Parathyroid glands

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 rear surface 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

Parathyroid glands are small and round, and usually appear as yellowish-brown nodules on the surface of the thyroid gland. They are located on the posterior surface of the thyroid gland, and are usually four in number. However, the exact number can vary, with anything from two to six glands being reported in humans.

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 levels of calcium, phosphorus, and vitamin D in the blood and bone.

Clinical significance

Diseases of the parathyroid gland can lead to 'hyperparathyroidism' (the overproduction of parathyroid hormone) and 'hypoparathyroidism' (insufficient production of parathyroid hormone), both of which cause imbalances in the calcium and phosphate levels in the body. These imbalances can lead to a variety of symptoms, including weakness, depression, and kidney stones.

See also

• Endocrine system
• Hyperparathyroidism
• Hypoparathyroidism
• Parathyroid hormone

External links

• Parathyroid Gland Overview at parathyroid.com

Parathyroid glands Resources
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