MCAT Question A Day - 6/14/13 - Answer!
End-diastolic volume (EDV) refers to the amount of blood present in the left ventricle after diastole (relaxation). End-systolic volume (ESV) represents the amount of blood in the left ventricle after systole (contraction). What term represents the difference between these two?
A. Cardiac output
B. Heart rate
C. Stroke volume
D. Peripheral resistance
The correct answer is (C). If EDV is the volume of blood in the left ventricle after relaxation (before contraction), and ESV is the volume of blood still in the left ventricle after contraction, then the difference must be the volume that was pumped out of the left ventricle during contraction. This is stroke volume. Cardiac output (choice A) is stroke volume 3 heart rate.
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