Optometry Admission Test (OAT) Practice 2025 - Free Optometry Admission Test Practice Questions and Study Guide

Calcitonin plays a significant role in regulating calcium levels in the body. It is a hormone produced by the parafollicular cells (C cells) of the thyroid gland and is primarily involved in lowering blood calcium levels. When blood calcium levels rise, calcitonin is secreted to help facilitate the deposition of calcium into the bones and inhibit the resorption of calcium from the bones by osteoclasts, the cells responsible for breaking down bone tissue.

This action effectively decreases the concentration of calcium in the bloodstream, contrasting with parathyroid hormone (PTH), which raises blood calcium levels by stimulating osteoclast activity and enhancing renal reabsorption of calcium. Therefore, the crucial function of calcitonin is to counterbalance the effects of PTH and maintain calcium homeostasis, ultimately contributing to bone health and mineralization.

Understanding this role is essential, as it highlights the intricate hormonal regulations that maintain homeostasis in the body, particularly concerning minerals like calcium that are vital for many physiological processes.