The thyroid gland is the largest endocrine gland of the human body. It is a bilobed gland connected by an isthmus. It is located at the front of the neck, below Adam's apple. Triiodothyronine (T3) and thyroxine (T4) are the two hormones which help to increase the metabolic rate and accelerate the process of protein synthesis. The TSH hormones secreted by the anterior pituitary regulates its function.