PTH

PTH or Parathyroid hormone is a hormone secreted by the parathyroid glands in the neck. It plays a crucial role in maintaining the body's calcium and phosphorus levels.

Function

PTH is responsible for increasing the concentration of calcium in the blood. It does this by stimulating the osteoclasts, the cells responsible for breaking down bone. When these cells break down bone, they release calcium into the bloodstream. PTH also promotes the absorption of calcium in the intestines and the reabsorption of calcium in the kidneys, further increasing blood calcium levels.

Regulation

The secretion of PTH is regulated by the level of calcium in the blood. When blood calcium levels are low, the parathyroid glands secrete more PTH. Conversely, when blood calcium levels are high, the parathyroid glands secrete less PTH.

Clinical significance

Abnormal levels of PTH can lead to several medical conditions. Hyperparathyroidism is a condition where the parathyroid glands secrete too much PTH, leading to high blood calcium levels. This can result in kidney stones, osteoporosis, and neurological disorders. Hypoparathyroidism, on the other hand, is a condition where the parathyroid glands do not secrete enough PTH, leading to low blood calcium levels. This can result in muscle cramps, seizures, and abnormal heart rhythms.

See also

• Calcitonin
• Vitamin D
• Parathyroidectomy