Calcitonin is secreted by

Question

Question

This question was previously asked in

RRB Pharmacist Exam Paper 2019

Answer 1

Correct Answer: Thyroid

Rationale:

Calcitonin is a hormone produced by the parafollicular cells (also known as C cells) of the thyroid gland. It plays a crucial role in calcium and phosphate metabolism.
Calcitonin helps to regulate calcium levels in the blood by inhibiting the activity of osteoclasts, the cells that break down bone, thereby promoting the deposition of calcium into bones.
The secretion of calcitonin is primarily stimulated by increased blood calcium levels. When calcium levels are high, calcitonin helps to lower them to maintain homeostasis.

Explanation of Other Options:

Parathyroid

Rationale: The parathyroid glands, typically four small glands located on the back of the thyroid gland, secrete parathyroid hormone (PTH). PTH increases blood calcium levels by stimulating osteoclast activity, increasing calcium absorption in the intestines, and reducing calcium loss in the urine.

Adrenals

Rationale: The adrenal glands, located on top of each kidney, produce a variety of hormones including cortisol, aldosterone, and adrenaline. These hormones regulate metabolism, immune response, blood pressure, and stress responses, but are not involved in calcium regulation.

Thymus

Rationale: The thymus gland, located behind the sternum and between the lungs, is primarily involved in the development of the immune system, particularly in the maturation of T-lymphocytes (T-cells). It does not secrete calcitonin or any hormones related to calcium regulation.

Conclusion:

Among the given options, the thyroid is the gland responsible for secreting calcitonin. This hormone plays a vital role in calcium homeostasis in the body, distinguishing it from the functions of the parathyroid, adrenal, and thymus glands.