Friday, 14 October 2016

PITUITARY GLAND

*it is the smallest endocrine gland.
*it  was termed by Andrew Vesalius.
*it has pin head like shape




*pituitary gland contains mainly two parts-
Adenohypophysis
Neurohypophysis.

*in female,it helps in ovulation.
*it helps in growth and development of Corpus Luteum and other endocrine gland.
*Corpus Luteum secretes progesterone(female sex hormone)
*it helps in growth and maintenance of uterus and implanted embryo, and also helps in growth of secondary sexual character. Viz- enlargement of breast, growth of pubical hair, deposition of fat in buttock.

LUTEOTROPHIC HORMONE / LTH / PROLACTIN HORMONE-

  • it is secreted from Pars distalis of Adenohypophysis.
  • it has no role in male.
  • in female it helps in growth and development of breast and synthesis of milk after four months of pregnancy.
MELANOCYTE STIMULATING HORMONE / MSH-
  • it is secreted from pars intermedia of Adenohypophysis.
  • it helps in synthesis of melanin pigment in other vertebrate except birds and mammals.
  • in birds and mammal ,function is still unknown.
OXYTOCIN / PITOCIN-
  • it is secreted from pars nervosa of neurohyposis.
  • it is nonapeptide in structure.
  • it is neurohormone.
  • in male it has no role.
  • in female it helps in contraction and relaxation of vagina during parturition
  • it helps in ejection of milk so called as milk ejecting hormone.
ANTIDIURETIC HORMONE / ADH / VASOPRESSIN / PITRESSIN
  • it is secreted from pars nervosa of neurohypophysis
  • it incresace the permeability of wall of DCT to increase reabsorption of water.
  • hyposecretion of ADH may cause Diabetes insipidus , which is insuline dependant diabetes.
*Hormone of hypothallamus control pituitary gland.
*hypothallamus secretes two types of factor i.e.- release factor and inhibitory factor.
*release factor stimulate release of particular hormone and inhibitory factor inhibit some particualr type of hormone as per requirement.

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