Abstract
Thyroid mainly secrets two hormones (thyroxine - T4, and triioothyronine - T3) with identical functions, differing only in the speed and intensity of their actions. Thyroid secretion of these hormones is controlled by thyrotropin or thyroid stimulating hormone (TSH). A low hormone secretion by thyroid, resulting in lower than normal basal metabolism rate, is a condition known as hypothyro…