Semilunar heart valve: structure, location. Semi-lunar Vascular Valves

Semi-lunar valves - their definition is given in this article. In addition, after reading the information below, you can learn about the operation of such valves in the human body, about their structure, about the places in which they are located. Information, no doubt, will be of interest to all who are interested in human anatomy.

Determining the valve

In an organism that is a complex mechanism, there are many adaptations in order to direct the streams in the right direction. Such adaptations are in the heart muscle - they are more complex. They are also located in capacitive vessels of various calibres.

Valve apparatus is a collection of anatomical structures that, when working together, interfere with the reverse (retrograde) movement of blood.

Varieties of heart valves

• The first group is the structures that separate the ventricles and the atria.
• The second group is the valves located at the site of the transition to the aorta and the pulmonary artery trunk, in the zone of the retraction of these vessels from the ventricles of the heart.

Aortic and pulmonary valves have the following structures:

1. Semi-lunar dampers (semilunar valves of the heart).

2. Space between the flaps (inter-flap triangles).

3. Sinuses.

4. Fibrous rings (the existence of which is disputed).

Semi-lunar dampers

Since the semilunar form in these valves has only the dampers entering them, it is correct to call these valves the aortic valve and the semilunar valve of the pulmonary trunk. Both valves have three flaps. The aortic valve has a right, left and rear flaps. And at the valve of a pulmonary trunk instead of a back one - forward.

Dimensions of the flaps differ in people of different ages, there are also individual characteristics. As a rule, the width of the half-moon aortic flaps is wider than the aortic sinuses, and on the contrary, they are smaller. Such a structure promotes their displacement downward and closure of the valve when filling them with blood. In the sinuses of the aorta, the coronary arteries are located.

Semilunar valves are located near the fibrous ring. They are formed by an endocardial fold. There are front, left and right crescent-shaped shutters. Their bottom edges are connected to the ends of the sines. Dampers and sinuses form lunettes. Crescent valves are slightly larger in size than the sinuses of the pulmonary trunk.

Sinuses of the aortic valve and the valve of the pulmonary trunk

Sinuses of the aorta and pulmonary artery are the spaces between each of the semilunar closures and the vessel wall.

The height of the aortic sinuses of adults is 1.7-2 cm, their depth is from 1.5 to 3 mm. Deepening of the sinuses occurs with age. The spaces between the flaps next to each other have the form of triangles, with a base facing the ventricles. Triangles consist of collagen and elastic fibers, they connect the dampers together and form fibrous valve rings.

At the base of the aorta, an oval fibrous structure with three teeth is formed, resembling a crown.

Within the pulmonary trunk, three sinuses are usually distinguished: anterior, left and right. Sometimes there are two sinuses. The sizes of these sinuses differ substantially in different age groups, and also have individual features. In adults, the left sine is 19-32 mm wide, 12-16 mm high, 20-32 mm right, and 10-15 mm wide. The front is 20-30 mm and 10-15 mm, respectively.

Not everyone recognizes the existence of a fibrous structure at the base of the pulmonary trunk.

Valve operation mechanism

The crescent semilunar valve does not allow blood to return to the ventricles.

During the contraction of the heart muscle, the blood in the ventricles moves in two directions: toward the semilunar dampers, and toward the atria. Having reached the atrioventricular valves, blood strikes against them, and the valves slam shut. The pressure in the cavity of both ventricles increases. The pressure on the crescent semilunar valve increases and exceeds that in the aorta and pulmonary artery. The only way out of the blood flow is the flow into the aorta, and from the right ventricle into the pulmonary trunk. In this situation, the valvular valves are closed and the semilunar ones are open.

When the current from the cavity of the left ventricle rushes toward the aorta, this current presses the semilunar flaps against the aortic wall. After the expulsion of blood from the cavity of the ventricle, the sinuses of the aorta collapse. There is a relaxation of the ventricles, and the blood thrown into the arteries tends back to the heart, to the left ventricle. Sinuses of the artery are filled with blood, and the sickle valves of the aorta are covered. Blood does not flow back into the cavity of the ventricle.

The pulmonary semilunar valve also works.

Aortic and pulmonary valves prevent the reverse movement of blood from the large vessels in the cavity of the ventricles at the end of the systole.

Semi-lunar Vascular Valves

In the body there is a kind of semilunar valves, which have a simpler structure than the heart valves, but their function remains the same. These are structures that prevent the retrograde movement of blood.

Semilunar valves are located in some veins (legs, upper limbs), as well as in lymphatic vessels.

The venous system is represented by a network of resistive vessels, the function of which is the transport of blood to the right parts of the heart against gravity. Vessels of the venous system have a less developed muscular membrane than in the arteries. They have different mechanisms of blood supply from the lower parts to the heart. One of the adaptive mechanisms is the presence of semilunar valves.

The valves of the veins have two valves, valve rollers and parts of the vessel wall. Valve structures in a larger number are located in the veins of the legs. For example: a large saphenous vein has up to ten venous valves.

Pathologies

If the integrity or function of the valves is impaired as a result of trauma or inflammation, pathological conditions develop that need to be recognized and start the correct therapy (acute or long-term cardiac inferiority in case of damage to the heart valves).

Known pathology of veins, associated with the disruption of the valves, is varicose leg disease, which is dangerous for its complications (thrombophlebitis, swelling of the legs, blockage of the pulmonary artery). Currently, modern medicine has a number of effective ways to restore normal functioning of the body, in particular, the valves in question. Naturally, in each case an individual approach to the sick person is determined.

Thus, we have examined the functions of the semilunar valves, their role in the overall functioning of the human body, the problems that can cause abnormalities and pathologies associated with the valves.