The morphology of heart valves has long attracted the attention of researchers. Violation of the architectonics or operation of any part of the valve apparatus leads to a violation of the closing function of the valve and pumping activity of the heart as a whole.
General principles of the structure of atrio-ventricular septa
The flap valves contain fibrous rings, cusps, chords, and papillary muscles.
Valvular rings are a fibrous mass with the inclusion of muscle elements, internally coated with the endocardium. The valve flaps are covered with endothelium and have a layered structure.
In the direction from the atrial to the ventricular surface, there are 3 layers:
- Spongy.
- Fibrous.
- Ventricular.
The base of the sash is a fibrous plate, which comes from the fibrous ring.
The flap valves, or rather their spongy layer, is narrow, has many elastic fibers in the connective tissue, which are concentrated mainly along the free edge of the flap. Relatively more elastic fibers in the petals of the bicuspid valve than in the tricuspid.
Collagen fibers predominate in the ventricular layer.
Valve surfaces
The flap valves have two surfaces - atrial and ventricular, and two edges - attached and free.
The area of the atrioventricular valves of male hearts is larger than the area of the same valves in female organs. The tricuspid valve is approximately 25% larger than the bicuspid valve.
Papillary muscles with tendon chords form a subvalvular apparatus of the heart. Chords are attached to the wings. Their length and thickness reaches its maximum by 35-40 years.
Butterfly valve
The number of valves (petals) ranges from 2 to 6. The main ones:
- the front, often one, is sometimes divided into two parts;
- back.
They are always large.
The anterior valve is triangular in shape, attached to the upper medial third, posterior to the rest of the specified valve, it is rectangular in shape. Both have smooth basal and rough apical zones, separated by a ridge.
The anterior lobe of the mitral valve is functionally the main one, it is more mobile, during the systole it has the main load, since it experiences the pressure of the bulk of the blood expelled by the ventricle.
The rear is more involved in closing the valve. Its functional significance is less.
Valve chords are fixed to the papillary muscles.
Tendon Chords:
- woven from the ventricular side of the valves into rough zones, each split into three thinner threads.
5-10 chords are attached to the anterior lobe, which has a 2-leaf valve, from the papillary muscles, 10-20, sometimes 20-30 tendon filaments are attached to the back.
The left atrioventricular opening at the level of the fibrous ring has a slightly oval shape.
3-way valve
Regarding the number of valves (petals) and their sizes in this structure, there is also no consensus. It is generally accepted that it consists of 3 wings and a different number of segments or intermediate valves. With age, the number of petals increases due to the splitting of the main plates into smaller ones.
The valves of the right atrio-ventricular valve are a duplicate of the endocardium that lines the right atrium and ventricle.
The right ventricle, respectively 3 cusps, usually has three groups of papillary muscles. They come from the myocardium of the right ventricle (the anterior one is the most powerful, then the posterior and septum). The number of these muscles, size and shape in people are not the same. Each papillary muscle sends 2-4 chords, which, branching, attach to the lower surface and the edges of the valve cusps. Small intermediate valves are attached to the wall of the ventricle.
Heart valve studies are fundamental.
In recent years, issues of blood supply to valves and their ontogenesis have been clarified.
Thus, in this article, the question of the structure of heart valves, including two- and tricuspid ones, is considered. This information will be useful to students of medical institutions, as well as those who only wish to enroll in this specialty. Moreover, for students studying biology and anatomy, information on what the flaps of the heart is, will also be very interesting.