Select the Statement That Best Explains the Chemical Process That

question 18

Multiple Choice

Select the statement that best explains the chemical process that leads to the physiological development of a goiter.

• A) The hypothalamus secretes TRH (thyrotropin-releasing hormone), which travels to the anterior pituitary. The anterior pituitary is then stimulated to secrete TSH (thyroid-stimulating hormone) into the bloodstream. TSH binds to receptors on the plasma membrane of the thyroid gland, stimulating the production of T₃ and T₄.
• B) When thyroid hormone secretion is suppressed, the feedback loop (TRH, TSH) stimulates the thyroid to secrete more T₃ and T₄. When little or no T₃ and T₄ circulates in the blood, TSH continues to stimulate the thyroid gland to release hormones that it cannot produce. This constant stimulation of the thyroid results in the development of the goiter.
• C) The hypothalamus secretes TRH (thyrotropin-releasing hormone), which stimulates the incorporation of iodide into tyrosine and the condensation of monoiodotyrosine and diiodotyrosine, causing the thyroid to overproduce T₃ and T₄. This constant stimulation of the thyroid results in the development of the goiter.
• D) None of these are correct.