What is the main function of the heart valves?

The primary function of the heart valves is to prevent the backflow of blood within the heart and the major arteries leading from the heart. Each valve is designed to open and close at specific times during the cardiac cycle, ensuring that blood flows in the correct direction — from the atria to the ventricles and from the ventricles to the arteries, without any reverse flow. This unidirectional flow is crucial for maintaining efficient circulation and overall heart function.

The other options relate to different aspects of cardiovascular function but do not accurately reflect the primary role of the heart valves. For instance, regulating heart rate is primarily controlled by the sinoatrial node and the autonomic nervous system. Supplying oxygenated blood involves the role of the lungs and the overall circulatory system, not just the valves. Lastly, while blood pressure is influenced by many factors within the cardiovascular system, it is not the function of the valves to increase blood pressure; instead, they assist in the efficient flow of blood, which can contribute to maintaining blood pressure levels.