Venous valve - a very important element of the circulatory system, which ensures the movement of blood towards the heart despite the effects of gravity. By the way, these structures are quite vulnerable. According to statistics, a huge number of people suffer from some form of valvular insufficiency.
Naturally, many readers are interested in additional information. What does a venous valve look like? What is its role in the circulatory system? Why does valve failure develop? Why are these pathologies dangerous? Many people are looking for answers to these questions.
General information on the anatomy of the circulatory system
Before considering questions about how it looks and what functions the venous valve performs, it is worth familiarizing yourself with the general data on the functioning of the circulatory system.
Arterial blood flows from the left ventricle to the aorta, and from there to other arteries, which are directed to organs and tissues, being divided into smaller branches and structures (up to capillaries). During circulation through the capillary network, the blood gives up the available oxygen and collects metabolic products.
Further, blood is collected through the venous capillaries into larger vessels (veins) , which are eventually included in the trunks of the superior and inferior vena cava, which flow into the right atrium.
It is worth noting that veins have a unique structure, which is associated with the peculiarity of their functioning. In particular, the walls of some vessels are "equipped" with special valves that prevent the return flow of blood.
Brief historical background
For the first time, the opinion about the presence of valves was laid out in 1574, in a scientific publication by the Italian surgeon and anatomist Fabrizia.
Nevertheless, the presence of such structures was officially recognized in 1628 thanks to the work of the English physician and physiologist William Harvey. It was the presence of such a structure as a venous valve that made it possible for a specialist to experimentally demonstrate that blood returns through the veins to the atrium (at that time it was believed that the veins carry blood from the heart, and not to it).
Like heart valves, venous structures regulate the blood circulation, directing blood in the right direction. By the way, such valves are not only found in the human body. They have also been found in some animals, including reptiles and amphibians.
Where are the valves located?
It is worth noting that such structures are not in every vessel that carries blood to the heart. For example, valves are absent in large vessels, including the superior and inferior vena cava. Similar structures are rarely present in the common iliac vessels.
The largest number of valves is in the veins of medium and small caliber, including vessels of the upper and lower extremities, the internal jugular, subclavian and external iliac veins.
Venous valve structure
What does a similar structure look like? As a sample, you can take the venous valve of the lower extremities.
Valves are parietal folds of the inner lining of the veins. At the same time, the basis of such a structure is strong collagen tissue. Valves can be single, double or tricuspid and resemble a pocket in shape. Such structures are always open towards the heart, so blood can move up a large circle of blood circulation without any obstacles.
The role of venous valves: how does it work?
Of course, it is worth learning more about how these structures work. As an example, we can take venous valves of the lower extremities of a person.
Blood moves up due to the continuous operation of the muscular-venous pump. The muscles contract, thereby acting on the venous walls, squeezing them and pushing the blood towards the heart. But after this comes a period of muscle relaxation. According to the laws of physics, at this moment the blood should rush down, because the pressure is significantly reduced. But this does not happen due to venous valves.
The valve flaps are filled with blood, stretched and closed by the edges, preventing the movement of blood down.
How does valve insufficiency in veins develop and what is dangerous?
The operation of the valves ensures a healthy state of the venous vessels. Nevertheless, under the influence of certain factors, the valve mechanism begins to work incorrectly. Thus, the insufficiency of the valve system develops, and such a pathology is very dangerous.
Blood begins to move randomly. Not meeting any obstacles in its path, the liquid flows downward, in the direction from the heart. Thus, venous congestion develops. The walls of the vessels slowly but steadily increase in size. Fluid from the blood gradually penetrates into the intercellular space, forming persistent edema. The insufficiency of the valve system leads to the development of varicose veins, thrombosis, phlebitis and other diseases.
The main causes of valvular insufficiency
In fact, there are many reasons for the development of valvular insufficiency. A list of risk factors is worth a look.
- First of all, it is worth mentioning increased physical exertion.
- On the other hand, inactivity is also dangerous. Deficiency of physical activity leads to stagnation of blood in the lower extremities, as a result of which the walls of blood vessels begin to deform and lose elasticity. The process also affects the valve system, which leads to the progression of its failure.
- There is also a genetic predisposition.
- It is worth paying attention to age-related changes in the body. As they age, the walls of the vessels and valves begin to lose elasticity. The veins gradually thin out, and blood flow slows down.
- Valve insufficiency may result from hormonal changes. For example, a similar pathology often develops in women during pregnancy (in addition to hormonal adjustment, an increase in blood volume also takes place), as well as during menopause.
- Risk factors include disorders of the cardiovascular system. Potentially dangerous is considered chronic hypertension.
Methods of treating failure
Therapy of valvular insufficiency largely depends on the form, stage of development, severity of the disease and the causes of its development.
Sometimes patients are prescribed drugs that normalize blood circulation, as well as strengthen the walls of blood vessels. Vitamin therapy is also mandatory (vitamin C has a positive effect on the condition of the veins). If hypertension occurs, then patients take medications to normalize blood pressure. Doctors also recommend regular therapeutic exercises. A useful, and sometimes the only way to maintain blood flow is to wear special compression garments (long socks, stockings).
One of the effective methods is sclerotherapy. This procedure is very popular in Europe. The essence of therapy is simple - a special substance is injected into the affected vein, which causes irritation and a chemical burn of the vessel. Due to this effect, the vein walls stick together - the affected vessel leaves the general bloodstream system.
In the most severe cases, the doctor decides on a surgical procedure. There are many techniques, ranging from ligation of the vessels to the excision of the affected areas of the veins and the formation of new blood collaterals.