Question

An increase in sympathetic stimulation of the heart would increase stroke volume by increasing __________. view available hint(s) an increase in sympathetic stimulation of the heart would increase stroke volume by increasing __________. end diastolic volume heart rate end systolic volume contractility submit

Answer 1

The equation for cardiac output is stroke volume x heart rate whereas stroke volume is the function of contractility. The correct answer is "contractility" is an increase in contractility will increase stroke volume. Sympathetic stimulation will also stimulate an increase in heart rate but this is wrong as an increase in heart rate will not increase the stroke volume but rather the overall cardiac output. The end systolic volume will also be increased by sympathetic stimulation but is unrelated to the stroke volume but rather in the heart rate (increase in heart rate results to decreased filling times leading to increased end systolic volume). End diastolic volume will be decreased as more blood goes out the heart per cycle as stroke volume (and cardiac output) increases.