Thyroid hormones T3 and T4

Thyroid gland is a butterfly shaped small gland in front of your neck, below the Adam’s apple. Thyroid gland produces 2 thyroid hormones as T3 and T4. Thyroid hormones T3 triodothyronine and T4 thyroxine are made up of iodine and protein and secreted by thyroid gland.

T3 and T4 thyroid hormone levels are determined by T3 and T4 blood test. These thyroid blood tests show how good your thyroid gland works.

Thyroid gland is activated by an another hormone TSH which is thyroid stimulating hormone. TSH regulates T3 and T4 levels in your body. Thyroid hormones have so many functions in your body like brain development, body energy producing, heart rate or body temperature.

Thyroid hormones are bound to proteins to travel in your blood, at the same time a little amount of thyroid hormone may be found free (unbound). Total T3 and Total T4 means the thyroid hormones that are bound to proteins. Free form of thyroid hormones in your blood are called free T3 and free T4.

Thyroid hormones T3 and T4 secretion

t3 and t4

Thyroid hormones T3 and T4 are produced and secreted by thyroid gland which is found in front of your neck. TSH is thyroid stimulating hormone and it is secreted by pituitary gland at the base of  brain. TSH is transported to thyroid gland by blood circulation and activates the thyroid gland for thyroid hormone production.

Thyroid gland produces mostly T4 and an amount of T3.  T4 is converted to T3 in liver and thyroid gland because T3 is the more active thyroid hormone and regulates your metabolism.


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