11th Class Biology Chemical Coordination (Endocrine System) Hypothalamus    

Hypothalamus    

Category : 11th Class

Position and Structure : Hypothalamus is the floor of diencephalon. It is formed of masses of grey matter, called hypothalmic nuclei, containing neurosecretory cells. It is connected with anterior pituitary lobe by blood capillaries of hypophyseal portal system and with the posterior pituitary lobe by axons of its neurons, both passing through the pituitary stalk.

Hormones of hypothalamus : Neurosecretory cells of hypothalamus secrete neurohormones called releasing factors (RF) or inhibiting factors (IF). These neurohormones are carried by hypophyseal portal system to adenohypophysis (primary target organ) and stimulate or inhibit the release of trophic hormones from adenohypophysis. These neurohormones are proteinous in nature and formed of \[320\] amino acids.

 

Neurohormones of Hypothalamus

S.No.

Neurohormones

Physiological effects

1.

TRH (Thyroid Releasing Hormone - Releasing Factor)

Increased TSH secretion from adenohypophysis.

2.

ACTH-RF (Adrenocorticotrophic Hormone-Releasing Factor)

Increased ACTH secretion from adenohypophysis.

3.

STH-RF

 

 

(Somatotrophic Hormone-Releasing Factor)

Increased STH secretion from adenohypophysis

4.

SOMATOSTATIN (GROWTH INHIBITING HORMONE)

Decreased STH secretion from adenohypophysis.

5.

GTH-RF (Gonadotrophic Hormone-Releasing Factor)

(i) FSH-RF (Follicular Stimulating Hormone-Releasing Factor)

(ii) LH-RH (In female)

(Luteinising Hormone - Releasing Factor)

or ICSH-RF (In male)

(Interstitial Cells stimulating Hormone-Releasing Factor)

 

Increased FSH secretion from adenohypophysis.

 

Increased LH secretion from adenohypophysis.

6.

Prolactin-Releasing hormone (P-RH)

Increased secretion of prolactin or leuteotrophic hormone.

7.

Prolactin-Inhibiting hormone (P-IH)

Decreased secretion of prolactin or leuteotrophic hormone.

8.

MSH-RF (Melanophore Stimulating Hormone-Releasing Factor)

Increased MSH secretion from intermediate pituitary lobe.

9.

MIF (Melanophore Inhibiting Factor)

Decreased MSH secretion from intermediate pituitary lobe.

 

Hypothalamo – pituitary complex : Pituitary gland is closely related with hypothalamus. Both together form hypothalamo-pituitary complex.

The hypothalmic-pituitary (hypothalamo-hypophyseal) system is a direct proof of coordination between the hormonal and nervous system. It regulates most of the physiological activities of body and maintains homeostasis inside the body. These neurosecretory cells are known to synthesize two more hormones : Oxytocin and Vasopressin, which are stored in their axons extending in the posterior lobe of pituitary gland.

You need to login to perform this action.
You will be redirected in 3 sec spinner

Free
Videos