What is the name of the tissue that keeps blood from flowing backwards and provide pressure for the ventricles to pump?

The tissue that prevents blood from flowing backward and helps maintain pressure in the ventricles is called the heart valves. Specifically, the atrioventricular (AV) valves and semilunar valves play crucial roles in this process. The AV valves (tricuspid and mitral valves) prevent backflow into the atria, while the semilunar valves (pulmonary and aortic valves) prevent backflow into the ventricles after contraction. This ensures efficient blood flow throughout the heart and body.