Parathyroid

Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods that produce parathyroid hormone. Humans usually have four parathyroid glands, which are usually located on the back of the thyroid gland, or, in rare cases, within the thyroid gland itself or in the chest. Parathyroid glands control the amount of calcium in the blood and within the bones.

Structure

The parathyroid glands are two pairs of glands usually positioned behind the left and right lobes of the thyroid. They are small, light-colored lumps of tissue, usually about the size of a grain of rice. They are located in the neck, near the thyroid gland, but are separate from it.

Function

The sole function of the parathyroid glands is to regulate the body's calcium and phosphate levels. It does this by secreting parathyroid hormone (PTH), a hormone that regulates the amount of calcium and phosphate in the blood and helps control calcium levels in the various organs of the body.

Clinical significance

Diseases of the parathyroid glands include hyperparathyroidism, hypoparathyroidism, and parathyroid cancer. Hyperparathyroidism, the overproduction of parathyroid hormone, can cause a range of symptoms including bone pain, kidney stones, excessive urination, abdominal pain, fatigue, depression, and confusion. Hypoparathyroidism, the underproduction of PTH, can lead to low blood calcium levels, resulting in muscle cramps and spasms. Parathyroid cancer is rare.

See also

• Endocrine system
• Parathyroid hormone
• Hyperparathyroidism
• Hypoparathyroidism
• Parathyroidectomy

References

Parathyroid Resources
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