stimulatin hormone (TSH) Secretion of thyroid hormone
Adenocorticotopic Hormone (ACTH) Secretion of glucocorticoids and androgens
Prolactin (PRL) Production of milk
Gonadotropin:- Production and maturation of spermatozoa
Follicle stimulating hormone (FSH) and oocyte.
Luteinzing hormone (LH) Secretion of sex hormone

11. Neurohypophysis:
Second part of pituitary gland.
It is a part of central nervous system.

12. Location:
Located caudal to adenohypophysis.
It is a neural outgrowth of hypothlamus.

13. Anatomy of neurohypophysis:
It consists of a stalk which connects the pituitary
gland to tuber cinereum of hypothalamus and
distal,major part of neurohypophysis.

14. Mode of secretion:
Contains no hormone producing cells.
Instead the hormones are secreted by the neurons
which have their cell bodies into hypothalamus.
Because the posterior pituitary hormones are
produced in hypothalamus.
So it is not entirely accurate to call posterior as
endocrine gland,rather it acts as hormone storage
store.

15. Conti……..
Neurohypophysis stores and releases hormones
produced by the neurosecretory cells of supraoptic
and paraventricular nuclei of hypothalamus.

16. Conti..

17. Hormones of posterior pituitary:
Hormone Effect
Oxytocin Elicit milk let down
Increase uterine
contractions
Antideuratic Hormone Reabsorption of water
in kidneys

18. Hormones of both lobes:

19. Intermediate lobe:
The portion of adenohypophysis, in direct contact
with distal part of neurohypophysis is termed as
intermediate lobe.
Intermediate lobe is present between two major
parts of pituitary gland, which thing gives it its name.
During embryonic development intermediate lobe
develops from epithelial tissue.

20. Anatomy of intermediate lobe:
Intermediate lobe extends around neurohypophysis
and the anterior lobe is separated from the
intermediate lobe by the hypophyseal cleft which is
also known as cavum hypophysis.

21. Hormones of intermd. lobe:
The intermediate lobe of pituitary gland produces
melanocyte stimulating hormone.
Which regulates the skin colour.
This hormone regulates the skin colour only in lower
vertebrates but the function of this hormone is not
known in mammals and birds, although it is secreted.