Venous valve: role and structure
The venous valve is a very important element of the circulatory system, which ensures blood flow towards the heart in spite of gravity. By the way, these structures are quite vulnerable. As statistics show, a huge number of people suffer from some form of valvular insufficiency.
Naturally, many readers are interested in additional information. What does the venous valve look like? What is its role in the functioning of the circulatory system? Why does the valve failure develop? Than such pathologies are dangerous? Many people are looking for answers to these questions.
General information on the anatomy of the circulatory system
Before considering the questions about what the venous valve looks like and what functions it performs, it is worth reading the 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 are directed to organs and tissues, dividing into smaller branches and structures(
Blood is then collected through the venous capillaries into larger vessels( veins), which eventually enter the trunks of the superior and inferior vena cava, which flow into the right atrium.
It should be noted 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, which prevent the reverse flow of blood.
A Brief Historical Reference
For the first time the opinion about the presence of valves was laid out in 1574, in the scientific publication of the Italian surgeon and anatomist Fabricia.
However, officially the existence of such structures was 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 enabled the expert to demonstrate experimentally that the blood returned through the veins to the atrium( at that time it was believed that the veins carried blood from the heart, and not to it).
Like the heart valves, the venous structures regulate the circulatory process, directing the blood in the right direction. By the way, such valves are available not only in the human body. They have also been found in some animals, including reptiles and amphibians.
Where are the valves located?
It should be noted that such structures are not in every vessel carrying blood to the heart. For example, valves are not present in large vessels, including the upper and lower vena cava. Similar structures are rarely present in common iliac vessels.
The greatest number of valves is available in medium and small caliber veins, including vessels of the upper and lower extremities, internal jugular, subclavian and external iliac veins.
The structure of the venous valve
How does this structure look like? As a sample, you can take the venous valve of the lower extremities.
Valves are wall folds of the inner membrane of veins. The basis of this structure is a strong collagenous tissue. Valves can be one-, two- and three-leaved and resemble a pocket in shape. Such structures are always open in the direction of the heart, so blood can move up the 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, you can take the venous valves of the lower limbs 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 that comes the period of muscle relaxation. According to the laws of physics, at this point the blood should rush down, because the pressure is significantly reduced. But this is not exactly due to venous valves.
Valve flaps are filled with blood, stretched and closed by the edges, preventing the movement of blood down.
How does the insufficiency of valves in veins develop and how dangerous?
The operation of the valves guarantees a healthy state of the venous vessels. Nevertheless, under the influence of certain factors, the valve mechanism starts to work incorrectly. So the insufficiency of the valve system develops, and this pathology is very dangerous.
The blood begins to move erratically. Without encountering any obstacles on its way, the liquid flows down, in the direction from the heart. Thus, venous congestion develops. The walls of the vessels slowly but steadily increase in size. The 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, thromboses, phlebitis and other diseases.
The main causes of valve failure
In fact, there are many reasons for the development of valvular insufficiency. A list of risk factors is worth reading.
- First of all it is worth mentioning the increased physical exertion.
- On the other hand, hypodynamia is also dangerous. Deficiency of physical activity leads to stagnation of blood in the lower extremities, as a result of which the walls of the 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 the age-related changes in the body. As the aging of the vessel walls and valves begin to lose elasticity. The veins gradually thin out, and the blood flow slows down.
- Valve inadequacy can be the result of hormonal changes. For example, a similar pathology often develops in women during pregnancy( in addition to hormonal adjustment, there is an increase in the volume of blood), as well as during menopause.
- Risk factors include cardiovascular disorders. Potentially dangerous is considered chronic hypertension.
Methods for treating
deficiency Valve failure is largely dependent 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 strengthening walls of blood vessels. Obligatory is also vitamin therapy( on a condition of veins Vitamin C has a positive effect).If there is hypertension, then patients take medication to normalize blood pressure. Also, doctors recommend regular curative gymnastics. A useful, and sometimes the only way to maintain blood flow is wearing special compression clothes( long socks, stockings).
One effective technique is sclerotherapy. This procedure is very popular in Europe. The essence of the 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 walls of the vein stick together - the affected vessel exits the general system of blood flow.
In the most severe cases, the doctor decides on a surgical procedure. There are many methods, ranging from vascular dressing and ending with excision of affected areas of veins and the formation of new blood collateral.