1. dr shabeel pn

21. Cardiac Conduction system

26. Cardiac Cycle

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.

28. Image courtesy of MedValet Cardiac Cycle

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

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