What are Parathyroid Glands?

Parathyroid glands are four small glands of the endocrine system which regulate the calcium in our bodies. Parathyroid glands are located in the neck behind the thyroid where they continuously monitor and regulate blood calcium levels.

What do Parathyroid Glands do?

Parathyroid glands control the calcium levels in our blood, in our bones, and throughout our body. Parathyroid glands regulate the calcium by producing a hormone called Parathyroid Hormone (PTH). Calcium is the most important element in our bodies (we use it to control many organ systems), so calcium is regulated more carefully than any other element. In fact, calcium is the only element with it's own regulatory system -- the parathyroid glands.

Where are Parathyroid Glands located?

Parathyroid glands (we all have 4 of them) are normally the size of a grain of rice. Occasionally they can be as large as a pea and still be normal. The four parathyroids are located behind the thyroid and are shown in this picture as the mustard yellow glands behind the pink thyroid gland. Normal parathyroid glands are the color of spicy yellow mustard. The light blue tube running up the center of the picture is the trachea (wind pipe).

The voice box is the pink structure at the top of the picture sitting on top of the trachea. The carotid arteries are shown on both sides of the thyroid running from the heart up to the brain. NOTE: we are looking at the back side of the thyroid so we can see the parathyroid glands.

Remember, the parathyroids are behind the thyroid. Also note that this drawing shows three small (normal) parathyroid glands and one big diseased one--this is the typical situation of a patient with parathyroid disease--one of the parathyroid glands grows into a tumor and makes too much hormone.

If you have parathyroid disease, you very likely have 3 normal parathyroid glands the size of a grain of rice and one parathyroid tumor that is as big as an olive, grape, or even a walnut. If you have parathyroid disease (hyperparathyroidism) you will need an operation to remove the one parathyroid gland which has become a tumor. More about parathyroid disease on other pages...this page is about NORMAL parathyroid function.

One more introductory note... We must make sure you understand that the thyroid and parathyroid are NOT related. Although they are neighbors and both are part of the endocrine system, the thyroid and parathyroid glands are otherwise unrelated--they do not have the same function--just similar and confusing names!

The Role of Calcium in the Human Body... and how the Parathyroid Glands Control All Calcium Levels in our Bodies. First a word about CALCIUM and what it does in our bodies. We use many elements in our bodies to perform all the different functions of life. Calcium is essential to life, and is used primarily for three things:

To provide the electrical energy for our nervous system. The most important thing that calcium does in the human body is provide the means for electrical impulses to travel along nerves. Calcium is what the nervous system of our body uses to conduct electricity. This is why the most common symptoms of parathyroid disease and high calcium levels are related to the nervous system (depression, weakness, tiredness, etc, etc). Much more about symptoms of parathyroid disease on another page.

To provide the electrical energy for our muscular system. Just like the nerves in our bodies, our muscles use changes in calcium levels inside the cells to provide the energy to contract. When the calcium levels are not correct, people can feel weak and have muscle cramps.

To provide strength to our skeletal system. Everyone knows that calcium is used to make our bones strong, but this is really only half the story. The bones themselves serve as the storage system that we use to make sure we will always have a good supply of calcium.

Just like a bank vault where we constantly make deposits and withdrawals, we are constantly putting calcium into our bones, and constantly taking calcium out of our bones... all in small amounts... with the sole purpose of keeping our calcium levels in the blood at the correct level. Remember, the most important role of calcium is to provide for the proper functioning of our nervous system--not to provide strength to our bones--that is secondary.

Thus, calcium is the most closely regulated element in our bodies. In fact, calcium is the ONLY element / mineral that has its own regulatory system (the parathyroid glands). There are no other glands in our bodies that regulate any other element. Why? Because its our nervous system that separates us from all other plant and animal life--and calcium provides the electrical system for our nervous system.

When our calcium levels get elevated (almost always due to a bad parathyroid gland), then we can have changes in our personality (typically noticed by our loved ones) and many other nervous-system symptoms (depression, etc). So, parathyroid disease is not just about osteoporosis and kidney stones, it is primarily about us feeling "normal" and enjoying life.

The Role of the Parathyroid Glands -- to Regulate Calcium. The ONLY purpose of the parathyroid glands is to regulate the calcium level in our bodies within a very narrow range so that the nervous and muscular systems can function properly. This is all they do.

They measure the amount of calcium in the blood every minute of every day... and if the calcium levels go down a little bit, the parathyroid glands recognize it and make parathyroid hormone (PTH) which goes to the bones and takes some calcium out (makes a withdrawal from the calcium vault) and puts it into the blood. When the calcium in the blood is high enough, then the parathyroids shut down and stop making PTH.

The single major disease of parathyroid glands is over-activity of one or more of the parathyroids which make too much parathyroid hormone causing a potentially serious calcium imbalance (too high calcium in the blood). This is called hyperparathyroidism and this is the disease that this entire web site is about.

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