Increasing circulating levels of thyroid hormone heighten the sympathetic nervous system's physiologic response to stimulation. What effect does this have on the cardiac system?
A)Increases stroke volume
B)Decreases cardiac rate
C)Lengthens the QRS interval
D)Decreases blood pressure

Question

Quizplus · Accepted Answer

A)The sensitizing effect of abnormally elevated thyroid hormone levels increases the cardiac rate and stroke volume. As a result, cardiac output and peripheral blood flow increase. The increased cardiac rate would result in a shortened QRS interval. Stimulation of the sympathetic nervous system increases blood pressure.
B)The sensitizing effect of abnormally elevated thyroid hormone levels increases the cardiac rate and stroke volume. As a result, cardiac output and peripheral blood flow increase. The increased cardiac rate would result in a shortened QRS interval. Stimulation of the sympathetic nervous system increases blood pressure.
C)The sensitizing effect of abnormally elevated thyroid hormone levels increases the cardiac rate and stroke volume. As a result, cardiac output and peripheral blood flow increase. The increased cardiac rate would result in a shortened QRS interval. Stimulation of the sympathetic nervous system increases blood pressure.
D)The sensitizing effect of abnormally elevated thyroid hormone levels increases the cardiac rate and stroke volume. As a result, cardiac output and peripheral blood flow increase. The increased cardiac rate would result in a shortened QRS interval. Stimulation of the sympathetic nervous system increases blood pressure.

Increasing Circulating Levels of Thyroid Hormone Heighten the Sympathetic Nervous