AP BIOLOGY

Detailed explanation-1: -ADH makes the collecting ducts more permeable to water so that more water is reabsorbed. As a result, a small volume of concentrated urine is produced. ADH acts on aquaporin-2, a membrane protein that forms gated water channels in the wall of the collecting ducts.

Detailed explanation-2: -ADH is released by the pituitary gland when the blood is too concentrated and it causes the kidney tubules to become more permeable . This allows more water to be reabsorbed back into the blood during selective reabsorption.

Detailed explanation-3: -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-4: -ADH increases the permeability to water of the distal convoluted tubule and collecting duct, which are normally impermeable to water. This effect causes increased water reabsorption and retention and decreases the volume of urine produced relative to its ion content.

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.