Question

Why does inhibition of ADH result in increased serum osmolarity?

Answer 1

The kidneys help regulate blood volume by increasing or decreasing the amount of urine produced. If plasma osmolality increases, it stimulates secretion of ADH, which acts at the collecting duct of the nephron where it causes reabsorption of only water and produces concentrated urine. If a person is dehydrated there is a Increase in plasma osmolarity, which causes a Increase in ADH production stimulating the kidneys to reabsorb water from the filtrate.

The kidney nephron collecting ducts are targeted by ADH and it is the reabsorption of water from the urine by increasing the permeability of water in the walls of the ducts. The stimulus for ADH secretion is increased, by an increase in the osmolarity of blood plasma. The ADH secretion is mainly increased in the conditions of dehydration and after eating salty foods. In the hypothalamus osmoreceptors can detect the increased osmolarity and stimulate the release of ADH. So the inhibition of ADH result in increased serum osmolarity.