1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fundamentals of Anatomy & Physiology SIXTH EDITION Frederic H. Martini PowerPoint ® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii Chapter 20, part 2 The Heart

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structural Differences in heart chambers The left side of the heart is more muscular than the right side Functions of valves AV valves prevent backflow of blood from the ventricles to the atria Semilunar valves prevent backflow into the ventricles from the pulmonary trunk and aorta Heart chambers and valves

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.7 Structural Differences between the Left and Right Ventricles Figure 20.7a-c

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.8 Valves of the Heart Figure 20.8a

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.8 Valves of the Heart Figure 20.8b

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Connective tissue fibers of the heart Provide physical support and elasticity Distribute the force of contraction Prevent overexpansion The fibrous skeleton Stabilizes the heart valves Physically isolates atrial from ventricular cells Connective Tissues

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Arteries include the right and left coronary arteries, marginal arteries, anterior and posterior interventricular arteries, and the circumflex artery Veins include the great cardiac vein, anterior and posterior cardiac veins, the middle cardiac vein, and the small cardiac vein Blood Supply to the Heart

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.9 Coronary Circulation Figure 20.9a, b

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.9 Coronary Circulation Figure 20.9c, d

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 20-3 The Heartbeat

11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Two classes of cardiac muscle cells Specialized muscle cells of the conducting system Contractile cells Cardiac Physiology

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.11 An Overview of Cardiac Physiology Figure 20.11

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The conducting system includes: Sinoatrial (SA) node Atrioventricular (AV) node Conducting cells Atrial conducting cells are found in internodal pathways Ventricular conducting cells consist of the AV bundle, bundle branches, and Purkinje fibers The Conducting System Animation: Heart flythrough PLAY

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.12 The Conducting System of the Heart Figure 20.12

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SA node begins the action potential Stimulus spreads to the AV node Impulse is delayed at AV node Impulse then travels through ventricular conducting cells Then distributed by Purkinje fibers Impulse Conduction through the heart

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.13 Impulse Conduction through the Heart Figure 20.13 Animation: Cardiac Activity PLAY

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings A recording of the electrical events occurring during the cardiac cycle The P wave accompanies the depolarization of the ventricles The QRS complex appears as the ventricles depolarize The T wave indicates ventricular repolarization The electrocardiogram (ECG)

18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.14 An Electrocardiogram Figure 20.14a

19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.14 An Electrocardiogram Figure 20.14b