AP BIOLOGY

Detailed explanation-1: -ADH then acts primarily in the kidneys to increase water reabsorption, thus returning the osmolarity to baseline.

Detailed explanation-2: -Antidiuretic hormone binds to receptors on cells in the collecting ducts of the kidney and promotes reabsorption of water back into the circulation. In the absense of antidiuretic hormone, the collecting ducts are virtually impermiable to water, and it flows out as urine.

Detailed explanation-3: -For ADH, secretion is regulated by plasma osmolality. 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 producing concentrated urine.

Detailed explanation-4: -This hormone increases the reabsorption of water in the distal convoluted tubule and collecting duct by making them more permeable to water.

Detailed explanation-5: -ADH acts upon the collecting ducts and distal convoluted tubules of nephrons to increase water reabsorption. It causes an increase in the number of aquaporins in order to allow for this.