1. Chapter 11 The Heart’s Conduction System and The Cardiac Cycle
Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 11 The Heart’s Conduction System and The Cardiac Cycle
Lecture Slides in PowerPoint by Jerry L. Cook
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

2. The Cardiovascular System
A closed system that contains:
4-chambered heart
Blood vessels
Functions of the cardiovascular system:
Deliver oxygen and nutrients to tissues
Remove CO2 and other waste products from tissues

3. Blood Circulation Figure 11.3
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 11.3

4. The Heart About the size of your fist Location
Thoracic cavity between the lungs
Apex pointed toward left hip

5. Visceral pericardium – a membrane lining the outside of the heart
The heart is covered by a double serous (connective tissue) membrane
Visceral pericardium – a membrane lining the outside of the heart
Parietal pericardium – a membrane that lies on the outside of the visceral pericardium
Serous fluid fills the space between the two pericardial membranes

6. The wall of the heart is made of three different types of tissues:
EPICARDIUM
Outside layer of connective tissue (viscera pericardium)
MYOCARDIUM
Middle layer made of cardiac muscle
ENDOCARDIUM
Inner layer made of epithelial tissue (endothelium)

7. The heart’s conduction system is intrinsic – heart muscle cells contract, without nerve impulses, in a regular, continuous way.
Special tissues in the right atrium that set the pace
Sinoatrial Node (SA node)
Natural pacemaker initiates the contraction (heartbeat)
Atrioventricular Node (AV Node)
Delays the impulse briefly to allow atria time to finish contracting

8. The heart’s conduction system is intrinsic – heart muscle cells contract, without nerve impulses, in a regular, continuous way.
Ventricle contracts due to the following fibers (in ventricle wall) working together:
AV bundle
Bundle branches
Purkinje fibers

9. Cardiac Conduction System
Heart Contractions
Cardiac Conduction System
Slide 11.14b
Figure 11.5

10. Cardiac Conduction System
Heart Contractions
Cardiac Conduction System
Slide 11.14b
Figure 11.5

11. Cardiac Conduction System
Heart Contractions
Cardiac Conduction System
Slide 11.14b
Figure 11.5

12. Cardiac Conduction System
Heart Contractions
Cardiac Conduction System
Slide 11.14b
Figure 11.5

13. The Cardiac Cycle
Atria contract simultaneously; atria relax, then ventricles contract.
Systole = ventricle contraction
Diastole = ventricle relaxation

14. Filling of Heart Chambers – the Cardiac Cycle
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 11.6

15. Cardiac Output (CO)
Amount of blood pumped by each side of the heart in one minute
CO = HR x SV *
(heart rate) x (stroke volume)
* Stroke volume = Volume of blood pumped by each ventricle in one contraction

16. Regulation of Heart Rate
Heart Rate INCREASED by:
Sympathetic nervous system – crisis, low blood pressure
Hormones – epinephrine, thyroxine
Exercise
Decreased blood volume

17. 1. The Heart: Regulation of Heart Rate
Heart Rate DECREASED by:
Parasympathetic nervous system
High blood pressure or blood volume
Decreased venous return

18. Cardiac Output Regulation
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 11.7

19. Heart Excitation Related to ECG
Figure 18.17

20. Electrocardiography
Figure 18.16

21. Lub – first sound, resulting from closing of AV valve right after ventricles are filled
Dub – second sound resulting from closure of the Semilunar valve. After which the atria start to fill… and the cycle continues