PSL201Y1 Lecture Notes - Lecture 18: Heart Valve, Aortic Valve, Pulmonary Vein
Document Summary
Cardiac cycle: events associated with the flow of blood through the heart during a single complete heartbeat since cardiac cycle involves events of 1 heart beat, so a complete cycle consists of ventricular contraction and relaxation. Two main periods of cardiac cycle systole: ventricle contraction diastole: ventricle relaxation. F-filling, c-contraction, e-ejection, r-relaxation instead of phase 1,2,3,4. Cardiac cycle has 4 phases associated with ventricular filling (phase 1), contraction for phase 2, ejection which is phase 3 and relaxation for phase 4. Blood in 1 direction so in general, av and semilunar valve are never opened together at same time if both valves are opened, then blood can move around in multiple direction. This ejection phase is over when semilunar valve (aortic) closes since if this is closed, there isn"t any more ejection, no way for ventricle to dump that blood to artery since valve closed which marks end of ejection phase.
