Pituitary glands
- The pituitary or master gland acts as a regulating unit of the activity of most of the other endocrine glands. It is the most protected gland and lies in a bony cavity called as hypophysial fossa or shell turcica of besiphenoid bone. This gland is attached to hypothalamus by infundibulum.
- The gland consists of two parts: adenohypophysis and neurohypophysis.
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01 Hormones secreted by adenohypophysis
The adenohypophysis is formed of two lobes i.e. anterior and intermediate lobe. These both lobes are formed by embryonic buccal cavity ( Rathke’s pouch). Adenohypophysis contains three types of cells. These are basophils acidophils, chromophils.
- Growth Hormone or Somatotropin Hormone ( GH or STH)
- It stimulates body growth, protein and fat and carbohydrate metabolism
- Hyposecretion of this hormone causes dwarfism during the skeletal growth period.
- Hypersecretion of this hormone during the period of skeletal growth causes gigantism characterized by excessive growth of bones, with the enlargement of internal organs as well.
- Hypersecretion in adulthood causes acromegaly. Here, the bones becomes abnormally thick due to ossification of periosteum and thickening of soft tissues as well.
- FSH or Follicle Stimulating Hormone.
- It is produced by the basophilic cells, along with galactose mannose etc.
- Function: In females growth of ovarian follicles up to ovulation
In males Development of seminiferous tuble and maintenance of spermatogenesis.
- LutenizingHormone or interstitial cell stimulating hormone ( LH or ICSH)
It is produced by basophilic cells. The hormone stimulates the testis to secrete the male sex hormones, testosterone and the corpus luteum in ovaries to secrete female sex hormones called progesterone.
- Prolactin
It is produced by acidophilc cells. This hormone stimulates lactation ( milk production) and has a direct effect on the breasts immediately after parturition.
- Adrenocorticotropic Hormone
- It is secreted by the corticotropic cells of anterior pituitary.
- It stimulates the flow of blood to the adrenal cortex, increases the concentration of cholesterol and steroids within the gland and increases the output of steroid hormones, especially cortisol.
- Hyposecretion causes acute psoriasis and dermatitis ( the diseases of skin)
- Its hypersecretion causes cushing’s disease characterized by obesity, skin pigmentation increases, excessive hair, demineralization of bone and loss of sexual function.
- Thyroid stimulating hormone or TSH
It is secreted by special basophilic cells. The hormone promotes growth and function of thyroid gland. It secretion is stimulated by a hypothalamic thyrotropin release factor (TRF)
- Lipotropin Hormone
It is in the form of a complex with I, II and β-Lipotropins. It stimulates fatty acid liberation from adipose tissue. Hyposecretion causes obesity and hypersecretion causes thickness
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