A. Does not operate in the failing heart
B. Does not operate during exercise
C. Explains the increase in cardiac output that occurs when venous return is increased
D. Explains the increase in cardiac output when the sympathetic nerves supplying the heart stimulated

A. Systolic ejection
B. Isovolumetric relaxation
C. Isovolumetric contraction
D. None of the above

A. Heart rate
B. Peripheral resistance
C. Systolic blood pressure
D. Venous return

A. 30 ml
B. 130 ml
C. 70 ml
D. 5 liters

A. The bundle of His
B. All cardiac muscle
C. The sinoatrial node
D. The cervical ganglion

A. Closure of the aortic and pulmonary valves
B. Opening of the aortic and pulmonary valves
C. Closure of the mitral and tricuspid valves
D. Opening of the mitral and tricuspid valves