What effect does decreased venous return have on stroke volume?

Decreased venous return leads to a reduction in the amount of blood that returns to the heart, which directly impacts stroke volume. Stroke volume, the volume of blood ejected by the heart with each beat, is influenced by the preload, which refers to the initial stretching of the cardiac muscle fibers prior to contraction. When venous return decreases, the preload is also reduced, resulting in less blood being available in the ventricles at the end of diastole. This diminished filling reduces the stretch of the heart muscle, ultimately leading to lower force of contraction and, consequently, a decrease in stroke volume. Therefore, the correct answer highlights the physiological relationship between venous return and stroke volume, emphasizing the importance of an adequate return of blood to the heart for optimal cardiac output.