2. Colloid: Homogeneous secretion of epithelium Acidophilic and Pas(+) iodinated thyroglobulin in colloid Contains iodated Colloid thyroglobulin 3. Formation of Apical vesicle triodothyronine(T3)& containing lodide tetraiodothyronine(T4) thyroglobulin ○ oxidation a.AA→(RER)→ thyroglobulin, secreting granules)→ colloid Mannose incorporation b.odde→( iodide pump)→ iodide oxidation in cytoplasm Thyroglobulin colloid→ bound to synthesis tyrosine residues of thyroglobulin→ Amino acids lodide iodated thyroglobulin 1919 2. Colloid: Homogeneous secretion of epithelium. Acidophilic and PAS (+). Contains iodated thyroglobulin . 3. Formation of triiodothyronine (T 3 ) & tetraiodothyronine (T 4 ): a. AA→ (RER)→ thyroglobulin → (G, secreting granules) → colloid. b. Iodide → (iodide pump) → iodide oxidation in cytoplasm → colloid → bound to tyrosine residues of thyroglobulin → iodated thyroglobulin