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Thyroid Cancer

  • Posted: 10/26/2007

The Thyroid

Your thyroid is a gland at the front of your neck beneath your voice box (larynx). A healthy thyroid is a little larger than a quarter. It usually cannot be felt through the skin.

The thyroid has two parts (lobes). A thin piece of tissue (the isthmus) separates the lobes.

The thyroid makes hormones:

Four or more tiny parathyroid glands are behind the thyroid. They are on its surface. They make parathyroid hormone, which plays a big role in helping the body maintain a healthy level of calcium.

The pictures show the front and back of the thyroid.
The pictures show the front and back of the thyroid.


Glossary Terms

C cell (… sel)
A type of cell in the thyroid. C cells make calcitonin, a hormone that helps control the calcium level in the blood.
calcium (KAL-see-um)
A mineral needed for healthy teeth, bones, and other body tissues. It is the most common mineral in the body. A deposit of calcium in body tissues, such as breast tissue, may be a sign of disease.
gland (gland)
An organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva, or milk. Endocrine glands release the substances directly into the bloodstream. Exocrine glands release the substances into a duct or opening to the inside or outside of the body.
hormone (HOR-mone)
One of many chemicals made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.
isthmus (iz-muhs)
A narrow part inside the body that connects two larger structures.
larynx (LAYR-inx)
The area of the throat containing the vocal cords and used for breathing, swallowing, and talking. Also called voice box.
parathyroid gland (PAYR-uh-THY-royd...)
One of four pea-sized glands found on the surface of the thyroid. The parathyroid hormone made by these glands increases the calcium level in the blood.
thyroid hormone (THY-royd HOR-mone)
A hormone that affects heart rate, blood pressure, body temperature, and weight. Thyroid hormone is made by the thyroid gland and can also be made in the laboratory.