The Thyroid Produces and Secretes 2 Metabolic Hormones o Two principal hormones Thyroxine (4)and triiodothyronine(t Required for homeostasis of all cells Influence cell differentiation, growth, and metabolism Considered the major metabolic hormones because they target virtually every tissue
The Thyroid Produces and Secretes 2 Metabolic Hormones Two principal hormones Thyroxine (T4 ) and triiodothyronine (T3) Required for homeostasis of all cells Influence cell differentiation, growth, and metabolism Considered the major metabolic hormones because they target virtually every tissue
Thyroid-Stimulating Hormone(TSH) o Produced from pituitary Regulates thyroid hormone production, secretion, and growth the sodium-iodide symporter (nis) thyroglobulin tg thyroperoxidase (tpo) e Is regulated by the negative feedback action oft, and t
Thyroid-Stimulating Hormone (TSH) Produced from pituitary Regulates thyroid hormone production, secretion, and growth the sodium-iodide symporter (NIS) thyroglobulin (Tg) thyroperoxidase (TPO) Is regulated by the negative feedback action of T4 and T3
Hypothalamic-Pituitary-Thyroid Axis Negative Feedback Mechanism Hypothalamus TRH Stimulation hibition Pituita Free Hormone Bound Hormone T4 Liver T3 TSH Stimulation Thyroid
Hypothalamic-Pituitary-Thyroid Axis Negative Feedback Mechanism
Regulation of thyroid function ● hPt axon e Wollf-chaikoff effect ● others
Regulation of thyroid function HPT axon Wollf –chaikoff effect others
Biosynthesis of Ta andT3 Dietary iodine(I)ingestion Active transport and uptake of iodide(i) by thyroid gland Oxidation of I and iodination of thyroglobulin(tg) tyrosine residues o Coupling of iodotyrosine residues(mit and dit)to form T and t 3 Proteolysis of Tg with release of T, and t, into the circulation
Biosynthesis of T4 and T3 Dietary iodine (I) ingestion Active transport and uptake of iodide (I- ) by thyroid gland Oxidation of I- and iodination of thyroglobulin (Tg) tyrosine residues Coupling of iodotyrosine residues (MIT and DIT) to form T4 and T3 Proteolysis of Tg with release of T4 and T3 into the circulation