Parathyroid Gland

The parathyroid glands are small endocrine glands located in the neck, behind the thyroid gland. Most people have four parathyroid glands, but 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 calcium levels in the body.

Functions of the Parathyroid Gland

The main function of the parathyroid gland is to regulate the levels of calcium and phosphate in the body. Parathyroid hormone (PTH) helps maintain calcium homeostasis by acting on the bones, kidneys, and intestines.

Effects of Parathyroid Hormone (PTH)

• Bone: PTH stimulates the release of calcium from the bones into the bloodstream, increasing blood calcium levels.
• Kidneys: PTH enhances the reabsorption of calcium and the excretion of phosphate in the kidneys, helping to conserve calcium in the body.
• Intestines: PTH indirectly promotes the absorption of calcium from the intestines by stimulating the production of activated vitamin D, which is essential for calcium absorption.

Disorders of the Parathyroid Gland

Imbalances in parathyroid hormone levels can lead to various disorders, including:

1. Hyperparathyroidism: This condition occurs when the parathyroid glands produce too much PTH, leading to elevated blood calcium levels (hypercalcemia). Symptoms may include fatigue, kidney stones, and weakened bones.
2. Hypoparathyroidism: In contrast, hypoparathyroidism results from insufficient PTH production, leading to low blood calcium levels (hypocalcemia). This can cause muscle cramps, seizures, and other neurological symptoms.

Study Guide

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

1. Location and number of parathyroid glands
2. Function of parathyroid hormone (PTH) in calcium regulation
3. Effects of PTH on bones, kidneys, and intestines
4. Disorders associated with parathyroid gland imbalances

Understanding the role of the parathyroid gland and its hormone, PTH, is important for comprehending calcium homeostasis and related medical conditions.