Stroke volume is defined as what?

• A. The volume of blood in the ventricle at the end of diastole
• B. The volume of blood remaining in the ventricle after systole
• C. The volume of blood pumped per minute
• D. The volume of blood ejected by the ventricle with each heartbeat

Answer: (D)

Stroke volume is the amount of blood the ventricle ejects with each heartbeat. It is the difference between the volume in the ventricle at the end of diastole (when the ventricle is fullest) and the volume remaining after systole (after contraction). For example, if the ventricle fills to 120 mL and leaves 50 mL after contraction, the stroke volume is 70 mL per beat. This is distinct from the volume in the ventricle at the end of diastole or the volume left after systole, and it’s also different from cardiac output, which is the volume pumped per minute (stroke volume times heart rate). Stroke volume reflects how much blood is ejected with each beat and is influenced by preload, afterload, and contractility.