Atrioventrikulaariset

Atrioventrikulaariset refers to the atrioventricular valves of the heart. These valves are crucial for the proper unidirectional flow of blood through the cardiac chambers. There are two atrioventricular valves in the human heart. The tricuspid valve is located between the right atrium and the right ventricle, and the mitral valve, also known as the bicuspid valve, is situated between the left atrium and the left ventricle.

During the diastolic phase of the cardiac cycle, when the heart muscle relaxes, the atrioventricular valves open. This allows deoxygenated blood from the body to fill the right atrium and then pass into the right ventricle, and oxygenated blood from the lungs to fill the left atrium and then pass into the left ventricle. As the ventricles begin to contract (systole), the pressure within them rises sharply. This increase in pressure causes the atrioventricular valves to close, preventing the backflow of blood into the atria. Simultaneously, the semilunar valves (aortic and pulmonary valves) open, allowing blood to be pumped out of the ventricles into the pulmonary artery and aorta, respectively.

The proper functioning of the atrioventricular valves is essential for maintaining adequate cardiac output and overall cardiovascular health. Dysfunction of these valves can lead to various cardiac conditions, such as valvular regurgitation (leakage) or stenosis (narrowing), which can impair the heart's ability to pump blood effectively and may require medical intervention. The characteristic "lub-dub" sounds of the heartbeat are primarily produced by the closing of the heart valves, with the "lub" sound corresponding to the closure of the atrioventricular valves.