Question

Aldosterone is secreted by
a. Zona glomerulosa
b. Zona fasciculata
c. Zona reticularis
d. Zona pellucida

Answer 1

Aldosterone is a hormone produced from the adrenal glands. It is a steroid hormone which helps in regulation of salt and water in our body and affects our blood pressure. It stimulates the reabsorption of water and sodium, causing excretion of phosphate ions along with potassium.

Complete answer:
Aldosterone is produced in the outer layer of the cortex of the adrenal glands. Adrenal glands are a pair of endocrine glands that are present on the top surface of both the kidneys. They have two major regions- outer cortex and inner medulla. Cortex is further divided into several zones. Aldosterone is produced in the Zona glomerulosa, zone of the cortex, which is the outermost layer of the cortex of adrenal glands. The word ‘glomus’ means ball, thus defining the shape of the cells that are clusters of oval shaped secretory cells. Zona glomerulosa secretes mineralocorticoid hormones which have a main function of fluid balance.

Hence, the correct answer is option (A).

Additional information:
Zona glomerulosa lies just below the adrenal capsule and contributes to about 15% thickness of the cortex. The clusters of zona glomerulosa are separated by bands of connective tissue known as trabeculae. Trabeculae help in supply of blood to the secretory cells of zona glomerulosa.
Aldosterone controls the uptake of sodium ions as well as secretion of potassium ions in the collecting duct, thus it increases the reabsorption of sodium ions and excretion of potassium ions.

Note: Zona glomerulosa synthesises hormones (mineralocorticoids) that are very important for the maintenance of electrolytes and water in our body. The hormones synthesised are generally the steroid hormones that are synthesised from the cholesterol. Aldosterone is the most valuable hormone of all the secreted ones.