Question

explain the interplay between the hypothalamus, pituitary gland and target tissue. please give specific examples.

Answer 1

Hypothalamus and pituitary gland :-
• Hypothalamus controls the hormone secretion of pituitary gland.
• Hypothalamus releases two types of hormones - releasing and inhibiting. These hormones regulates hormone secretion by anterior pituitary gland.
• Releasing hormones increases hormone release and inhibiting hormones inhibits hormone secretion by pituitary gland
• Hormones of hypothalamus are released via hypothalamic-hypophyseal portal veins to anterior pituitary gland.

Pituitary and other glands :-
• Pituitary gland is master gland of endocrine system and regulates other parts of endocrine system.
• Pituitary hormones have direct effect on body tissue or stimulates other glands to secrete hormones.

Example :-
HPA/ Hypothalamus pituitary adrenal axis :-
• Hypothalamus regulates secretion of pituitary gland and pituitary stimulates hormone secretion by adrenal gland.
• Hypothalamus secrets Corticotropin-releasing hormone (CRH) and gives signals to pituitary gland for hormone secretion.
• Now, pituitary gland secretes Adrenocorticotropic hormone (ACTH) and stimulates adrenal gland for hormone secretion. In response of this, adrenal gland secretes cortisol, which regulates metabolic processes of body.
• In excess cortisol, this cortisol hormone gives negative feedback to pituitary and hypothalamus gland and these glands inhibit the secretion of this hormone.