Parathyroid Gland

The parathyroid glands are small endocrine glands located in the neck, behind the thyroid gland. Most people have four parathyroid glands, although the number can vary from person to person. These glands are responsible for producing and secreting parathyroid hormone (PTH), which plays a crucial role in regulating the levels of calcium and phosphorus in the body.

Functions of the Parathyroid Gland

Parathyroid hormone (PTH) has several important functions in the body:

1. Regulation of Calcium Levels: PTH helps to regulate the levels of calcium in the blood by acting on the bones, kidneys, and intestines. It stimulates the release of calcium from the bones, enhances the reabsorption of calcium by the kidneys, and promotes the activation of vitamin D, which helps in the absorption of calcium from the intestines.
2. Regulation of Phosphorus Levels: PTH also plays a role in regulating the levels of phosphorus in the blood. It acts on the kidneys to increase the excretion of phosphorus, thereby helping to maintain the balance of calcium and phosphorus in the body.
3. Stimulation of Vitamin D Production: PTH stimulates the production of active vitamin D (calcitriol) in the kidneys, which is essential for the absorption of calcium from the intestines.

Disorders of the Parathyroid Gland

Disorders of the parathyroid gland can lead to imbalances in calcium and phosphorus levels, resulting in various health problems. The two primary disorders associated with the parathyroid gland are:

1. Hyperparathyroidism: This condition occurs when the parathyroid glands produce too much PTH, leading to elevated levels of calcium in the blood (hypercalcemia). Hyperparathyroidism can be caused by a benign tumor on one of the parathyroid glands or by the overgrowth of multiple glands. Symptoms may include fatigue, weakness, kidney stones, and bone pain.
2. Hypoparathyroidism: In contrast, hypoparathyroidism occurs when the parathyroid glands produce too little PTH, resulting in low levels of calcium in the blood (hypocalcemia). This can lead to muscle cramps, spasms, and neurological symptoms due to the reduced levels of calcium.

Study Guide

Here are some key points to remember about the parathyroid gland:

• The parathyroid glands are small endocrine glands located behind the thyroid gland in the neck.
• They produce and secrete parathyroid hormone (PTH), which regulates calcium and phosphorus levels in the body.
• PTH acts on the bones, kidneys, and intestines to maintain calcium and phosphorus balance.
• Disorders of the parathyroid gland, such as hyperparathyroidism and hypoparathyroidism, can lead to imbalances in calcium and phosphorus levels, causing various health problems.
• Hyperparathyroidism is characterized by elevated blood calcium levels, while hypoparathyroidism is characterized by low blood calcium levels.