Question

The blood calcium level is lowered by the deficiency of.
A. Thyroxine
B. Calcitonin
C. Parathormone
D. Both (a) and (b)

Answer 1

Hint: It is secreted by four small glands in the neck, located behind the thyroid gland. It regulates calcium levels in the blood, largely by increasing the levels when they are too low.

Complete answer: Calcium helps build strong bones and teeth. It is important for heart function, and helps in muscle contraction, blood clotting and nerve signalling. The normal range for the total blood calcium in the body is between 8.6 and 10.2 milligrams per deciliter (mg/dL).

Now let us find the answer from the given options-
1. Thyroxine is the main hormone secreted into the bloodstream by the thyroid gland. The deficiency of thyroxine leads to a condition called hypothyroidism. It lowers the metabolic rate, causing weight gain, memory problems, infertility, fatigue, and muscle stiffness.
2. Calcitonin is a hormone that is produced in humans by the parafollicular cells of the thyroid gland. It helps to regulate levels of calcium and phosphate in the blood and lowers the calcium levels in the blood opposing the action of parathyroid hormone.
3. Parathyroid hormone controls the levels of calcium in the blood, often by raising the levels when they are very low. It does this by acting on the liver, bones and intestines.
4. Hypoparathyroidism is the condition of reduced parathyroid hormone (PTH) secretion. This lack of PTH contributes to reduced calcium levels in the blood and elevated phosphorus levels in the blood.

Thus, the correct answer is option C i.e., parathormone.

Note: Hypercalcemia is a condition caused by above average calcium level in the blood. Too much calcium in the blood will weaken our bones, cause muscle weakness, kidney stones and interfere with the functions of heart and brain.