What is the primary role of veins?

Veins primarily function to transport blood back to the heart. This role is crucial for maintaining proper circulation within the body. After the arteries deliver oxygen-rich blood to the body's tissues, the veins collect the deoxygenated blood and return it to the heart, where it can then be sent to the lungs for re-oxygenation. The structure of veins, including the presence of valves, supports this function by ensuring that blood flows in the correct direction, preventing backflow. This is in contrast to arteries, which carry blood away from the heart. Understanding the specific roles of veins helps to clarify their importance in the overall circulatory system.