Which of the following events does NOT happen during thyroid hormone secretion? A)The follicular cells phagocytize a piece of colloid. B)T₄ and T₃ are subsequently diffused out of the cell into the blood. C) T₄ and T₃ are secreted by exocytosis of the colloid that has been internalized by the follicular cells. D) A greater amount of T₄ is secreted than T₃.

Question

Quizplus · Accepted Answer

The phagocytosis of a piece of colloid by the follicular cells is not a step involved in the secretion of thyroid hormone. The correct steps are: iodine is transported into the follicular cells and added to the tyrosine residues within thyroglobulin to form T3 and T4, which are subsequently diffused out of the cell into the blood. Alternatively, the colloid can be internalized by the follicular cells and the T3 and T4 can be secreted by exocytosis. The relative amounts of T3 and T4 secreted may vary based on the body's needs, but this is not related to the step-by-step process of hormone secretion.

Which of the Following Events Does NOT Happen During Thyroid