What is the effect on stroke volume when a ventricle stretches more at the end of diastole?

When a ventricle stretches more at the end of diastole, this phenomenon is referred to as preload, which is the initial stretching of the cardiac muscle fibers. According to the Frank-Starling law of the heart, the stroke volume (the amount of blood ejected by a ventricle with each heartbeat) increases as the volume of blood filling the heart during diastole increases, up to a certain point. This is because the more the muscle fibers are stretched, the stronger the contraction will be, leading to a greater volume of blood being pumped out during systole.

This relationship highlights how the heart is able to adjust its output based on the volume of blood returning to it. An increased amount of blood in the ventricle at the end of diastole causes a more forceful contraction, thereby increasing the stroke volume. This adaptive mechanism is essential for maintaining adequate blood circulation in response to varying conditions, such as exercise or volume overload.