Background of thyroid disease Approach to HypothyroidismType Clinical features Thyroid hormone synthesis Hypothalamus Releases Thyrotropin Releasing Hormone (TRH) Pituitary TRH stimulates pituitary to release thyroid stimulating hormone (TSH) to stimulate thyroid gland Thyroid gland Takes up iodide and traps it in thyroid follicular cells Thyroglobulin incorporates iodide to form tetraiodothyronine (T4), also known as thyroxine Thyroglobulin can also incorporate iodide to form 3,5,3′-triiodothyronine (T3) Thyroid releases mainly T4 and some T3 into serum Mainly bound to thyroxine-binding globulin (TBG), transthyretin (TTR) Majority of T3 is produced by peripheral conversion of T4 to T3 Thyroid hormone regulation T4 and T3 bind with receptors on tissues to promote actions Small increase in serum T3 and T4 inhibits TSH release Small decrease in serum T3 and T4 increases TSH production (Next Lesson) Action of thyroid hormones Back to Approach to Hypothyroidism No Comments Comments are closed.
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