heart valves

Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

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The four heart valves are valves in the heart that ensure orderly blood flow. They are located between the atria and the ventricles of the heart and between the ventricles and the arteries that branch off (the main and pulmonary arteries). Find out here how the heart valves are constructed and function and what health problems they can cause!

What are the heart valves?

The four heart valves are formed by the inner lining of the heart (endocardium). Depending on their construction, there are two types of heart valves: leaflet valves and pocket valves.

Sail flaps

The two leaflet valves (atrioventricular valves, AV valves) are located on the border of the atrium and ventricle. In the left heart this is the bicuspid valve (also mitral valve) with two delicate leaflets, and in the right heart the tricuspid valve with three leaflets. Tendon threads that originate from the papillary muscles (small protrusions on the inner wall of the chamber) attach to the free edges of the cusps. The tendon threads prevent the free edges of the leaflet valves from beating back into the atria during the contraction of the heart chamber (systole). Instead, they are tight against each other and tightly seal the opening to the atrium.

Pocket flaps

The two pocket valves (semilunar valves) are located at the beginning of the two arteries that branch off from the heart chambers: aortic valve and pulmonary valve. They each consist of three crescent-shaped pockets that hang on the inner wall of the artery concerned (aorta or pulmonary artery) and the free edge of which is thickened in the middle. These thickened edges meet when the valves close and seal the opening to the ventricle.

What is the function of the heart valves?

The two leaflet valves (mitral and tricuspid valves) function as inlet valves. The blood that flows into the ventricles from the atria opens and closes them passively and then seals the passage during ventricular systole (i.e. when the ventricles contract) to prevent the blood from flowing back into the atria.

The two pocket valves (aortic and pulmonary valves) function as outlet valves: They prevent the blood previously pressed into the arteries during systole from flowing back into the chambers during the ventricular diastole (i.e. when the chambers relax).

Where are the heart valves?

The bicuspid or mitral valve sits between the left atrium and the left ventricle, the tricuspid valve between the right atrium and the right ventricle.

The aortic valve is located between the left ventricle and the aorta (main artery). The pulmonary valve lies between the right ventricle and the pulmonary artery (Truncus pulmonalis).

What problems can the heart valves cause?

In the case of a congenital or acquired heart valve defect (Vitium), the valve function of a valve is disturbed. There are two types of vitia: stenosis (narrowing) and insufficiency (weakness).

With heart valve stenosis, one of the heart valves is pathologically narrowed. So it cannot open as wide as a healthy door. The blood accumulates in front of the narrowed heart valve, which increases the pressure in the heart cavity concerned. As a result, the wall muscles thicken (hypertrophy). For example, with aortic valve stenosis (aortic stenosis), hypertrophy of the upstream left ventricle occurs.

With heart valve insufficiency, a valve does not close properly. The result is that with each heartbeat, some blood flows back into the upstream heart cavity. This reacts to the increased volume load with an expansion (dilation).

As a mitral valve prolapse, one of the two leaflets or both of the heart valve bulges into the left atrium when the left ventricle is contracted (ventricular systole). The heart valve can still seal tightly or it can leak more or less. Mitral valve prolapse is the most common heart valve change in adults.

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