Full Vein Description
[Continued from above] . . . the body. Veins begin when capillaries merge into venules, the venules into small veins, and the small veins merge into larger ones. They are harder to follow than the arteries, because these vessels are interconnected with irregular networks, so that many small, unnamed venules may join to form a larger vein. On the other hand, larger veins typically parallel the courses taken by named arteries, and the veins are often given the same name as the companion arteries. The veins from all parts of the body (except from the lungs back to the heart) converge into two major paths that lead to the right atrium of the heart. These veins are the superior vena cava and the inferior vena cava.