Parathyroid gland

You have tiny parts in your neck.

Most people have four of them. They are small and yellowish-brown. They look like little seeds.

These parts have a big job. They watch the calcium in your blood. Calcium helps your muscles work well.

If your calcium is too low, these parts work. They send out a special signal. This signal tells your bones to release calcium.

This helps keep your blood levels just right. Your body needs this to stay healthy. It is amazing how they work!

You have small parts in your neck called parathyroid glands.

Most people have four of them. They sit behind the thyroid gland. They are yellowish-brown and flat. They look like small lentil seeds. Each gland is about 6 mm long.

These glands have a very important job. They help keep calcium levels steady in your blood. They also help with phosphate levels. This is vital for your muscles and nerves.

They do this by making parathyroid hormone. This is a special signal the body sends out. If blood calcium is too low, the glands act. They tell the bones to release calcium. They also tell the kidneys to save calcium.

Sometimes, these glands do not work quite right. If they make too much hormone, it is called hyperparathyroidism. This can cause bone pain. If they do not make enough, it is called hypoparathyroidism. This can happen if the glands are damaged during surgery.

Scientists first found these glands in 1852. They found them in the Indian rhinoceros first. Later, they found them in humans too.

You have tiny parts in your neck called parathyroid glands.

Most humans have four of these small glands. They sit right behind the thyroid gland. They are yellowish-brown and shaped like flat seeds. Each gland is about 6 mm long. They are also about 3 to 4 mm wide. You cannot see or feel them when someone checks your neck. These glands are very important for your health. They help keep your body working well every day.

These glands work by managing your calcium and phosphate levels. They do this by making a protein called parathyroid hormone (PTH). This hormone acts like a messenger for your body. If your blood calcium gets too low, the glands release PTH. This hormone tells your bones to release some calcium. It also tells your kidneys to save calcium instead of letting it leave your body. Finally, it helps your gut absorb more calcium from food. This keeps your nervous and muscular systems working properly.

Scientists learned about these glands a long time ago. In 1852, Richard Owen first found them in an Indian rhinoceros. He described them as small, yellow bodies attached to the thyroid. A Swedish student named Ivar Sandström found them in humans in 1880. He noticed they were also in dogs, cats, and horses. In 1891, other scientists saw that removing the glands caused muscle problems. Later, in 1928, Isaac Y. Olch performed a successful removal of a gland. This helped patients who were struggling with muscle weakness.

There are many interesting facts about how these glands grow. In a growing embryo, they start in things called pharyngeal pouches. The glands actually change their final positions as the body grows. The lower glands come from the third pouch and move down with the thymus. The higher glands come from the fourth pouch. Most people have four glands, but some have six or even eight. Sometimes, these glands can even be found in the chest or the thymus. This happens if they do not detach properly during growth.

Understanding these glands helps us understand how our whole body stays in balance. If the glands make too much hormone, it is called hyperparathyroidism. This can lead to bone pain or dehydration. If they do not make enough, it is called hypoparathyroidism. This can happen if the glands are hurt during thyroid surgery. This is similar to how a thermostat controls the heat in a house. If the thermostat breaks, the house might get too hot or too cold. Your parathyroid glands act like a thermostat for your blood calcium.

The parathyroid glands are small endocrine glands located in the neck of humans and other tetrapods.

These glands are essential for maintaining homeostasis, which is the body's internal balance. Specifically, they regulate the levels of calcium and phosphate in the blood. This regulation is vital because the nervous and muscular systems require precise calcium levels to function correctly. Without this control, the body cannot maintain the stability needed for life.

These glands operate through a complex hormonal mechanism. When blood calcium levels drop, the parathyroid glands secrete parathyroid hormone, also known as parathormone. This small protein acts on several different parts of the body to raise calcium. First, it stimulates osteoblasts to indirectly trigger osteoclasts, which are cells that break down bone to release calcium into the blood. Second, it activates vitamin D to increase calcium absorption in the gastrointestinal tract. Finally, the hormone tells the kidneys to conserve calcium through reabsorption rather than letting it leave through urine.

Structurally, the parathyroid glands are quite distinct from the nearby thyroid gland. While the thyroid has a follicular structure, the parathyroid glands consist of densely packed cells. There are two primary types of cells found within these glands. Chief cells are responsible for synthesizing and releasing parathyroid hormone. These cells appear dark when they are loaded with the hormone and clear when they are in a resting state. Oxyphil cells are also present; they appear lighter and their specific function remains unknown, though they increase in number as a person ages.

Anatomy and development of these glands involve interesting movements during embryological growth. The glands originate from the endoderm of the third and fourth pharyngeal pouches. Interestingly, their final positions are the reverse of their starting points. The inferior parathyroid glands develop from the third pouch and move downward as the thymus migrates toward the chest. The superior glands develop from the fourth pouch and do not migrate as far. Because of this movement, the glands are named based on their final location rather than their origin.

Most humans possess four parathyroid glands, though there is significant natural variation. Some individuals may have three, six, eight, or even more glands. These glands are typically yellowish-brown, flat, and ovoid, resembling a lentil seed. A single gland is usually about 6 mm long and 3 to 4 mm wide. In healthy adults, the glands weigh approximately 30 mg in men and 35 mg in women. They are located on the posterior surface of the thyroid and cannot be felt during a physical exam.

Medical science has a long history of studying these small structures. Richard Owen first described them in 1852 after observing an Indian rhinoceros. In 1880, Ivar Sandström discovered them in humans and other animals like dogs and horses. By 1908, William G. MacCallum proposed their specific role in calcium metabolism. The isolation of parathyroid hormone occurred in the 1920s by Adolph M. Hanson and James B. Collip. Later, research by Roger Guillemin, Andrew Schally, and Rosalyn Sussman Yalow earned a Nobel Prize in 1977.

When the glands do not function correctly, it leads to specific medical conditions. Hyperparathyroidism occurs when there is an excess of parathyroid hormone, which can cause bone pain or dehydration. This can be primary, caused by cell growth, or secondary, caused by renal disease. Conversely, hypoparathyroidism is a state of deficient hormone activity. This can result from damage during thyroid surgery or genetic conditions like DiGeorge syndrome. There is even a rare condition called pseudohypoparathyroidism, where the body is resistant to the hormone itself.