What does the Thyroid do?
The Thyroid operates as part of a feedback loop involving body parts called the Hypothalamus and the Pituitary gland. First, the hypothalamus sends a signal to your pituitary gland through a hormone called TRH. When your pituitary gland receives this signal, it releases another hormone called TSH to your thyroid gland. Upon receiving TSH, your thyroid releases 2 of its own hormones (T3 and T4), which then enter your bloodstream and affect the metabolism of your heart, liver, muscles, and other organs. Finally, your pituitary gland monitors the level of thyroid hormone in your blood and increases or decreases the amount of TSH released, which then changes the amount of thyroid hormone in your blood.