NEET BIOLOGY

Detailed explanation-1: -ADH increases water and urea permeability of the distal nephron, leading to excretion of a small volume of concentrated urine, thereby minimizing further loss of blood volume and decreasing the osmolarity of the plasma back toward normal.

Detailed explanation-2: -Specifically, ADH causes the collecting tubules to increase their resorption of water from the developing urine, thereby returning water to the circulatory system. The additional water serves to dilute the blood, causing the blood osmolarity to be decreased. Consequently, however, the urine becomes more concentrated.

Detailed explanation-3: -Antidiuretic hormone stimulates water reabsorbtion by stimulating insertion of “water channels” or aquaporins into the membranes of kidney tubules. These channels transport solute-free water through tubular cells and back into blood, leading to a decrease in plasma osmolarity and an increase osmolarity of urine.

Detailed explanation-4: -Dehydration causes the hypothalamus to release ADH (antidiuretic hormone) via the posterior pituitary gland. The ADH signal tells the kidneys to recover water from urine, which dilutes the blood plasma.