Anatomy of the parathyroid glands

The parathyroid glands are four small, oval-shaped glands. They are located next to the two thyroid gland lobes in the neck. Each gland is often about the size of a pea.

Function of the parathyroid glands

Parathyroid glands produce parathyroid hormone (PTH). This hormone plays a key role in regulating calcium levels in the blood. Precise calcium levels are important because small changes can cause muscle and nerve problems.

PTH stimulates these functions:

• Release of calcium by bones into the bloodstream, which affects bone density and strength

• Calcium absorption from food by the intestines

• Calcium conservation by the kidneys

• Kidney cell stimulation, which changes the weaker forms of vitamin D into the form that is strongest at absorbing calcium from the intestines