Healthy veins: Insight into a complex system

Veins have the task of transporting oxygen-poor blood back to the heart. They are part of a complex system that runs in our legs, on the one hand superficially, and on the other deep in the muscles. In a healthy person, blood flows from the superficial veins to the deep veins and from the smaller veins to the larger ones. The direction of flow is therefore from the bottom to the top and from the outside to the inside before the blood leaves the leg in the direction of the heart.

Muscles as the motor

Since this return transport runs against the force of gravity, some muscle power is required. The vein wall itself is not equipped to do this. Therefore, the task is taken over by the so-called muscle pump in the foot, calf and thigh. However, it can only function if the vein valves are intact and open and close like valves. In this way, they prevent the backflow of blood with the force of gravity.

From valve to valve

In a healthy leg, blood is transported step by step toward the heart. This is done by pressure and requires that the valves in the veins, which are located one behind the other, close precisely and work together. After each pressure wave, which occurs, for example, when changing position from lying to standing, the blood “falls back” to the next venous valve at the maximum.

Weaknesses in the system

Vein dilation is normal when temperatures rise. The healthy venous system compensates for this phenomenon, so there is no congestion or orthostatic problems. However, it becomes problematic if the dilation is due to weakness in the connective tissue or vein walls. In this case, the venous valves no longer close properly, the blood flows in the wrong direction, “pools” – and eventually accumulates in visible varicose veins.

Learn more:
Varicose veins: A widespread illness and its cause