Presentation on pituitary gland Sonam Tshering Samdrup Rinzin

Anatomy of pituitary gland It 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/ pitocin It 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 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- 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