The Thyroid or Thyroid gland is one of the largest endocrine glands in the body. The endocrine system is the system that secretes hormones and regulates the body. The thyroid is located in the lower front part of the neck, near the trachea and below the larynx. It comprises of two lobes connected together by the band of tissue called the isthmus. The thyroid weighs about 18-60 grams and is very light and is larger in men than women but it is bigger in women when pregnant. It looks like a butterfly or bowtie. The thyroid is an important part of the body and it is especially important to teenagers. The thyroid manufactures the hormone that helps control metabolism and growth. To do this the thyroid needs the chemical element called Iodine, there is about 50 milligrams of iodine in our body. Thyroid hormones are released from the gland and travel through the bloodstream to your body's cells. They help control growth and the structure of bones, sexual development and many other body functions. Hormones are important in determining if your body will mature as it should. Thyroid hormones also directly affect how most of your organ's function. So when the thyroid isn't working properly, you can have problems in lots of other parts of your body. The thyroid gland is composed of specialized sacs referred to as follicles. The thyroid follicles are spherical in shape. The cells of the follicles have one function which is to produce thyroglobulin, a precursor to true thyroid hormones. When the thyroid is not secreting hormones, the sacs are filled with thyroglobulin. When the body requires thyroid hormones, the thyroglobulin is broken down to produce the hormones which are secreted into the bloodstream.
The thyroid gland is controlled by the pituitary gland in the brain. The pituitary gland affects the thyroid gland by producing a hormone called thyroid-stimulating hormone (TSH) which prompts the thyroid to release more thyroxine (T4) and tri-iodothyronine...
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