What factors influence cardiac output?

Cardiac output is equal to the:

(a) Difference between the end-diastolic volume and the end-systolic volume

(b) Product of heart rate and stroke volume

(c) Difference between the stroke volume at rest and the stroke volume during exercise

(d) Stroke volume less the end-systolic volume

(e) Product of heart rate and blood pressure

What three factors regulate stroke volume to ensure that the left and right ventricles pump equal volumes of blood?

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?

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?

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?

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?