PITUITARY GLAND (HYPOPHYSIS)

-Origin - Ectodern 
-Locaton- Situatw in a cavity sella tursica and atlach to the hypothalamus by  a stalk called infundibulum. 
-Size-Pea sized pear shaped and one of the smallest endocine gland.

-Structure -   Anatonically it has two parts 

(a)Adenohypophysis                    (b) Neurohypophysis.

(a)Adenohypophysis or anterior pituitary- It is also called divided  into two pars as pars distalis and  pars  intermedia.
-Pars distalis commonly called anterior pituitary.
-It produces following hormones.

Growth hormone (GH)or somatotropin or Human growth hormone (HGH)

-This hormone brings about the  growth in bones and muscle of the  body.
- It induces liver to produce somatomedins also called insulin like growth factor  operates through it.
-Hypersecreteon causses gigantism and acromegaly.
-Hyposecretion causes dwarfism and acromicria.
Prolactin or Lectogenic or Luteotrophic hormone-
-This protein hormone causes developoment of mammary glands during prognancy and milk production (lactation ) after child birth. 
Thyroid stimulateng hormone (TSH) -This protein hormone stimulates thyroid gland for the synthesis and secretion of thyroid hormone form thyroid gland. 
Adrenocorticotrophic hormone (ACTH) -This peptide hormone stimulates the synthesis and secretion of steroid  hormone stimulates the synthesis and  secretion of steroid hormone (Glucocorticoids) from adrenal cortex.
Follicle stimulating hormone (FSH)-It is a protein hormone.
Function in males- This gonadotrophin or FSH together with androgens regulate spermatopenesis.
Function in females-It stimulates growth and development of ovarian follicle.
Luteinising hormone(LH) or Interstitial cell stimulating hormone(ICSH)-
Function of LH in  femaies- It brings about  ovulation from mature graffian follicle and maintains the function of corpus luteum.
Function of ICSH in males-  It activates leydig cells (Inter stitial cell) of testis to secrete androgens as testosteron. 

-In human pars intermedia is almost merged with adenohypophysis.
-It produces a peptide hormone which stimulates the melanocytes(melanin containing cell) and regulate pigmentation of the skin.
Neurohypophysis or posterior pituitory or pars nervosa-
-This part of pituitory stores and releases oxytosin and vasopressin which after synthesis in neurons of hypothalamus transported to neurohyposis by its axon.
Oxytosin or pitocin or birth hormone- It acts on smooth muscle in both male and female.
-In female it stimulates strong contraction of uterus at the time of child birth and also bring about milk ejection from mammary gland by contracting myoepithelial cells.
-Sucking of nipples by baby stimulates the secretion of oxytocin.
-Sight and sound of baby cause production of oxytocin in lactating mothers.
-Widening of uterus during child birth also causes release of oxytocin.

Vesopressin or ADH(anti-diuretic hormone)-

-It acts upon kidney and stimulates resorption of water and electrolytes from DCT(distal convulated tubules) and collecting tubules.
-So it reduces loss of water through urine or diuresis.
-Reduced secretion of ADH causes diabetes insipidus.