What is the role of calcitonin in the body?

Calcitonin is a hormone produced by the parafollicular cells (C cells) of the thyroid gland. Its primary role is to lower blood calcium levels when they become elevated. It achieves this mainly by inhibiting osteoclast activity in the bones. Osteoclasts are the cells responsible for bone resorption, a process that releases calcium into the bloodstream. By inhibiting these cells, calcitonin effectively reduces the release of calcium from bones, thereby lowering the overall calcium concentration in the blood.

Additionally, calcitonin has a role in promoting the activity of osteoblasts, the cells responsible for bone formation. This further contributes to its function in maintaining calcium homeostasis in the body, particularly in conditions of hypercalcemia.

The other options relate to different physiological processes that do not accurately describe the specific action of calcitonin. For example, calcitonin does not stimulate calcium absorption in the intestine, increase blood calcium levels, or stimulate adrenal function. Each of these functions is associated with different hormones, such as parathyroid hormone or vitamin D, which increase blood calcium levels, or hormones related to stress, which affect adrenal function.