 The blood travels through two types of conduits in the body: the arteries and the veins. The arteries carry the oxygen-rich blood containing nutritious elements from the lungs to the organs. Once it has taken on cell waste, it returns to the heart then the lungs through the veins.
The blood moves in very different ways in these two cases. In the arteries the blood is under pressure and moves in rhythm with the heartbeats. The arteries also have a wall made of muscles which contract to propel the blood along.
However, in the veins, the blood rises passively. The walls of the veins do not have any muscles.
Their structure can be compared to a "flexible hose pipe' which can collapse passively under the effect of the muscles and distend under the effect of the flow of blood.
Sometimes the blood has difficulty in returning to the heart and that is where the venous disease starts.
How does the blood in the veins flow back up to the heart despite gravity?
This occurs thanks to three pumps:
- The plantar pump (on the sole of the foot): when the foot is placed on the ground, the veins
of the foot are crushed by the weight of the body and
this pressure ejects the blood upwards towards the
heart. This is the first stage in the climb back up
to the heart.
- The muscular pump of the legs: when the leg muscles contract they compress the veins and expel the blood upwards; hence the importance of walking.
- The respiratory pump: finally, breathing in creates a need for air and blood, which completes the blood's climb towards the thorax and the heart. Taking a few deep breaths several times a day is an easy way of improving your venous return!
The venous system is composed of two networks, one just under the skin and the
other one deeper, in the muscles of the leg and the thigh. After irrigating the
tissues, the blood passes through the capillaries to the venicula, then to the
saphenous veins and finally it reaches the broader deep veins, which drain it
off to the heart.
 Venous stasis
VENOUS STASIS is when the return of blood to the heart is accomplished with difficulty: the blood "stagnates". This stagnation results from a dysfunction of the valves due to an inflammation process at the level of the wall. With the inflow of blood, the veins distend. The impression of heaviness you feel is linked to the pressure being put on the walls of the veins!
Varicose veins are distended veins damaged by venous insufficiency.
 Valvular reflux
There are valves, or VALVULA, located every 4-5 centimetres inside the veins. They are an anti reflux system: once the blood has flown back above the valve, it cannot then descend again pulled by gravity. Sometimes the valves function badly. This can be because the vein is distended and the two parts of the valve no longer touch each other, or the valve itself is damaged due to an inflammation at the level of the wall. The blood then circulates the wrong way, descending from the heart to the feet and then flowing inside the leg to towards the surface.
This is called VALVULAR REFLUX.
In a case of venous insufficiency, the blood can flow back from the deep veins to the superficial veins: this overloads them and damages them even further!
This is the vicious circle of varicose veins.
Dr Elkik |