What percentage of blood moves into the ventricles during the rapid filling phase?

During the rapid filling phase of the cardiac cycle, a significant portion of the blood from the atria rushes into the ventricles. This phase occurs immediately after the mitral and tricuspid valves open, allowing blood to flow freely into the ventricles due to the pressure gradient created by atrial contraction.

The correct answer reflects that approximately 70% of the total ventricular filling occurs during this rapid phase. This is a crucial aspect of the cardiac cycle because it highlights how the passive flow of blood contributes to the overall filling of the ventricles before they contract. After this rapid filling phase, the remaining blood volume enters the ventricles during the diastasis and atrial contraction phases, which complete the filling process. Understanding this concept is vital for comprehending the dynamics of heart function and the efficiency of blood circulation in the body.