Understanding the Parathyroid Glands

Understanding the Parathyroid Glands

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Understanding the Parathyroid Glands

The parathyroid glands are 4 pea-sized glands located behind the thyroid gland. Their main job is to keep the level of calcium in the blood within a certain range. This helps the muscles and nerves work properly and also keeps bones strong. When there is a problem with the parathyroid glands, the blood calcium level may get too high. This has effects throughout the body.

Front view of neck showing voicebox (larynx), thyroid gland, parathyroid glands, windpipe (trachea), the laryngeal nerve, and the large blood vessels.

Back view of thyroid gland showing four small parathyroid glands near bottom of thyroid.

The parathyroid glands

The parathyroid glands are found behind the thyroid gland in the neck. The parathyroid glands control the level of calcium and phosphorus in the blood by making parathyroid hormone (PTH). This is a chemical messenger that tells the body how to control calcium.

How the parathyroid glands work

When the blood calcium level is low, the glands make more PTH. This tells the body to increase the amount of calcium in the blood. To increase the blood calcium level, the body may absorb more calcium from food in the intestines. It may also take calcium from the bones. When the blood calcium level is high, the glands make less PTH. This tells the body to decrease the amount of calcium in the blood. To decrease the blood calcium level, less calcium is absorbed by the gut, less calcium is taken from the bones, and more calcium is filtered out of the blood by the kidneys.