1. Blood enters top chambers (atria)
2. Right atrium receives deoxygenated blood from body
3. Left atrium receives oxygenated blood from lungs
4. Atria contract to force blood down into ventricles
5. Valves close to stop blood flowing back out
6. Ventricles contract to force blood out of heart
7. Right ventricle forces deoxygenated blood to lungs
8. Left ventricle forces oxygenated blood to rest of body
9. Valves close to stop blood flowing back in