What hormones are secreted by the posterior pituitary gland ? What function does each serve? Where are these hormones actually produced ? How are these hormones transported to the region from which they are released ?
(at) Oxytocin : It is released into the blood when hypothalamic neurons are stimulated by the widening of uterus at the time of delivery or by the sucking of breasts by an infant. It induces contraction of smooth muscles of the uterus during the birth of a young one and myoepithelial cells of mammary glands to cause release of milk during sucking by an infant. Therefore, it is also known as ‘birth hormones’ and or ‘milk-ejecting hormones’,
(b) Vasopressin : It is also called antidiuretic hormone (ADH). It decreases the loss of water in urine by increasing reabsorption of water in distal convoluted tubules, collecting tubules and collecting ducts of kidneys. It is transported as neurophysin - proteins bond secretary granules down the nerve fibre.