Which valves separate the atria from the ventricles?

The separation of the atria from the ventricles is facilitated by the tricuspid and bicuspid valves, also known as the mitral valves. The tricuspid valve is located between the right atrium and the right ventricle, while the bicuspid (or mitral) valve is positioned between the left atrium and the left ventricle. These valves ensure that blood flows in the correct direction, preventing backflow from the ventricles to the atria during ventricular contraction.

In contrast, the aortic and pulmonary valves are located at the exits of the ventricles, preventing backflow into the heart from the aorta and pulmonary artery, respectively. Semilunar valves specifically refer to the aortic and pulmonary valves, emphasizing their design rather than any separation function between the atria and ventricles. "Cardiac valves" is a broader term that encompasses all heart valves and does not specify their particular functions or locations. The specific action of the tricuspid and bicuspid valves in separating the atria and ventricles is crucial for maintaining efficient blood circulation throughout the heart and into the systemic and pulmonary circuits.