Goiter with normal thyroid function

Thyroid tissue has a strong ability to concentrate iodine. Human thyroid needs 60-80ug of iodine every day to produce physiologically active thyroid hormone. In vivo, there is an interdependent and mutually restrictive feedback relationship between thyroid hormone secreted by thyroid and thyroid stimulating hormone (TSH) secreted by pituitary. In iodine deficiency, thyroid cells cannot synthesize enough thyroid hormone, the concentration of thyroid hormone in blood decreases, the inhibitory effect of thyroid hormone on pituitary secretion (TSH) decreases, the secretion of pituitary TSH increases, the level of TSH in blood increases, resulting in thyroid hypertrophy and hyperplasia.