Question

The hormone which reduces the sodium loss through urine and sweat is
A. Calcitonin
B. Aldosterone
C. Parathormone
D. Vasopressin

Answer 1

Hint: It maintains the electrolyte balance in the body. By acting on organs like kidney and colon, it increases the amount of sodium reabsorbed into the bloodstream thereby regulating the blood pressure.

Complete Answer:
A. Calcitonin- Calcitonin, also called thyrocalcitonin, is secreted by the parafollicular cells (C cells) in the thyroid gland in humans, and in many other animals in the ultimo pharyngeal body. Calcitonin reduces calcium levels in the blood by the following mechanism:
Calcitonin inhibits the activity of osteoclasts. Osteoclasts break down the bone to release calcium into blood. The inhibition by calcitonin reduces this for a short period of time.
Calcitonin also decreases the resorption of calcium in the kidneys.

B. Aldosterone is the main mineralocorticoid hormone secreted by the zona glomerulosa of the adrenal cortex. It is necessary for sodium regulation in the kidney, salivary glands, sweat glands and colon. It stimulates sodium and water reabsorption from the gut, salivary and sweat glands in exchange of potassium.

C. Parathormone, also called parathyroid hormone, is secreted by the parathyroid glands. It regulates the calcium level by its effects on bone, kidney, and intestine. It stimulates the release of calcium from bones into the blood which results in bone destruction and decreases the formation of a new bone. In kidneys it decreases the loss of calcium in urine. In the intestine, PTH increases calcium absorption from food by its effect on vitamin D metabolism.

D. Vasopressin, also called antidiuretic hormone, is a peptide hormone formed in the hypothalamus, then transported via axons to the posterior pituitary, which releases it into the blood. It maintains the volume of water in the extracellular fluid that surrounds cells. Other functions include vasoconstriction, renal water homeostasis etc.

Thus, it is clear from the above explanation that the correct option is option B.

Note: Aldosterone, a steroid hormone, has a major role in regulating salt and water and thereby regulating the blood pressure of the body.