Semilunærklappene

Semilunærklappene, also known as semilunar valves, are a crucial part of the heart's circulatory system. These valves are located at the exit of the two ventricles, the lower chambers of the heart. There are two semilunar valves: the aortic valve and the pulmonary valve. Each valve consists of three crescent-shaped (semilunar) leaflets or cusps made of fibrous tissue.

The function of the semilunar valves is to prevent the backflow of blood from the major arteries into the ventricles after the ventricles contract. During ventricular systole, when the ventricles squeeze to pump blood out, the semilunar valves open to allow blood to flow into the aorta (from the left ventricle) and the pulmonary artery (from the right ventricle). As the ventricles relax in diastole, the pressure in the arteries becomes higher than in the ventricles, causing the semilunar valves to snap shut. This closure ensures that blood does not return to the ventricles, maintaining unidirectional blood flow through the heart and into the systemic and pulmonary circulation.

Disruptions to the proper functioning of the semilunar valves, such as stenosis (narrowing) or regurgitation (incompetence), can lead to significant cardiovascular problems. These issues can strain the heart, impair its pumping efficiency, and lead to symptoms like shortness of breath, chest pain, and fatigue. Conditions affecting these valves are often diagnosed through echocardiography and can be managed with medication or surgical intervention.