1. 20.18 The Cardiac Cycle Slide number 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. AV valves opened Semilunar valves closed AV valves closed Semilunar valves closed Semilunar valves closed 4. Diastole: Passive ventricular filling. The AV valves open and blood flows into the relaxed ventricles, accounting for most of the ventricular filling. 3. Diastole: Period of isovolumic relaxation. Blood flowing back toward the relaxed ventricles causes the semilunar valves to close, which is the beginning of ventricular diastole. Note that the AV valves closed, also. 5. Diastole: Active ventricular filling. The atria contract and complete ventricular filling. 2. Systole: Period of ejection. Continued ventricular contraction pushes blood out of the ventricles, causing the semilunar valves to open. 1. Systole: Period of isovolumic contraction. Ventricular contraction causes the AV valves to close, which is the beginning of ventricular systole. The semilunar valves were closed in the previous diastole and remain closed during this period. AV valves opened AV valves closed Semilunar valves opened AV valves closed Semilunar valves closed

2. 20.18 The Cardiac Cycle Slide number 2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Systole: Period of isovolumic contraction. Ventricular contraction causes the AV valves to close, which is the beginning of ventricular systole. The semilunar valves were closed in the previous diastole and remain closed during this period. AV valves closed Semilunar valves closed

3. 20.18 The Cardiac Cycle Slide number 3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Systole: Period of ejection. Systole: Period of isovolumic contraction. AV valves closed Semilunar valves opened AV valves closed Semilunar valves closed

4. 20.18 The Cardiac Cycle Slide number 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Systole: Period of ejection. Continued ventricular contraction pushes blood out of the ventricles, causing the semilunar valves to open. AV valves closed Semilunar valves opened

5. 20.18 The Cardiac Cycle Slide number 5 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diastole: Period of isovolumic relaxation. Systole: Period of ejection. AV valves closed Semilunar valves opened AV valves closed Semilunar valves closed

6. 20.18 The Cardiac Cycle Slide number 6 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diastole: Period of isovolumic relaxation. Blood flowing back toward the relaxed ventricles causes the semilunar valves to close, which is the beginning of ventricular diastole. Note that the AV valves closed, also. AV valves closed Semilunar valves closed

7. 20.18 The Cardiac Cycle Slide number 7 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diastole: Passive ventricular filling. Diastole: Period of isovolumic relaxation. AV valves closed Semilunar valves closed AV valves opened Semilunar valves closed

8. 20.18 The Cardiac Cycle Slide number 8 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diastole: Passive ventricular filling. The AV valves open and blood flows into the relaxed ventricles, accounting for most of the ventricular filling. AV valves opened Semilunar valves closed

9. 20.18 The Cardiac Cycle Slide number 9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diastole: Passive ventricular filling. Diastole: Active ventricular filling. AV valves opened Semilunar valves closed AV valves opened Semilunar valves closed

10. 20.18 The Cardiac Cycle Slide number 10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diastole: Active ventricular filling. The atria contract and complete ventricular filling. AV valves opened Semilunar valves closed

11. 20.18 The Cardiac Cycle Slide number 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diastole: Active ventricular filling. Systole: Period of isovolumic contraction. AV valves opened Semilunar valves closed AV valves closed Semilunar valves closed