por Dra. Ángeles Herráiz
|Dra. Ángeles Herráiz es Licenciada en Medicina y Cirugía por la Universidad Complutense de Madrid en su especialidad de medicina estética.|
In the aetiology of varicose veins, we can mention various factors: bipedestation, heredity, gender –more frequent among women--, menstrual period, pregnancy, obesity, menopause and old age.
Veins are six to ten times more elastic than arteries. This fact allows for less resistance to the blood flow. Veins carry a larger volume of blood and oppose less resistance to its flow. On the other hand, terminal arteries, arterioles and capillaries carry only 10% of the blood volume and offer more resistance to the blood flow.
The higher blood pressure takes place at the level of the left auricle, aorta and big trunks. The more the arterial branching, the less pressure. The blood reaches the arterial capillary with 35 mm Hg. When the blood goes out from the venous capillaries it reaches only 25 mm Hg. The blood is received into the veins with a pressure of just 15 mm Hg and drains into the right auricle with the lowest pressure of the circulatory system.
In the veins, there is a structure of venous valves. These are membranes with one end joined to the vessel’s wall and the other free. The free end floats and when it joins the opposite valve’s free end guarantees a fast closing. These valves open or close according to the hemodynamic demands influenced by changes in pressure levels.
Varicose veins are an evolutive degeneration of veins that consists in permanent dilation of the vessel associated to elongation, functional and organic avalvulation and permanent damages in parietal endothelium --the inner layer of the vessel’s wall--.