The venous valve is a very important element of the circulatory system, which ensures the movement of blood towards the heart in spite of 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 valvular insufficiency develop? Why are such pathologies dangerous? Many people are looking for answers to these questions.
General information about the anatomy of the circulatory system
Before considering questions about what a venous valve looks like and what functions it performs, you should familiarize yourself with general data on the functioning of the circulatory system.
From the left ventricle, arterial blood enters the aorta, and from there - to other arteries that go to organs and tissues, dividing 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, the 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 the 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 backflow of blood.
Brief historical background
The first opinion about the presence of valves was published in 1574, in a scientific publication by the Italian surgeon and anatomist Fabricius.
Nevertheless, the existence 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 the 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 the valves in the heart, venous structures regulate the process of blood circulation, directing blood in the right direction. By the way, such valves are not only 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 not every vessel that carries blood to the heart has such structures. For example, valves are absent in large vessels, including the superior and inferior vena cava. Similar structuresrarely present in common iliac vessels.
Medium to small caliber veins have the most valves, including the vessels of the upper and lower extremities, the internal jugular, subclavian and external iliac veins.
The structure of the venous valve
What does such a structure look like? The venous valve of the lower extremities can be taken as a sample.
Valves are parietal folds of the inner lining of the veins. At the same time, the basis of such a structure is a strong collagen tissue. Valves can be one-, two- and three-leaf and resemble a pocket in their shape. Such structures are always open towards the heart, so blood can move up through the systemic circulation without any obstruction.
The role of venous valves: how does it work?
Of course, it's worth learning more about how these structures work. An example is the venous valves of the human lower extremities.
Blood moves up thanks to the continuous work of the musculo-venous pump. Muscles contract, thereby acting on the venous walls, squeezing them and pushing blood towards the heart. But after that 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 precisely because of the venous valves.
Valve leaflets fill with blood, stretch and close at the edges,preventing the blood from flowing down.
How does valvular insufficiency develop and why is it dangerous?
The operation of the valves ensures the he althy condition of the venous vessels. However, under the influence of certain factors, the valve mechanism begins to work incorrectly. This is how the insufficiency of the valve system develops, and such a pathology is very dangerous.
The blood starts to move randomly. Encountering no obstacles on its way, the fluid flows down, in the direction from the heart. Thus, venous congestion develops. The walls of blood vessels slowly but steadily increase in size. Fluid from the blood gradually penetrates into the intercellular space, forming a persistent edema. Insufficiency of the valve system leads to the development of varicose veins, thrombosis, phlebitis and other diseases.
Main causes of valvular insufficiency
In fact, there are many causes of valvular insufficiency. The list of risk factors is worth reading.
- First of all, it is worth mentioning the increased physical activity.
- On the other hand, hypodynamia is also dangerous. Lack 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 insufficiency.
- There is also a genetic predisposition.
- It is worth paying attention to agechanges in the body. As we age, the walls of blood vessels and valves begin to lose elasticity. The veins gradually become thinner and the blood flow slows down.
- Valve insufficiency can be the result of hormonal changes. For example, such a pathology often develops in women during pregnancy (in addition to hormonal changes, there is also an increase in blood volume), as well as during menopause.
- Risk factors include disorders of the cardiovascular system. Chronic hypertension is considered potentially dangerous.
Methods for treating deficiency
Therapy for 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 underwear (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 chemical burns of the vessel. Due to this effect of the vein wallstick together - the affected vessel leaves the general blood circulation system.
In the most severe cases, the doctor decides on surgery. There are many techniques, ranging from ligation of blood vessels to excision of the affected areas of the veins and the formation of new blood collaterals.
