The Parathyroid Glands

Humans usually have four parathyroid glands. These are situated at the rear of the thyroid gland. The parathyroid glands control the calcium levels in our blood and in our bones.

The parathyroid glands produce parathyroid hormone (PTH), which controls calcium and phosphate balance as well as the physiology of our bones. PTH has a variety of effects including raising blood calcium levels (by breaking down and releasing calcium in our bones), increasing calcium absorption in the digestive system and it also affects our sense of well being.

PTH has an opposite effect to calcitonin from the thyroid gland. Calcitonin and PTH are involved in a balancing act, which regulates our calcium balance.