The thyroid is a small gland responsible for producing hormones that play a crucial role in many of the body’s systems — from cells and tissues, to organs like the heart, brain, liver, and kidneys. Dysfunction occurs when the thyroid produces either too much or too little thyroid hormone. Either can disrupt healthy functioning of vital organs — leading to a wide range of symptoms. The good news? Once diagnosed and treated, it’s entirely possible to live a normal, healthy life.