Final answer:
During ventricular systole, the atrioventricular valves are closed and the semilunar valves are open, allowing blood to be pumped out of the heart. During atrial diastole, the atria are relaxed, preparing to receive blood for the next cardiac cycle.
Step-by-step explanation:
The positioning of the valve cusps during ventricular systole and atrial diastole is crucial for the proper functioning of the heart. During ventricular systole, the ventricles contract to pump blood out of the heart. This contraction causes the pressure in the ventricles to increase, resulting in the closure of the atrioventricular valves (tricuspid and mitral valves) to prevent backflow of blood into the atria. At the same time, the increase in pressure opens the semilunar valves (pulmonary and aortic valves) allowing blood to flow into the pulmonary artery and the aorta. Meanwhile, during atrial diastole, the atria are in the relaxation phase, preparing to receive blood from the veins. The atrioventricular valves would be preparing to open once again to allow the next inflow of blood from the atria to the ventricles once ventricular systole ends and ventricular diastole begins.