AP BIOLOGY

Detailed explanation-1: -In the case of dehydration, vasopressin or antidiuretic hormone (ADH) is secreted from the neurohypophysis or posterior pituitary. It causes reabsorption of water from distal convoluted tubules of the kidney and decreases the water excreted out in the urine.

Detailed explanation-2: -Antidiuretic hormone is made by a part of the brain called the hypothalamus and is secreted into the blood by the pituitary gland. Certain types of tumors may release high amounts of antidiuretic hormone, which can cause low levels of sodium in the blood and the body to retain water.

Detailed explanation-3: -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-4: -ADH travels in the bloodstream to its target organ, the kidneys. It causes the kidney tubules to become more permeable . This means more water can leave the kidney tubule to be reabsorbed back into the blood during selective reabsorption.

Detailed explanation-5: -Hyperosmolar states most strongly trigger its release. ADH is stored in neurons within the hypothalamus. These neurons express osmoreceptors that are exquisitely responsive to blood osmolarity and respond to changes as little as two mOsm/L. [2] Therefore, slight elevations in osmolarity result in the secretion of ADH.