Question

If a person drinks large amounts of water in a short period of time, he may die of water toxicity. ADH can help prevent water retention by interaction with target cells in

• A. Posterior pituitary
• B. Kidney
• C. Bladder
• D. Adrenal gland

Answer 1

The correct option is B Kidney

ADH interacts with target cells in the kidney and helps in regulation of homeostasis. Antidiuretic hormone (ADH), also called vasopressin, is secreted by the posterior pituitary gland in response to an increase in the osmotic concentration of the blood plasma. Dehydration, for example, causes the blood volume to decrease while the remaining plasma becomes more concentrated. This stimulates osmoreceptors in the hypothalamus of the brain. The osmoreceptors promote thirst and stimulate ADH secretion from the posterior pituitary gland. ADH, in turn, stimulates the kidneys to retain more water in the blood, excreting less in the urine. A dehydrated person thus drinks more and urinates less, helping to raise the blood volume and restore homeostasis. When ADH is absent, the kidneys do not retain water and excessive quantities of urine are produced.