In the process of negative feedback,
A)TSH inhibits thyroid hormone secretion by the thyroid gland
B)thyroid hormone inhibits TSH secretion by the anterior pituitary
C)thyroid hormone directly inhibits further thyroid hormone secretion by the thyroid gland
D)TRH inhibits TSH secretion by the anterior pituitary
E)thyroid hormone and TRH inhibit TSH secretion by the anterior pituitary

Question

Quizplus · Accepted Answer

Negative feedback involves the inhibition of further secretion of a hormone. In the case of the thyroid gland, the hypothalamus releases thyrotropin-releasing hormone (TRH), which stimulates the anterior pituitary to release thyroid-stimulating hormone (TSH). TSH then acts on the thyroid gland to stimulate the secretion of thyroid hormones. However, when the levels of thyroid hormones (T3 and T4) in the blood increase, they directly inhibit the secretion of TSH by the anterior pituitary, leading to a decrease in thyroid hormone production. Therefore, B is the correct choice as it describes how thyroid hormone inhibits TSH secretion by the anterior pituitary, leading to negative feedback regulation.

In the Process of Negative Feedback