Which best explains most of the effects of hyperthyroidism on the cardiovascular system?
A)compensatory increased activity by the parasympathetic nervous system
B)compensatory decreased activity by the sympathetic nervous system
C)up-regulation of beta-adrenergic receptors by thyroid hormone
D)decreased utilization of iodine consequently leaving largely unused amounts in the bloodstream
E)destruction of adrenergic receptors by high levels of circulating thyroxine

Question

Quizplus · Accepted Answer

Hyperthyroidism results in up-regulation of beta-adrenergic receptors by thyroid hormone, leading to an increase in heart rate, contractility, and cardiac output. This is due to the increased sensitivity of the heart to sympathetic stimulation.

Which Best Explains Most of the Effects of Hyperthyroidism on the Cardiovascular