the closing of the left av valve occurs near the beginning of isovolumetric relaxation
Heart valve are present to prevent the back flow of blood in the heart. There are four valves present in the heart they are aortic valve, pulmonary valve, tricuspid valve and atrioventricular valve.
Isovolumetric relaxation occurs when the aortic valve closes and mitral valve opens. It produces the second component of the heart beat.
Ventricular systole lasts for 0.3 seconds when both ventricles contract, and blood is forced into the lungs via pulmonary trucks.
Atrial diastole lasts about 0.7 second in which relaxation of the atria occurs and it is filled with blood.
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