Thyroid Hormones Flashcards
what are the different thyroid hormones secreted
- Thyroxine (T4)
- Triiodothyronine (T3)
what are T4 and T3 attached to
Both are attached to proteins called globulins. This restricts both hormones from diffusing directly into any cell throughout the body.
how are T4 and T3 made
Both hormones are produced in the thyroid using “trapped iodine” from food, water and the amino acid tyrosine.
how do T3 and T4 unbind from their partner proteins
An enzyme will break the bond between the hormone and protein allowing T3 to T4 to diffuse into the cell.
why can T3 and T4 be associated with acting as steroid hormones
Both thyroid hormones work like steroid hormones as they are lipid-loving and hydrophobic.
why are T3 and T4 not classified as steroid hormones if they work like them
Due to their chemical makeup.
what are the five functions of T3 and T4
- Stimulates heart rate and contraction
- Stimulates the synthesis of proteins and carbohydrates
- Influence mood or behaviour
- Increases respiratory rate
- Increase metabolic rate