Which hormone is produced by the thyroid gland and is responsible for lowering blood calcium levels?

The hormone that is produced by the thyroid gland and is responsible for lowering blood calcium levels is calcitonin. Calcitonin functions by inhibiting the activity of osteoclasts, the cells that break down bone and release calcium into the bloodstream. Additionally, it helps the kidneys accelerate the excretion of calcium in urine. This coordinated action effectively decreases the concentration of calcium in the blood.

This process is critical in maintaining calcium homeostasis in the body, especially after meals when calcium levels might temporarily rise. The thyroid gland's secretion of calcitonin complements the role of another hormone, parathyroid hormone (PTH), which increases blood calcium levels when they are too low. By providing this balance, calcitonin plays an essential part in ensuring that calcium levels remain within a healthy range, allowing for proper physiological function including bone health and muscle contraction.