The parathyroid glands primarily regulate calcium and phosphate levels in the body. They achieve this by secreting parathyroid hormone (PTH), which responds to low blood calcium levels. PTH maintains homeostasis to support nervous and muscular function.
Hormone Mechanism
PTH raises blood calcium by stimulating bone breakdown, enhancing kidney reabsorption of calcium, and promoting intestinal absorption via vitamin D activation. It lowers phosphate by inhibiting kidney reabsorption.
Location and Structure
Typically four small glands sit behind the thyroid in the neck. Chief cells produce PTH, regulated inversely by serum calcium through feedback loops.