Why ADH is important in excretion
Answers
The anti-diuretic hormone acts to maintain blood pressure, blood volume, and tissue water content by controlling the amount of water and hence the concentration of urine excreted by the kidney. The principal action of ADH is to regulate the amount of water excreted by the kidneys. As ADH (which is also known as vasopressin) causes direct water reabsorption from the kidney tubules, salts and wastes are concentrated in what will eventually be excreted as urine. ADH travels in the bloodstream to the kidneys. Remember that in this setting ADH secretion will increase to conserve water, thus complementing the effect of low aldosterone levels to decrease the osmolarity of bodily fluids. The net effect on urine excretion is a decrease in the amount of urine excreted, with an increase in the osmolarity of the urine. ADH increases the permeability to water of the distal convoluted tubule and collecting duct, which is normally impermeable to water. This effect causes increased water reabsorption and retention and decreases the volume of urine produced relative to its ion content.