What is the role of parathyroid hormone in the body?

Parathyroid hormone (PTH) plays a vital role in maintaining calcium homeostasis within the body. It is secreted by the parathyroid glands and functions primarily to increase blood calcium levels when they drop too low. PTH achieves this by promoting several physiological processes:

Firstly, it stimulates the release of calcium from bones into the bloodstream, thereby increasing the calcium level in the blood. It also enhances the reabsorption of calcium in the kidneys, which means that less calcium is lost in urine. Additionally, PTH promotes the conversion of vitamin D into its active form, calcitriol, in the kidneys, which in turn increases the intestinal absorption of calcium from dietary sources.

Overall, the role of PTH is crucial for the regulation of calcium levels, which are essential for various bodily functions, including muscle contraction, blood clotting, and nerve function. Thus, its primary function revolves around maintaining calcium homeostasis in the body.