Question

The blood calcium level is lowered by the deficiency of

• A. Calcitonin
• B. Both calcitonin and parathormone
• C. Thyroxine
• D. Parathormone

Answer 1

The correct option is D

Parathormone

The correct option is D.

Explanation of the correct option:

1. The main cells of the parathyroid gland, which is positioned near the thyroid gland, secrete the hormone parathormone.
2. Its lack causes a decrease in blood calcium levels.
3. The hormone parathormone deficiency lowers the blood calcium level.
4. This hormone is also known as parathyroid hormone.
5. The parathyroid is an endocrine gland that produces some hormones.
6. Through its actions on bone, kidney, and gut, it modulates serum calcium ion concentration.

Explanation of the incorrect options:

Option A:

1. Calcitonin deficiency causes an increase in blood calcium levels.
2. This is a hormone that is produced by the C-cells of the thyroid gland.
3. It works when there is a high concentration of calcium present in the blood.

Option B:

1. Both calcitonin and parathormone regulate the blood calcium level.
2. Calcitonin is produced by the C-cells of the thyroid gland.
3. Parathormone is secreted by the chief cells of the parathyroid that will just regulate the metabolism of the calcium and phosphate

Option C:

1. Thyroxine is the major hormone released by the thyroid gland into the bloodstream.
2. It is necessary for digestion, heart and muscle function, brain growth, and bone maintenance.
3. Thyroxine is secreted by the thyroid gland.

Final answer: The blood calcium level is lowered by the deficiency of parathormone.