EVERYDAY SCIENCE

Detailed explanation-1: -Antidiuretic hormone (ADH) is a chemical produced in the brain that causes the kidneys to release less water, decreasing the amount of urine produced. A high ADH level causes the body to produce less urine.

Detailed explanation-2: -ADH then acts primarily in the kidneys to increase water reabsorption, thus returning the osmolarity to baseline.

Detailed explanation-3: -Water excretion by the kidney is regulated by the peptide hormone vasopressin. Vasopressin increases the water permeability of the renal collecting duct cells, allowing more water to be reabsorbed from collecting duct urine to blood.

Detailed explanation-4: -ADH primarily affects the ability of the kidney to reabsorb water; when present, ADH induces expression of water transport proteins in the late distal tubule and collecting duct to increase water reabsorption.

Detailed explanation-5: -ADH reduces water loss via lowered urine volume. Extracellular dehydration (hypovolaemia) stimulates specific vascular receptors that signal brain centres to initiate drinking and ADH release.