In Graves’ disease, why doesn’t negative feedback shut off thyroid hormone production before it becomes excessive? Group of answer choices Pituitary TSH (thyroid stimulating hormone) levels are excessive. Hypothalamic TRH (thyroid releasing hormone) levels are deficient Autoantibodies bind to TSH receptor on thyroid gland and stimulate it. There is a deficiency of iodine.
Added by Ralph L.
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Normally, high levels of thyroid hormones (T3 and T4) inhibit the release of TRH from the hypothalamus and TSH from the pituitary gland, reducing stimulation of the thyroid gland and thus decreasing hormone production. Show more…
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Sri K.
Graves' Disease 1. To which of the three classes of hormones do thyroid hormones belong? 2. If a person's diet is low in iodine, predict what happens to thyroxine production. 3. In a normal person, when thyroid hormone levels in the blood increase, will negative feedback increase or decrease the secretion of TSH? 4. In a person with a hyperactive gland that is producing too much thyroid hormone, would you expect the level of TSH to be higher or lower than in a normal person? 5. Why is radioactive iodine (rather than some other radioactive element, such as cobalt) used to destroy thyroid tissue? 6. If levels of TSH are low and thyroxine levels are high, is Graves' disease a primary disorder or a secondary disorder (one that arises as a result of a problem with the anterior pituitary or the hypothalamus)? 7. Antibodies are proteins that bind to the TSH receptor. From that information, what can you conclude about the cellular location of the TSH receptor? 8. In Graves' disease, why doesn't negative feedback shut off thyroid hormone production before it becomes excessive?
The diagram shows the normal feedback loop that controls the production of thyroid hormones in the human body. Graves’ disease is an autoimmune disease in which the body produces autoantibodies to the TSH receptor. When these autoantibodies bind to the receptor, it mimics the action of the TSH hormone. How would the feedback loop and the regulated production of thyroid hormones shown in the diagram be affected in a person with Graves’ disease? a. The feedback loop would be disrupted. Autoantibodies would bind to the TSH receptors, allowing them to continue to produce thyroid hormones. As a result, there would be an overproduction of thyroid hormones because the negative feedback system would be unable to function. b. The feedback loop would be not be disrupted. Autoantibodies would bind to the TSH receptors, allowing them to continue to produce thyroid hormones. As a result, there would be an overproduction of thyroid hormones because the negative feedback system would be unable to function. c. The feedback loop would be disrupted. Autoantibodies would not bind to the TSH receptors, allowing them to continue to produce thyroid hormones. As a result, there would be an overproduction of thyroid hormones because the negative feedback system would be unable to function. d. The feedback loop would be disrupted. Autoantibodies would bind to the TSH receptors, allowing them to continue to produce thyroid hormones. As a result, there would be an overproduction of thyroid hormones because the negative feedback system was functional.
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