27. The cardiac cycle is the sequence of events that occur when the heart beats. There are two phases of this cycle: Diastole - Ventricles are relaxed. Systole - Ventricles contract.
30. Cardiac Cycle Diastole Phase SA node contracts. Atria contract. Ventricles fill with more blood. Contraction reaches AV node . Late Diastole Atria and Ventricles are relaxed. Semilunar valves are closed. Atrioventricular valves are open. Ventricles continue to fill with blood. Mid Diastole Ventricles relax. Semilunar valves close. Atrioventricular valves open. Ventricles fill with blood. Early Diastole
31.
32. Contraction passes from AV node to Purkinje fibers and ventricular cells. Ventricles contract. Atrioventricular valves close. Semilunar valves open. Blood is pumped from the ventricles to the arteries. Systole Cardiac Cycle Systole Phase
