The thyroid gland is a large gland situated in the front part of the neck, just below the adam's apple. It is butterfly-shaped, with the "wings" being the left and right thyroid lobes that wrap around the trachea. Its function is to produce thyroid hormone which is responsible for regulating metabolism and organ function.

The thyroid gland functions in cooperation with the hypothalamus and the pituitary gland. The hypothalamus sends a signal to the pituitary gland through a hormone called TRH (thyrotropin releasing hormone), and the pituitary gland then releases TSH (thyroid stimulating hormone) to the thyroid gland. The thyroid gland then releases T4 and T3 hormones, which enter the bloodstream and affect the metabolism of the heart, liver, muscle and other organs. The pituitary gland regulates the level of thyroid hormone in the blood and increases or decreases the amount of TSH released.

The thyroid gland is prone to several disorders which include:

Hypothyroidism - occurs when the thyroid gland fails to produce enough hormones. This disorder can often go unnoticed, as its symptoms are often indicative of other illnesses. However, once detected, it is easily treated with thyroid replacement hormones.

Hyperthyroidism - occurs when the thyroid gland produces too much hormone, which often calls for the use of radioactive iodine, anti-thyroid drugs, or surgery to slow it down or stop it completely.

Goiters - enlargement of the thyroid gland. These may be removed if they compress the trachea or esophagus, thereby making it hard to breathe or swallow.

Thyroid cancer - This type of cancer is fairly common, but patients have a high rate of long-term survival, and can be easily isolated and treated to prevent it from spreading to other parts of the body.

Thyroid Nodules - These are usually benign, but can indicate thyroid cancer. Treatment sometimes involves a needle biopsy or surgical removal.

Thyroiditis - This is an inflammatory condition within the thyroid gland which often brings about pain and fever and has a wide variety of causes. This condition is easily treatable, and symptoms usually go away on their own.