<prompt> The Iodine is transpoed into the thyroid gland by:Active transpoSimple diffusionPinocytosisReceptor-mediated endocytosis  <response>: The active transpo system by which iodine is taken up by the thyroid gland is called the iodide trap. Its effectiveness is sometimes assessed by thyroid: serum ratio TS of iodine concentration. Normally, TS ratio is about 30. The sodium-iodide sympoer NIS is located on the basal aspect of the follicular cell membrane. This sympoer uses Na gradient across the membrane to transpo 1 iodide along with 2 Na into the cytosol of the follicular cell. It is a secondary active transpo; Na-K-ATPase would be required to pump Na out of the cell and maintain the Na 