What is the volume of blood pumped out by a ventricle with each heartbeat?

• A. Stroke Volume
• B. Cardiac Output
• C. Heart Rate
• D. End-systolic volume

Answer: (A)

Stroke volume is the amount of blood ejected by a ventricle with each heartbeat. It is the volume pumped per beat and is calculated as end-diastolic volume minus end-systolic volume. Cardiac output is the total blood pumped per minute and equals stroke volume multiplied by heart rate. Heart rate alone tells you how many beats occur per minute, not how much blood is ejected with each beat. End-systolic volume is the amount remaining in the ventricle after contraction, not the amount that was pumped out. In a typical resting adult, stroke volume is about 70 mL per beat, reflecting the per-beat ejection.