The parathyroid glands are two small, oval-shaped glands located adjacent to the two thyroid gland lobes in the neck.
Parathyroid glands produce parathyroid hormone, which plays a role in the regulation of calcium levels in the blood. Precise calcium levels are important in the human body, since small deviations can cause muscle and nerve impairment.
The parathyroid hormone stimulates the following functions:
release of calcium by bones into the bloodstream
absorption of food by the intestines
conservation of calcium by the kidneys
Hypoparathyroidism is caused by underactive parathyroid glands. Underactive parathyroid glands produce too little parathyroid hormones, which in turn causes low levels of calcium in the blood stream.The low levels of calcium lead to tetany, an increased excitability of the nerves.Causes of hypoparathyroidism include accidental removal of a parathyroid gland when the thyroid is removed, or when part of the parathyroid tissue is removed.
Parathyroid tumors may cause increased levels of parathyroid hormones secreted by the parathyroid glands, leading to hyperparathyroidism. Most parathyroid tumors are benign (noncancerous) adenomas. Cancers of the parathyroid are very rare. If the tumor causes hyperparathyroidism, the tumor is surgically removed.