Basics of Thyroid Function

The Basics of Normal Thyroid Function

Thyroid function is controlled by the communication among three parts of the body: the hypothalamus, the pituitary, and thyroid gland itself (see Figure). This interaction, known as the hypothalamic-pituitary-thyroid axis, functions to maintain normal thyroid levels similar to how a thermostat maintains the temperature. The endocrinologists at Houston Thyroid and Endocrine Specialists believe if patients with hypothyroidism and hyperthyroidism understand how this axis works normally, then the intricacies of thyroid diseases, specifically the treatment of hypothyroidism and the treatment of hyperthyroidism will make more sense. The doctors, who are located in the Texas medical center will spend the time to teach each patient how this system works.

The hypothalamus communicates with the pituitary with a hormone called thyroid releasing hormone (TRH) which tells the pituitary to promote thyroid hormone production. The pituitary communicates with the thyroid gland with thyroid stimulating hormone (TSH) which asks the thyroid to produce thyroid hormones which control the rate of many processes in the body. There are two major thyroid hormones which are named thyroxine (T4) and tri-iodothyronine (T3). T4 and T3 communicate back to both the hypothalamus and the pituitary to stop production of both TRH And TSH. Thus, there is delicate balance between the thyroid hormones and the brain to keep the body healthy.