Question

Describe Adenohypophysis?

Answer 1

The pituitary gland is a pinkish pea-sized gland, about 1.3 cm in diameter and weighing only 0.5 g. It is located in a bony cavity called sella turcica of the sphenoid bone of the skull, and by a stalk, it is attached to the hypothalamus called the infundibulum. The pituitary is divided anatomically into an adenohypophysis and a neurohypophysis.

Complete answer:
An anterior lobe of the pituitary gland is the Adenohypophysis. It consists of two parts – pars distalis (anterior lobe of the pituitary) and para intermedia (intermediate lobe of the pituitary). The anterior lobe of the pituitary secretes five types of hormones that help in controlling the activity of other endocrine glands and most of the hormones are called trophic hormones.

I) Growth Hormone or Somatotropic Hormone or Somatotropin – This stimulates the growth of the body cells especially of bones of limbs and muscles by stimulating protein synthesis, absorption of calcium and converting glycogen to glucose.
II) Thyroid Stimulating Hormone or Thyrotropin – This stimulates the growth of the thyroid gland and secretion of thyroid hormones.
III) Adrenocorticotropic Hormone or Adrenocorticotropin – This stimulates the growth of the adrenal cortex and secretion of its hormones.
IV) Prolactin or Luteotropic Hormone – That stimulates the growth of breasts during pregnancy and lactation after childbirth. It is also called the hormone of maternity.
V) Gonad Stimulating Hormones or Gonadotropins – It is of two types – Follicle Stimulating Hormone and Luteinising Hormone.

Note: The intermediate lobe of the pituitary gland secretes a hormone named Melanocyte Stimulating Hormone (MSH). It stimulates the synthesis of black pigment melanin and also causes the dispersal of pigment granules in the pigment cells, thereby darkening the colour of certain animals like fishes and amphibians. It is also believed to be associated with the growth and development of melanocytes in man which give colour to the skin.