The parathyroid is a special gland in the body. There are actually four parathyroid glands. Two pairs of these tiny pea-shaped structures rest on the back of the THYROID gland. The parathyroid glands secrete a hormone called parathormone.
Parathormone controls the amount of calcium and phosphorus in the blood and the way in which these minerals are used by the body. Normally there is a balance in the body between the level of calcium and phosphorus. When there is too little parathyroid hormone, there is a rise in the level of phosphorus in the blood and a drop in the level of calcium. If blood calcium is markedly decreased, a condition called tetany occurs. In such cases, the muscles of the body become irritable and contract, producing spasms throughout the body. The muscles of the larynx may be involved and obstruct the passage of air from outside into the lungs. The muscles controlling breathing go into spasm. Death results in severe cases. Accidental removal of the parathyroid glands during surgery can produce the same effect.
Oversecretion of the parathyroids is called hyperparathyroidism. It may be caused by tumors of the glands or by other disturbances of calcium-phosphorus metabolism. The blood level of calcium rises and the level of phosphorus falls. In such a condition there is a loss of calcium from the bones. This calcium loss causes a weakening of the bone structure. Bone pain, fractures, bone deformities, kidney stones, and nephritis often result.
