The parathyroid glands are 4 small glands (each about the size of a grain of rice) found in the neck, close to the thyroid gland. They produce the hormone called parathyroid hormone (also called PTH).
This hormone is important because it helps control the amount of calcium and phosphorus in your body. Calcium and phosphorus combine to form calcium phosphate which is the main mineral needed to make your bones and teeth hard and strong. Parathyroid hormone controls how much calcium is taken from bones and absorbed in the gut.
When too much parathyroid hormone is secreted, levels of calcium in the blood rise, and bones may lose calcium phosphate, leading to osteoporosis (loss of bone density). The phosphorus released is lost in your urine (pee/mimi). Calcium going through your kidneys and out into your urine can also cause kidney stones.
This picture shows where the parathyroid glands (yellow) are located in your body in relation to the thyroid gland (pink) at the base of your neck.
Image credit: Colorado Community College System, Anatomy & Physiology
Note: The parathyroid glands are nothing to do with the thyroid gland. Parathyroid means near the thyroid. Parathyroid disorders shouldn't be confused with an underactive thyroid or overactive thyroid.
Video: Parathyroid Glands and Hyperparathyroidism: Amazing Animation.
The video below gives a summary of hyperparathyroidism and its treatment. It may take a few moments to load.
(Norman Parathyroid Center, US, 2012)