What is thyroid and what does it do?
Thyroid is a butterfly-shaped gland located in the front of the neck just below the Adam’s apple. The gland wraps around the windpipe (trachea) and has a shape that is similar to a butterfly formed by two wings (lobes) and attached by a middle part (isthmus). The thyroid gland works like a tiny factory that uses iodine (mostly from the diet in foods such as seafood and salt) to produce thyroid hormones. These hormones help regulate the body’s metabolism and affects processes, such as growth and other important functions of the body.
The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3), representing 99.9 percent and 0.1 percent of thyroid hormones, respectively. The hormone with the most biological power is actually T3. Once released from the thyroid gland into the blood, a large amount of T4 is converted to T3 — the active hormone that affects the metabolism of cells throughout our body.
Thyroid hormone regulation — the chain of command
The thyroid itself is regulated by another gland located in the brain, called the pituitary, which secrete Thyroid Stimulationg Hormone ( TSH). In turn, the pituitary is regulated in part by the thyroid (via a “feedback” effect of thyroid hormone on the pituitary gland)
Millions of people in the US have thyroid diseases. Most of them are women. If you have a thyroid disease, your body uses energy more slowly or quickly than it should. A thyroid gland that is not active enough, called hypothyroidism, is far more common. It can make you gain weight, feel fatigued and have difficulty dealing with cold temperatures. If your thyroid is too active, it makes more thyroid hormones than your body needs. That condition is hyperthyroidism. Too much thyroid hormone can make you lose weight, speed up your heart rate and make you very sensitive to heat.
There are many causes for both conditions. Treatment involves trying to reset your body’s metabolism to a normal rate.
