How Do Veins Move the Blood?
There are a number of driving forces which are involved in the return of blood to the heart for oxygenation, along the veins. These include the contracting and relaxing effect of muscles in which many veins lie. As muscles work they automatically apply a pumping action to any vein with which they are in touch,and this, because of the vein’s one-way valve system, causes a forward motion of the blood. Many veins run alongside arteries (which carry fresh oxygenated to the body tissues) and the pulsating action of these arteries (due to the heart’s beating) also produces a pump-like effect on the veins. Another key pumping action occurs as we breathe, with the rise and fall of the diaphragm, which creates an alternating positive and negative pressure in the chest cavity. Much of the blood returning to the heart has to overcome the force of gravity, for example as it passes from the feet upwards into the pelvic area and then onto the chest cavity and its destination, the heart. While muscle
