What is the Thyroid?

The thyroid is a small, butterfly-shaped gland just below the Adam’s apple. This gland plays a very important role in controlling the body’s metabolism, that is, how the body functions. It does this by producing thyroid hormones (T4 and T3), chemicals that travel through the blood to every part of the body. Thyroid hormones tell the body how fast to work and use energy.

The thyroid gland works like an air conditioner. If there are enough thyroid hormones in the blood, the gland stops making the hormones (just as an air conditioner cycles off when there is enough cool air in a house). When the body needs more thyroid hormones, the gland starts producing again.

The pituitary gland works like a thermostat, telling the thyroid when to start and stop. The pituitary sends thyroid stimulating hormone (TSH) to the thyroid to tell the gland what to do.

About 20 million Americans have some form of thyroid disease. Many are undiagnosed or misdiagnosed. No age, economic group, race, or sex is immune to thyroid disease.

The thyroid gland might produce too much hormone (hyperthyroidism), making the body use energy faster than it should, or too little hormone (hypothyroidism), making the body use energy slower than it should. The gland may also become inflamed (thyroiditis) or enlarged (goiter), or develop one or more lumps (nodules).

Fact:Two of the most common thyroid diseases, Hashimoto’s thyroiditis and Graves’ disease, are autoimmune diseases and may run in families.
Fact:Hypothyroidism is 10 times more common in women than in men.
Fact:One out of five women over the age of 75 has Hashimoto’s thyroiditis, the most common cause of hypothyroidism.
Fact:Thyroid dysfunction complicates 5%-9% of all pregnancies.
Fact:About 15,000 new cases of thyroid cancer are reported each year.
Fact:One out of every 4,000 infants is born without a working thyroid gland.