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Chapter 20, part 1

Chapter 20, part 1. The Heart. Learning Objectives. Describe the organization of the cardiovascular system. Describe the location and general features of the heart, including the pericardium.

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Chapter 20, part 1

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  1. Chapter 20, part 1 The Heart

  2. Learning Objectives • Describe the organization of the cardiovascular system. • Describe the location and general features of the heart, including the pericardium. • Discuss the differences between nodal cells and conducting cells and describe the components and functions of the conducting system of the heart. • Identify the electrical events associated with a normal electrocardiogram.

  3. Learning Objectives • Explain the events of the cardiac cycle including atrial and ventricular systole and diastole, and relate the heart sounds to specific events in the cycle. • Define cardiac output, heart rate and stroke volume and describe the factors that influence these variables. • Explain how adjustments in stroke volume and cardiac output are coordinated at different levels of activity.

  4. SECTION 20-1Organization of the Cardiovascular System

  5. Heart as an Endothermic Organ • Your heart has four chambers (2-cycle pump), and is critical in pumping enough oxygenated blood for you to be able to • 1: Keep a high metabolic rate • 2: Maintain a constant internal temperature, even in cooler environments • 3: Be active under adverse conditions • 4: Process food (get energy) relatively quickly

  6. Two-Cycle Pump—your heart Blue is one cycle (deoxygenated blood) Red is the other Cycle (oxygenated Blood)

  7. The cardiovascular system is divided into two circuits • Pulmonary circuit • blood to and from the lungs • System circuit • blood to and from the rest of the body • Vessels carry the blood through the circuits • Arteries carry blood away from the heart • Veins carry blood to the heart • Capillaries permit exchange

  8. Figure 20.1 An Overview of the Cardiovascular System Figure 20.1

  9. SECTION 20-2Anatomy of the Heart

  10. The pericardia • Visceral pericardium or epicardium • Parietal pericardium • Pericardial fluid

  11. Figure 20.2 The Location of the Heart in the Thoracic Cavity Figure 20.2a, b

  12. Figure 20.2 The Location of the Heart in the Thoracic Cavity Figure 20.2c

  13. Superficial Anatomy of the Heart • The heart consists of four chambers • Two atria and two ventricles • Major blood vessels of the heart include • Inferior and superior vena cavae • Aorta and pulmonary trunk

  14. Figure 20.3 The Superficial Anatomy of the Heart Figure 20.3a

  15. Figure 20.3 The Superficial Anatomy of the Heart Figure 20.3b, c

  16. The Heart Wall • Components of the heart wall include • Epicardium • Myocardium • Endocardium

  17. Figure 20.4 The Heart Wall Figure 20.4

  18. Figure 20.5 The Heart Wall and Cardiac Muscle Cells Figure 20.5a-c

  19. Internal Anatomy and Organization • Atria • Thin walled chambers that receive blood from the vena cavae • Ventricles • Thick walled chambers separated from the atria by AV valves • Chordae tendineae • Tendinous fibers attached to the AV valves • Papillary muscle and trabeculae carneae • Muscular projections on the inner wall of ventricles

  20. Blood flow through the heart • Right atria • Tricuspid valve • Right ventricle • Pulmonary valve • Pulmonary circuit • Left atria • Bicuspid valve • Left ventricle • Aortic valve • Aorta and systemic circuit

  21. Blood Flow in the Heart

  22. Figure 20.6 The Sectional Anatomy of the Heart PLAY Animation: Diagrammatic Frontal Section through the Heart Figure 20.6a, b

  23. Figure 20.6 The Sectional Anatomy of the Heart Figure 20.6c

  24. Heart chambers and valves • 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

  25. Figure 20.7 Structural Differences between the Left and Right Ventricles Figure 20.7a-c

  26. Figure 20.8 Valves of the Heart Figure 20.8a

  27. Figure 20.8 Valves of the Heart Figure 20.8b

  28. Connective Tissues • 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

  29. Blood Supply to the Heart • 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

  30. Figure 20.9 Coronary Circulation Figure 20.9a, b

  31. Figure 20.9 Coronary Circulation Figure 20.9c, d

  32. Heart chambers and valves • 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

  33. Figure 20.7 Structural Differences between the Left and Right Ventricles Figure 20.7a-c

  34. Figure 20.8 Valves of the Heart Figure 20.8a

  35. Figure 20.8 Valves of the Heart Figure 20.8b

  36. Connective Tissues • 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

  37. Blood Supply to the Heart • 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

  38. Figure 20.9 Coronary Circulation Figure 20.9a, b

  39. Figure 20.9 Coronary Circulation Figure 20.9c, d

  40. SECTION 20-3The Heartbeat

  41. Cardiac Physiology • Two classes of cardiac muscle cells • Specialized muscle cells of the conducting system • Contractile cells

  42. Figure 20.11 An Overview of Cardiac Physiology Figure 20.11

  43. The Conducting System • 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 PLAY Animation: Heart flythrough

  44. Figure 20.12 The Conducting System of the Heart Figure 20.12

  45. Impulse Conduction through the heart • 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

  46. Figure 20.13 Impulse Conduction through the Heart PLAY Animation: Cardiac Activity Figure 20.13

  47. The electrocardiogram (ECG) • 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

  48. Figure 20.14 An Electrocardiogram Figure 20.14a

  49. Figure 20.14 An Electrocardiogram Figure 20.14b

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