Which statement correctly defines end-systolic volume (ESV)?

• A. The volume of blood in the ventricle at the end of diastole.
• B. The volume of blood ejected during systole.
• C. The volume of blood remaining in the ventricle after systole.
• D. The maximum amount of blood that a ventricle can hold in that cardiac cycle.

Answer: (D)

End-systolic volume is the amount of blood left in a ventricle after it has contracted (systole). After the ventricle finishes ejecting blood, the remaining blood constitutes the end-systolic volume. The volume ejected during systole is the stroke volume, which equals EDV minus ESV. The maximum amount the ventricle can hold in that cycle is the end-diastolic volume, not ESV. In a typical heart at rest, EDV is around 120 mL, ESV about 50 mL, and SV about 70 mL; ESV is influenced by contractility and afterload—greater contractility lowers ESV, while higher afterload raises it.