Question

What is the function of the thyrocalcitonin hormone?
A. Sugar control in blood
B. Calcium control in blood
C. Cholesterol control in blood
D. Proteins control in blood

Answer 1

Hint: Thyroid is the largest endocrine gland, composed of follicles and stromal tissue. The stroma contains parafollicular cells or the C-cells, which secrete thyrocalcitonin(TCT).

Complete answer: The thyroid gland is the largest endocrine gland. It is located on either side of the upper part of the trachea below the larynx. It is dark brown and H-shaped/butterfly bilobed gland. Its two lobes are connected by a narrow isthmus, a thin flap formed of non-glandular connective tissue. The thyroid gland is made up of follicles and stromal tissue. Every thyroid follicle is made up of follicular cells, encasing a cavity. These follicular cells synthesize two iodinated hormones:
1. Tetraiodothyronine or thyroxine
2. Triiodothyronine
 Iodine is basic for the typical pace of hormone formation in the thyroid. The stroma contains a small cluster of parafollicular cells or C cells which secrete non-iodinated hormone calcitonin or thyrocalcitonin(TCT). The secretion of TCT is regulated by increased plasma levels of calcium by the feedback mechanism. TCT lowers the calcium levels in the blood by increased calcium deposition in the bones and also stimulates the excretion of calcium in the urine.
So, the correct answer is option B-Calcium control in blood.

Note: The parathyroid hormone plays a significant role in calcium balance in the body along with TCT. PTH increases calcium levels in the blood(hypercalcemic hormone) in the following ways:
-By promoting absorption of calcium from food in the intestine.
-Reabsorption of calcium from nephrons in the kidneys. Simultaneously, it accelerates the elimination of phosphates in the urine.
-By promoting the release of Calcium from the bone matrix into the blood.