Question

The primary target organ of aldosterone is:
(A) The kidney
(B) The pancreas
(C) The liver
(D) All of the above

Answer 1

Hint: Aldosterone is a part of the renin-angiotensin mechanism.

Step by step explanation:
Aldosterone is a mineralocorticoid hormone. It is a steroidal hormone synthesized in the zona glomerulosa of the adrenal cortex. The main area of action of the hormone is the tubule system in the kidney i.e. the distal tubules and collecting tubules of the nephron. The main function is to maintain blood pressure and the amount of sodium and potassium in the body. It helps in the reabsorption of sodium from the kidney and allows the excretion of potassium from the tube such that it prevents water loss and also helps in controlling the blood volume.
The main function of the hormone is thus:
(i) It activates the Na/K pump by releasing 3 Na ions in the intestinal fluid and 2 K ions in the cells creating a gradient that allows the reabsorption of Na and water into the blood and potassium into the urine.
(ii) It helps to activate the H+/ATPase transport in the collecting tubes.
The function in renin angiotensin mechanism:
Angiotensin is responsible for the regulation and the functioning of aldosterone in the body. A fall in the globular blood pressure causes the JG cells to release the hormone renin which will convert angiotensin to angiotensin I and further to angiotensin II. The angiotensin II will stimulate the adrenal cortex to release aldosterone which will help in absorption of sodium and potassium sodium ion and water from the distal part of the tubule. This leads to an increase in blood pressure.

Thus, the primary target organ is the kidney.

Note:
The adrenal gland secretes a lot of other essential hormones. They are mostly steroidal in nature. The pancreas is a gland which secretes pancreatic juices essential for digestion. They also are used in regulating diabetics. The liver produces bile and other digestive juices. It is the largest gland in our body.