The four heart valves take on one of the most important tasks in the human blood circulation: they act as valves in the heart, determine the direction of blood flow and ensure an even inflow and outflow of blood between the atrium and the heart chamber as well as the adjacent blood vessels.
What are the heart valves?
The heart has a total of four heart valves, which close the inlets and outlets of the heart chambers. They consist of a fabric equipped with a valve function, which ensures an even flow of blood between the atria and the chambers of the heart during cardiac contraction.
Anatomy & structure
The human heart is divided into two equally sized halves by the cardiac septum and thus consists of a right ventricle and an associated right atrium as well as a left ventricle and a left atrium. Because of their different functionality, the four heart valves are divided into two groups: the pocket valves and the leaflet valves. The pocket valves are located in the right and left halves of the heart, between the heart chamber and the adjacent outflow tract.
The pulmonary valve is located in the left half; it lies between the right ventricle and the pulmonary artery, the pulmonary artery. The so-called aortic valve is located in the right half between the left ventricle and the aorta. The valves located between the atria and the ventricles are called leaflet valves because of their characteristic appearance. The so-called mitral valve is located in the right half of the heart between the left atrium and the left ventricle, while the tricuspid valve is located in the left half of the heart and separates the right atrium from the right ventricle.
Function & tasks
During systole, the blood inflow phase, the oxygen-poor and carbon dioxide-enriched blood passes through the tricuspid valve from the right atrium into the right ventricle. Here it is passed through the pulmonary valve into the pulmonary circulation, where it is enriched with oxygen and the carbon dioxide content is reduced.
The “fresh” blood is now ejected from the lungs into the left atrium and then passes through the mitral valve into the left ventricle. From here, the blood now passes through the aortic valve into the largest body artery and thus into the great bloodstream. During the entire process of systole, the heart valves function like mechanical valves that prevent the blood from flowing back by opening or closing. When the blood flowing in from the two atria fills the left and right ventricles, they contract and the mitral and tricuspid valves are closed so that no blood can flow back into the atria.
Due to the increasing pressure in the heart chambers, the aortas and pulmonary valves are opened, which eject the blood into the respective outflow tract. At the end of the systole, the ventricles are mostly empty, the pressure drops and the aortic and pulmonary valves are closed so that no blood can flow back into the ventricles. At the same time, the mitral and tricuspid valves open again and fill the heart chambers with blood again. The heart valves thus play an irreplaceable role in the human blood circulation: they control the flow of blood through the heart, prevent backflow of the inflowing blood and thus ensure an even supply of all organs.
Diseases
If there is calcification, constriction or leakage in one or more of the four heart valves, this can have significant health consequences. The mostly unspecific and seemingly harmless symptoms of a valvular heart disease such as frequent weakness or dizziness, shortness of breath when exerting little effort, feeling of pressure in the chest and water retention in the legs are often not taken seriously or misinterpreted by those affected, which favors an unnoticed progression of the disease.
The long-term consequence of untreated valvular heart disease is usually heart failure, often with subsequent heart failure. Heart valve disease should therefore be diagnosed and treated as early as possible in order to avoid serious damage to the heart. The most common cause of heart valve disease is the natural wear and tear of the body as the body ages. The valves wear out, calcify or constrict. In this case, there is valve stenosis, i.e. valve constriction.
Here the valve cannot open completely, the blood builds up in front of it and the amount of blood that can be pumped through the body is reduced. In order to continue to supply the body adequately, the heart has to provide a higher pumping capacity, which in the long term leads to cardiac insufficiency. Another disease of the heart valves is valve insufficiency. With this form of defect, the flap can no longer close completely; the backflow of blood is no longer adequately blocked, allowing it to flow back into the chambers.
This reduces the pumping power, and pressure builds up on the heart and lungs. A heart valve defect can occur not only with increasing age, but also as a result of a bacterial infection, rheumatic fever or inflammation of the inner lining of the heart. Congenital heart valve defects, on the other hand, are very rare and only occur in around 3 percent of all people. However, if the heart valve defect is diagnosed in good time, an immediate and nowadays very promising therapy can be initiated, which amounts to a pure drug treatment of the patient's symptoms in the case of a minor defect.
In the case of a serious valve defect in which there is a risk of damage to the heart muscle, an operation is normally advisable, which in the case of valve stenosis can consist of valve rupture caused by a heart catheter and, in the case of valve insufficiency, valve reconstruction or valve replacement by an artificial heart valve. Thanks to the considerable progress made in the field of cardiac surgery, such interventions are very promising nowadays and can even cause an existing cardiac insufficiency to recede completely.
Typical & common heart diseases
- Heart attack
- Pericarditis
- Heart failure
- Atrial fibrillation
- Myocarditis
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