The parathyroid glands are small glands located behind the thyroid gland in the neck. These glands are responsible for regulating the body's calcium levels. Synonyms for the parathyroid glands include the parathyroids, parathyroid glands, and simply the para-thyroids. Additionally, the glands may be referred to as the chief cells, because they contain cells called chief cells that produce parathyroid hormone (PTH) which regulates calcium and phosphorus levels in the body. Other synonyms include the parathyroid adenomas, which are non-cancerous growths within the gland that can cause overproduction of PTH, and parathyroidectomy, which is the surgical removal of all or part of the gland.