Keeping the body working right

Thyroid hormones help keep all the cells in the body working right. It does this by controlling the metabolism. This is the rate at which every part of the body functions. The right amount of thyroid hormones keep the metabolism at a healthy pace. This helps the brain, heart, muscles, and other organs work well. A balanced metabolism also helps ensure a healthy temperature, heart rate, energy level, and growth rate. Thyroid hormones also play a vital role in children's growth.

The thyroid-pituitary cycle

The thyroid hormone needs to be kept at a healthy level. A complex cycle maintains this level. The cycle starts with the pituitary gland. This gland checks the thyroid hormone level in the blood.

Depending on the level, the pituitary sends thyroid-stimulating hormone (TSH) through the blood to the thyroid gland. TSH tells the thyroid gland how much thyroid hormone to make. In response to TSH, the thyroid makes thyroid hormone. Then thyroid hormone is sent into the blood to the rest of the body. The pituitary senses the hormone level, adjusts the TSH level, and the cycle continues.