Superficial veins are blood vessels located just beneath the skin's surface. They play a crucial role in returning deoxygenated blood from the extremities back to the heart. These veins are often visible and can be seen in areas like the arms and legs. Unlike deep veins, which are located deeper within the body and are surrounded by muscle, superficial veins are more prone to conditions such as varicose veins and thrombophlebitis. Their proximity to the skin makes them important for regulating body temperature through the process of vasodilation and vasoconstriction.