<P> `` Ventricular diastole , '' begins when the ventricles starts to relax . At this point , some blood of the previous cycle 's systole is still flowing out of the ventricles through the semilunar valves , due to the inertia of the moving blood column , which overcomes the higher pressure in the aorta / pulmonary trunk with respect to the pressure in the ventricles . This short lasting phase , called `` protodiastole '' ends with the closure of the semilunar valves , producing the second heart sound ( S ) . Now that both the AV valves and the semilunar valves are closed , the ventricles are now closed chambers . Hence , this phase is known as isovolumetric ( also called isovolumic , isometric ) relaxation phase . Then the atrioventricular ( AV ) valves ( the mitral valve and the tricuspid valve ) open , allowing blood to fill the ventricles . This ventricular inflow phase can be sub-divided into the ' first rapid filling phase ' as blood rushes in from the atria as a result of ventricular dilation ; a phase of slow ventricular filling called ' Diastasis ' , and the ' last rapid filling phase ' due to atrial contraction ( systole ) . </P>
<P> `` Ventricular diastole , '' begins when the ventricles starts to relax . At this point , some blood of the previous cycle 's systole is still flowing out of the ventricles through the semilunar valves , due to the inertia of the moving blood column , which overcomes the higher pressure in the aorta / pulmonary trunk with respect to the pressure in the ventricles . This short lasting phase , called `` protodiastole '' ends with the closure of the semilunar valves , producing the second heart sound ( S ) . Now that both the AV valves and the semilunar valves are closed , the ventricles are now closed chambers . Hence , this phase is known as isovolumetric ( also called isovolumic , isometric ) relaxation phase . Then the atrioventricular ( AV ) valves ( the mitral valve and the tricuspid valve ) open , allowing blood to fill the ventricles . This ventricular inflow phase can be sub-divided into the ' first rapid filling phase ' as blood rushes in from the atria as a result of ventricular dilation ; a phase of slow ventricular filling called ' Diastasis ' , and the ' last rapid filling phase ' due to atrial contraction ( systole ) . </P>
when are the av and semilunar valves both closed
when are the av and semilunar valves both closed
isovolumetric ( also called isovolumic , isometric ) relaxation phase
isovolumetric ( also called isovolumic , isometric ) relaxation phase