What is Pituitary Gland?

Pituitary gland is an endocrine gland The gland is enclosed by diameter and lies in the Sella turcica of the sphenoid bone. The pituitary gland has two primary lobes or division’s anterior and posterior lobe which have different mode of developments, structure and different function. Both are under the control of hypothalamus but by different Mechanism Anterior pituitary or lobes is called adenohypophysis because of its glandular nature. It is delivered from the mouth and nasal cavity. The posterior pituitary or lobes is an outgrowth of the hypothalamus. Thus it is called neurohypophysis which is derived from the brain.

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The pitu­itary gland pro­duces many hor­mone. The hor­mones dom­i­nate the activ­i­ties of the brain thy­roid gland, all the sec­re­tary activ­i­ty of the pitu­itary is con­trolled by a small area of the brain known as the hypo­thal­a­mus. In response to var­i­ous mes­sage com­ing from the inter­nal and exter­nal envi­ron­ment, the hypo­thal­a­mus sends sin­gal down the pitu­itary slack and orders appro­pri­ate changes in the sec­re­tary activ­i­ty of ante­ri­or lobe and the dis­charge of steroid hor­mone by the pos­te­ri­or lobe of the pitu­itary gland.

Hormones of the Anterior pituitary / adenohypophysis

It secrets num­ber of hor­mones of they are col­lec­tive­ly known as trop­ic hor­mones since they reg­u­late the growth and activ­i­ty of the body as whole or oth­er endocrine glands.

1. Growth Hor­mone — It is respon­si­ble for the growth of bones , mus­cle and organs.Disorder relat­ed to the GH

Gigan­tism — it rare con­di­tion that caus­es abnor­mal growth in chil­dren occured by excess amount of GH.

Acromegaly — It devel­ops when pitu­itary gland pro­duces too much growth hor­mone dur­ing Adulthood.

Dwarfism — It occurs when the pitu­itary gland fails to pro­duce an ade­quate sup­ply of growth hormone.

2. Adreno­cor­ti­cotrop­ic Hor­mone - It reg­u­lates lev­els of the cor­ti­sol hor­mone , which released from Adren­al gland which acts to main­tain BP , Blood ‚Sug­ar lev­el etc
3. Luteinz­ing Hor­mone — It con­trol the func­tion of ovaries in female for ovu­la­tion and for­ma­tion of cor­pus luteum
4. Fol­li­cle Stim­u­lat­ing Hor­mone — It stim­u­late the growth in female ovar­i­an fol­li­cle and in male it stim­u­lates Sperm production.

Hormones Secreted By Posterior lobe:

1. Antid­i­uret­ic Hor­mone (ADH)/ vaso­pressin — It plays a key role in main­tain­ing the con­cen­tra­tion of dis­solved par­ti­cles such as salts and glu­cose in the serum and there­fore in main­tain­ing the vol­ume of water in the body. It con­strict blood ves­sels also main­tains Bp Dis­or­der relat­ed to ADH :-
   • Dia­betes Insipidus - It is caused by a lack of ADH. The symp­toms are extreme thirst, pro­duc­ing large amount of dilut­ed urine fre­quent uri­nate dur­ing night & pref­er­ence for cold drinks.
   • Polyuria — it is marked by a decreased in either the pro­duc­tion on release of ADH . in this Con­di­tion exces­sive pro­duc­tion or pas­sage of urine ( greater than 2.5 — 3 L over 24 hrs in adults)

2. Oxy­tocin - It acts on organ the breast and uterus .
   • It stim­u­lates uter­ine mus­cle to con­tract and also increase pro­duc­tion of prostaglandin. It leads to the Milk ejection.
   • It stim­u­lates the mus­cle sur­round­ing the breast to squeeze out the milk

Hormone Secreted by Intermediate lobe :-

• Melanocyte Stim­u­lat­ing Hor­mone (MSH) :-

This hor­mone has cer­tain effect on mela­nine gran­ules in pig­ment­ed skin . It plays a role in pig­men­ta­tion in men. Both ACTH and MSH cause increase pig­men­ta­tion of the skin under cer­tain circumstances.