What effect does increased venous return have on stroke volume?
What effect does increased venous return have on stroke volume?
The influx of blood back to the heart is known as venous return (VR). Since the cardiovascular system is a closed-loop, the venous return must match cardiac production (CO) when averaged over time under steady-state conditions.
Increased venous return to the heart raises the ventricle's loaded volume, stretching the muscle tissue and raising their preload according to the Frank-Starling mechanism. Since myocyte stretch produces a more vigorous systolic contraction, the Frank-Starling Rule specifies that the left ventricle's stroke volume will rise as the left ventricular volume rises. This causes the ventricular contraction force to increases, allowing the heart to eject the extra blood returned to it. A rise in venous return to the heart corresponds to the rise in cardiac output to the circulatory system in this manner.
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