Thyroxine

Definition

Thyroxine, also known as T4, is a hormone produced by the thyroid gland that plays a crucial role in metabolism and growth. It regulates the rate of energy use and affects nearly every physiological process in the body, including body temperature and heart rate.

5 Must Know Facts For Your Next Test

1. Thyroxine is synthesized from iodine and tyrosine within the thyroid gland.
2. It is converted into triiodothyronine (T3), which is more potent and active in influencing metabolic activities.
3. Thyroxine levels are regulated by thyroid-stimulating hormone (TSH) from the pituitary gland.
4. A deficiency in thyroxine can lead to hypothyroidism, characterized by fatigue, weight gain, and depression.
5. Excessive thyroxine production causes hyperthyroidism, which can result in symptoms like increased heart rate, anxiety, and weight loss.

Review Questions

Related terms

Triiodothyronine (T3): A hormone derived from thyroxine that is more active in regulating metabolism.

Thyroid-Stimulating Hormone (TSH): A hormone produced by the pituitary gland that stimulates the production of thyroxine.

Hypothyroidism:

A condition resulting from insufficient production of thyroid hormones leading to various metabolic slowdowns.