Final answer:
The phase of the cardiac cycle where the ventricles contract and pump blood into the aorta and pulmonary arteries is known as ventricular systole.
Step-by-step explanation:
The phase in the cardiac cycle in which the ventricles contract and send blood out of the heart into the aorta and pulmonary arteries is called ventricular systole.
This phase follows atrial diastole, where the atria are relaxed. During ventricular systole, the rising pressure in the contracting ventricles leads to the closure of the atrioventricular valves (tricuspid and mitral valves) to prevent backflow into the atria. As the pressure within the ventricles surpasses that in the aorta and pulmonary arteries, the semilunar valves (aortic and pulmonary) open, allowing blood to be ejected from the heart. This important process ensures unidirectional blood flow and is crucial for efficient circulation throughout the body.