What hormone raises blood calcium levels and is secreted by the parathyroid glands?

The hormone that raises blood calcium levels and is secreted by the parathyroid glands is parathyroid hormone (PTH). This hormone plays a crucial role in calcium homeostasis in the body. When blood calcium levels drop, the parathyroid glands release PTH, which has several important effects: it stimulates the release of calcium from bones, increases calcium reabsorption in the kidneys, and enhances the activation of vitamin D in the kidneys, which in turn increases intestinal absorption of calcium.

The role of PTH is vital for maintaining adequate calcium levels for various physiological functions, including muscle contraction, nerve function, and blood coagulation. Without sufficient levels of this hormone, the body could not effectively control calcium levels, which could lead to various health issues such as osteoporosis or hypocalcemia.

The other hormone options listed, while involved in glucose and calcium metabolism, do not raise blood calcium levels in the same way PTH does. For instance, insulin and glucagon primarily regulate glucose levels in the blood and do not influence calcium levels directly. Calcitonin, although involved in calcium regulation, serves to lower blood calcium levels, which is the opposite function of PTH. Hence, parathyroid hormone is the correct choice for regulating and raising blood