sydänventtiilit

Sydänventtiilit, known in English as heart valves, are crucial structures within the heart that ensure unidirectional blood flow. The human heart has four main valves: the tricuspid valve, the pulmonary valve, the mitral valve, and the aortic valve. Each valve consists of leaflets, or cusps, that open and close in a coordinated manner with each heartbeat.

The tricuspid valve is located between the right atrium and the right ventricle, while the mitral valve (also known as the bicuspid valve) is between the left atrium and the left ventricle. These are collectively called atrioventricular valves. The pulmonary valve is situated between the right ventricle and the pulmonary artery, and the aortic valve is between the left ventricle and the aorta. These are known as semilunar valves.

During diastole, the period when the heart muscle relaxes, the atrioventricular valves open to allow blood to fill the ventricles. Simultaneously, the semilunar valves are closed, preventing backflow from the arteries into the ventricles. During systole, the period when the heart muscle contracts, the atrioventricular valves close to prevent blood from flowing back into the atria, and the semilunar valves open to pump blood out into the pulmonary artery and aorta.

Dysfunction of heart valves, known as valvular heart disease, can arise from various causes including infections, rheumatic fever, aging, or congenital defects. These dysfunctions can manifest as either stenosis, where a valve fails to open completely, restricting blood flow, or regurgitation (insufficiency), where a valve does not close properly, allowing blood to leak backward. Both conditions can strain the heart and may require medical intervention, such as medication or surgical repair or replacement.