1. Series of events that constitute a complete heartbeat
Cardiac Cycle:
Series of events that constitute a complete heartbeat

2. Cardiac Cycle Explained
Khan Academy

3. Cardiac Cycle Diagram

6. Heart Sounds “Lubb” = ventricular contraction; A-V valves close
“Dupp” = ventricular relaxation; pulmonary and aortic valves close

7. Events Atria relax and blood flows in
Chambers fill which increases pressure inside causing A-V valves to open
Blood flows into ventricles (70-80% of entering blood)

8. Events, Cont’d
Atrial walls contract (atrial systole) which pumps the remaining 20-30% of blood into the ventricles
Atrial walls relax (atrial diastole)

9. Events, Cont’d
Ventricles contract (ventricular systole); A-V valves close and blood is pumped out
Ventricles relax (ventricular diastole); A-V valves open