Question

AntiDiuretic Hormone acts on
A. Collecting tubule of kidney
B. Loop of Henle
C. Collecting ducts of testes
D. None of the above

Answer 1

Hint: ADH actively monitors the quantity of water within the body and controls it. It acts on the kidneys and therefore the blood vessels and functions to regulate the vital sign. It's a hormone that helps in controlling various physical processes and several other life-threatening conditions, including bleeding abnormalities and septic shocks.

Complete Answer:
- Antidiuretic hormone (ADH) is additionally called Vasopressin. The antidiuretic hormone is secreted by the neurohypophysis of the pituitary. Since it stimulates the constriction of blood vessels and leads to a rise in vital signs. Therefore, it's called vasopressin.
- It is mainly involved in regulating and balancing the quantity of water within the blood and increasing the glomerular blood flow by increasing the vital sign. Higher the concentrations of ADH tightens the blood vessels, which increases the vital sign.
- The ADH is produced within the hypothalamus, which is stored and secreted by the pituitary which lies just beneath the bottom of the brain.
- So, the most factor that controls what proportion of water the kidney excretes is ADH. When mammals begin to dehydrate, blood volume drops, and this is often detected by the hypothalamus of the brain. It stimulates the pituitary to release the hormone ADH.
- Now ADH acts on the collecting duct of the kidney by binding to the receptors on the principal cell within the collecting duct. When it binds, it causes the cell to supply aquaporins (are the channels that allow water to undergo freely) into its apical membrane.
- So, the water molecules from the urine are reabsorbed by aquaporins thus producing a little volume of urine once we are dehydrated.

Thus, the correct option is A (collecting tubules of the kidneys).

Note: The drive of water reabsorption is due to the high concentration within the medullary region of the kidney. In high concentrations, ADH can also act on the blood vessels to increase peripheral vascular resistance because of which the blood pressure increases.