Arteries are blood vessels that carry blood away from the heart. They have thick walls composed of three layers: the tunica intima, tunica media, and tunica adventitia. The tunica media is particularly prominent in arteries, containing multiple layers of smooth muscle cells and elastic fibers, allowing them to withstand and regulate high-pressure blood flow. Veins, on the other hand, carry blood back to the heart. Their walls are thinner and less muscular compared to arteries. Veins have a larger lumen and often contain valves that prevent the backflow of blood. The tunica adventitia is the most prominent layer in veins, composed mainly of connective tissue.
