Aldosterone is secreted by-

Ans. is 'a' i.e., Zona glomerulosa * The adrenal gland consists of an outer cortex and inner medulla. The hormones secreted by the adrenal cortex are called corticosteroid, which are classified into glucocorticoids, mineralocorticoids and androgens. The hormones secreted by the adrenal medulla are epinephrine and some norepinephrine. The adrenal cortex is essential for life; the adrenal medulla is not.* Adrenal cortex has three layers zona glomerulosa, zonafasciculata, and zona reticularis. The zona glomerulosa is the outermost layer and is the site of mineralocorticoid synthesis. The middle layer (zona fasciculata) and the innermost layer (zona reticularis) synthesize and secrete glucocorticoids and androgens. Though both layers (zona fasciculata & reticularis) secrete both hormones, zona fasciculata mainly secretes glucocorticoids and zona reticularis mainly secretes androgens.* Corticosteroids are classified as : i) Glucocorticoids; ii) Mineralocorticoids; and iii) Androgens.* Cortisol and cortisosterone are the chief natural glucocorticoids. They are so called because of their widespread effect on glucose (and protein) metabolism.* Aldosterone is the chief mineralocorticoid. It regulates K+ ions, sodium balance and ECF volume in the body.* Dehydroepindrosterone is the androgenic hormone secreted by the adrenal cortex.* All corticosteroid hormones act on intracellular cytoplasmic receptors.