Karen is taking the medication verapamil, a drug that blocks the calcium channels in cardiac muscle cells. What effect should this medication have on Karen's stroke volume?

Cardiac output cannot increase indefinitely because:

(a) The available filling time decreases as heart rate increases

(b) The heart becomes unable to contract at faster rates

(c) Stroke volume increases too much, leading to overfilling

(d) The heart’s muscle fibers lose their ability to stretch

(e) None of these reasons

Differentiate between stroke volume and cardiac output. How is cardiac output calculated?

What factors influence cardiac output?

The following measurements were made on two individuals (the values recorded remained stable for 1 hour):

Person 1: heart rate, 75 bpm; stroke volume, 60 mL

Person 2: heart rate, 90 bpm; stroke volume, 95 mL

Which person has the greater venous return?

Which person has the longer ventricular filling time?

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

The amount of blood in the ventricles at the end of the ventricular filling phase is the end-systolic volume.

Mr. Watson has been diagnosed with mitral insufficiency, or a malfunctioning mitral valve, which causes the valve to not close properly. Predict the signs and symptoms you might expect from a disease of this valve. What would happen to the patient's stroke volume and cardiac output? Explain. What might help improve his cardiac output?

Two elements determine blood pressure—the cardiac output of the heart and the peripheral resistance, or friction, in the blood vessels. Name two factors that increase cardiac output. Name two factors that increase peripheral resistance.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Tissue perfusion to the heart decreases during systole and increases during diastole.