During the cardiac cycle, as ventricular systole is initiated, the pressure inside the ventricles increases. Which of the following sets of valves close immediately to prevent the backflow of blood into the atria?

Step-by-step solution

During the cardiac cycle, the initiation of ventricular systole causes ventricular pressure to increase. This increased pressure forces the closure of the atrio-ventricular (AV) valves to prevent the backflow of blood into the atria. The AV valves are the tricuspid valve (located between the right atrium and right ventricle) and the bicuspid or mitral valve (located between the left atrium and left ventricle). The semilunar valves close during ventricular diastole, not systole, to prevent backflow from the pulmonar