Question

Deficiency of a hormone increases $K^+$ ion and decreases $Na^+$ ions in blood is secreted by.
A. Zona Fasciculata
B. Zona glomerulosa
C. Zona reticulata
D. Zona Pellucida

Answer 1

Hint: Hormones which are responsible for the maintenance of ionic balance of the blood are called Mineralocorticoids. Such hormones are secreted by Adrenal gland cortex.

Complete Answer:
- Adrenal gland or the suprarenal gland has two parts. It has an outer cortex and inner medulla. Cortex is mesodermal in origin and is epithelial in tissue structure. Cortex is further divided into three layers. From outer to inner these layers are Zona Glomerulosa, Zona Fasciculata and Zona Reticulata.
- Zona Glomerulosa secretes Mineralocorticoids, Zona Fasciculata secrete Glucocorticoids and Zona reticulata secrete androgen. Adrenal Medulla is ectodermal in origin and is modified sympathetic ganglion. They secrete hormone Epinephrine (Adrenalin) and Nor-epinephrine ( Noradrenaline)
- Mineralocorticoids which are secreted by Zona Gomerulata are responsible for marinating the ionic balance of $Na^+$ and $K^+$ in the blood. Major mineralocorticoid is Aldosterone. Aldosterone acts on DCT and collects the duct of the nephron. It increases the $Na^+$ reabsorption and increases the $K^+$ secretion. It increases $K^+$ to be excreted through the urine and decreases $Na^+$ excretion in urine. Thus it causes an increase in $Na^+$ level in the blood and decrease in $K^+$ level in the blood.

Additional Information: Adrenal cortex secretion is under the control of ACTH hormone secreted by pituitary gland. But Aldosterone is not under the control of ACTH. It is activated by the RAAS mechanism of the kidney. The RAAS mechanism releases Angiotensin-II which stimulates the zona glomerulosa of the adrenal cortex to release aldosterone.

Thus the correct option is Option B- Zona Glomerulosa.

Note: Zona Pellucida is not concerned with the adrenal cortex. It is the non-cellular glycoprotein layer present on the secondary oocyte (Ovum/female gamete). While fertilization sperm has to break zona pellucida by secreting zona lysine from acrosome.