AP BIOLOGY

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. A low level results in greater urine production.

Detailed explanation-2: -Low levels of anti-diuretic hormone will cause the kidneys to excrete too much water. Urine volume will increase leading to dehydration and a fall in blood pressure.

Detailed explanation-3: -Deficiency of ADH is usually due to hypothalamic-neurohypophyseal lesions (central diabetes insipidus) or insensitivity of the kidney to ADH (nephrogenic diabetes insipidus). These patients, if untreated, have the predictable result of dehydration, hyperosmolality, hypovolemia, and eventual death in severe cases.

Detailed explanation-4: -Urine volume and concentration is regulated through the same processes that regulate blood volume. Antidiuretic hormone (ADH)-produced by the posterior pituitary gland-increases the amount of water reabsorbed in the distal convoluted tubule and collecting duct.

Detailed explanation-5: -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.