Stroke volume is defined as which of the following?

• A. The total volume of blood in the heart at rest
• B. The amount of blood remaining in the ventricle after contraction
• C. The amount of blood ejected from the ventricle with a single contraction
• D. The rate of blood flow through the aorta

Answer: (C)

Stroke volume is the amount of blood ejected from a ventricle with a single contraction. It equals end-diastolic volume minus end-systolic volume (SV = EDV − ESV). This amount, when multiplied by heart rate, gives cardiac output, the total blood pumped per minute. Stroke volume is influenced by preload (volume entering the heart), afterload (arterial resistance), and contractility (the heart’s pumping strength). The other descriptions refer to different measurements: the total blood in the heart at filling corresponds to end-diastolic volume, the blood left after contraction is end-systolic volume, and the rate of blood flow through the aorta describes cardiac output rather than the amount ejected per beat.