Your thyroid gland is an endocrine gland found in the neck. It is responsible for producing the hormonesthroxine (T4) and triiodothyronine (T3) which are then secreted into the blood. If the thyroid doesn't function correctly it can results in thyroid diseases. Hypothyroidism occurs as a result of an underactive thyroid, while Hyperhyroidism arrises from an overactive thyroid. The thyroid itself is composed of 2 sections: the right lobe and the left lobe. The thyroid is controlled by the pituitary gland situated just under the brain. It monitors levels of T4 and T3 in the body, and secretes appropriate hormones to stimulate the thyroid activities.