What function does calcitonin serve in the body?

Calcitonin plays a vital role in the regulation of calcium homeostasis within the body. Its primary function is to decrease blood calcium levels. It is produced by the parafollicular cells (C-cells) of the thyroid gland and helps to inhibit osteoclast activity in the bones, which are the cells responsible for bone resorption. By suppressing osteoclast function, calcitonin reduces the release of calcium from bones into the bloodstream, thereby contributing to lower serum calcium levels.

Additionally, calcitonin promotes the renal excretion of calcium by increasing its urinary excretion, further assisting in the reduction of blood calcium levels. This function is particularly important during periods when blood calcium levels are elevated, preventing potential complications associated with hypercalcemia.

Understanding the role of calcitonin helps in recognizing how hormonal regulation contributes to maintaining calcium balance, which is crucial for various physiological processes including muscle contraction, nerve function, and blood clotting.