Presentation on pituitary gland

Sonam TsheringSamdrup Rinzin

Anatomy of pituitary glandIt is also called as hypophysis or master

gland because it controls /influences all other endocrine glands.

It forms a links between nervous and endocrine system.

Location- it is located at the base of the brain near to the optic nerves. It attach to the hypothalamus.

Structure- it is pea sized gland which weigh about 0.5 to 1 gram and 1-1.3 cm in diameter.

Based on the origin, the pituitary is further divided into two lobes-

Adenohypophysis/ anterior pituitary and Neurohypophysis/ posterior pituitary

Posterior pituitary- It develops from the ventricles and it

secretary cells are called as pituicytes. It secrete two hormones – 1)

Antidiuretic(ADH) and 2) Oxytocin or pitocin hormones.

Antidiuretic(ADH)It is the water retaining hormones.It stimulus the water reabsorption by distal

and collecting tubules and reduce the water loss in urine.

Hypo secretion of this hormones leads to diuresis( abnormally large urine volume) and cause diabetes insipidus.

Hyper secretion of this hormones leads to antidiuresis (small urine volume).

Oxytocine/ pitocinIt is also called as birth hormones.It contracts the uterine muscle during child

birth and ejection of the milk from breast during lactation.

Anterior pituitary It is connected with a hypothalamus by a portal

system of blood vessel.It secrete hormones which are either

polypeptides, proteins and glycoprotein's.

It secretory cells are of two types: 1) acidophils and 2) Basophils.

The acidophiles secrete somatotropin hormones(STH) and prolactin.

The basophile secrete TSH, FSH, LH and ACTH.Based on the functional significances these are

grouped into 1) tropic and 2) gonadotropins hormones.

Tropic hormones 1. Somatotropic hormones (STH)/ growth

hormones-It enhances the metabolic processes leading

to body growth.It increases proteins anabolism, fat

metabolism and increase glucose catabolism. It also enhances for cell division, growth of

muscles, bone s and connective tissue.Hypo secretion of STH cause following

diseases-A) Dwarfism- it is the diseases caused during

childhood stage.

B) Myxoedema- it is the diseases caused during adult stage (after growth period).

person with these diseases are weak with retarded physical growth and mental growth. Hands and legs are disproportionate. Immature sexuality and retarded sexual character.

Hyper secretion of STH- it cause the following diseases-

1) Gigantism- it caused during childhood stage It body will be healthy, long and giant sized person. 2) Acromegaly- it is the diseases in adult stage.

This hormones produces disproportionate gaints. These have ugly face because of the thickness of facial bones, long jaws and protruding forehead.

2- Thyroid stimulating hormones(TSH): It stimulates the thyroid gland to secrete

thyroxin.Its secretion is under controlled by

thyrotropin releasing factors(TRF) produced by hypothalamus.

Hypo secretion of TSH lead to fall blood level and as a results it cause the disease known as thyroid atrophy.

Hyper secretion of TSH lead to produce excess thyroxin.

3 Adreno cortico tropic hormones (ACTH): It controls the normal functioning of adrenal

glands and release of mineralo-corticoids and glucocorticoids.

2 Luteinizing hormones(LH) in female and interstitial cell in male-

Luteinizing hormones stimulates ovulation, formation of corpus luteum and secretion of progesterone's and estrogens from corpus luteum.

In male this hormones is called interstitial cell stimulating hormones. It stimulates the secretion of testosterones.

3 prolactin or lactogenic hormones-It controls the secretion of milk after delivery

and during pregnancy promotes breast development.

With LH it maintains corpus luteum late in post ovulatory or premenstrual phase.

Hypo secretion of ACTH cause atrophy of adrenal gland.

Hyper secretion of ACTH cause excessive growth of adrenal cortex.

2 Gonadtropins hormones-It controls the normal functioning of gonads

and accessory organs. These are:1 Follicle stimulating hormones(FSTH)-In female it stimulates the growth of graafian

follicle and secretion of estrogens by follicle cells .

In male it controls the formation of spermatozoa.

It secretion is under controlled by prolactin hormones releasing factor(PRF)

Intermediate lobe-It secretes one hormones known as

intermedin or melanocytes stimulating hormones (MSH).

It increases the pigmentation or darkening of the skins in many animals such as fish, amphibian but no role man.

References Rastogy, V. B. (2007).I.S.C Biology for Class

Xii. Vol II. Piyush printer publisher pvt. Ltd: New

Delhi.Retrieved on 25th of March from

http://www.answers.com/topic/graafian-follicle

Retrieved on 24th of March from http://www.umm.edu/endocrin/pitgland.htm