Hi, I’m Dr. Mary Ann Block, Physician, Author and Medical Director of The Block Center in Dallas/Fort Worth, here for About.com. Today, I’ll explain what the thyroid is, what it looks like, and what it does.The thyroid is an organ that sits low in the front of the neck, just below the Adam’s apple - along the front of the windpipe. The gland has a brownish red color, that’s because it’s rich with blood vessels.The thyroid is shaped like a butterfly, with a left and a right part, called lobes. When it’s its normal size, the thyroid is fairly flat, and you probably can’t feel it. But, even though it’s pretty small, it has a very important function.The main job of the thyroid is to help control metabolism and growth of the body. Inside the thyroid are millions of follicles which release thyroid hormones. The main hormones released by the thyroid are triiodothyronine, also known as T3, and thyroxine, also known as T4.But the thyroid doesn’t know how much hormones it needs to release. That’s why it works together with the pituitary gland and the hypothalamus. The hypothalamus sends a signal to the pituitary gland, and the pituitary gland releases a thyroid stimulating hormone to the thyroid gland. It tells the thyroid how much hormone the body needs.When the thyroid functions well, it releases the right amount of thyroid hormones. But when it doesn’t, many parts and functions of the body can be affected.For more on thyroid functions, diseases and treatments, visit health.about.com. Thanks for watching!