In the aorta the heart presses oxidized blood out into the arteries with a certain pressure. As the blood gets further away from the heart, the blood vessels get smaller and the blood pressure drops.
When the de-oxidized blood from the legs returns to the heart after having been through microscopic little blood vessels they return through the veins. The blood moves from the superficial, lightly curved veins of the leg through short, diagonal connective veins to the deeper veins and back to the heart. This, however, happens as a combination of venous valves hindering the return of the blood and the shifting pressure of the muscles to the venous walls. This mechanism is also called the venous pump.
If one stands still for a long period of time without activating the venous pump, the venous pressure can increase to 10 times the normal pressure.
Causes
The venous wall in the superficial veins might be too loose. If the venous valves are damaged, they will not be able to prevent the blood from running back into the legs. Some people are born with too few venous valves. In this case the blood will run backwards and make the pressure rise in the superficial veins. As time goes by they will start to swell out and form varicose veins. Varicose veins might also be caused by other diseases that increase the blood pressure in the veins. Also tumour formations might compress the veins.
A more basic cause for the varicose veins is not fully established. Several theories exist. One of them states that the mucopolysaccharides contained in the venous wall are either wrongly composed or exposed to enzymatic break-down.
There is a theory about the possible involvement of the strain of heavy metals - including mercury seepage from amalgam fillings - in the formation of varicose veins. Cigarettes, for example, contain a lot of cadmium.
Varicose veins can appear in all the places in which the blood pressure of a vein gets too high. It might be in the veins in the gullet or in the rectum where they are called haemorrhoids. Varicose veins in the legs is a quite common suffering and they can start to form as early as in your 20s. More people get them with age, however, and women are affected four times as often as men. The varicose veins often come in connection with pregnancy but often disappear a few months after giving birth. Women who have given birth several times, however, increase their risk of permanent varicose veins. It has not been established whether the varicose veins in pregnant women are caused by the increased level of the hormone progesteron, the uterus' pressure on the veins of the pelvis, or a combination of both.
Complications
There are not necessarily symptoms connected with varicose veins. Many people, however, are bothered by the sight of them. If they are pressed, they can sometimes be sore. If they get big enough they can produce an annoying sensation of heaviness in the legs and cause cramps. When the blood supply to the legs is decreased, the tissue does not get enough oxygen and nutrition which causes the skin to discolour and increases the risk of badly healing shin wounds. If a varicose vein is perforated it can cause quite a big bleeding.
Defects of the venous valves in the deeper veins can cause more serious complications, e.g. inflammation of the vessels or an embolus that gets stuck in the lungs.
