Anatomy and Organization of the Cardiovascular System

1. 4 Unit Fluids and Transport

2. Chapter 20: The Heart

3. How are the cardiovascular system and heart organized?

4. Organization of the Cardiovascular System PLAY The Heart: Anatomy Figure 20–1

5. The Pulmonary Circuit • Carries blood to and from gas exchange surfaces of lungs

6. The Systemic Circuit • Carries blood to and from the body

7. Alternating Circuits • Blood alternates between pulmonary circuit and systemic circuit

8. 3 Types of Blood Vessels • Arteries: • carry blood away from heart • Veins: • carry blood to heart • Capillaries: • networks between arteries and veins

9. Capillaries • Also called exchange vessels • Exchange materials between blood and tissues • Dissolved gases, nutrients, wastes

10. 4 Chambers of the Heart • 2 for each circuit: • left and right: • ventricles and atria

11. 4 Chambers of the Heart • Right atrium: • collects blood from systemic circuit • Right ventricle: • pumps blood to pulmonary circuit

12. 4 Chambers of the Heart • Left atrium: • collects blood from pulmonary circuit • Left ventricle: • pumps blood to systemic circuit

13. Where is the heart located and what are its general features?

14. Anatomy of the Heart • Located directly behind sternum InterActive Physiology: Cardiovascular System: Anatomy Review: The Heart PLAY Figure 20–2a

15. Anatomy of the Heart • Great veins and arteries at the base • Pointed tip is apex Figure 20–2c

16. Relation to Thoracic Cavity Figure 20–2b

17. Relation to Thoracic Cavity • Surrounded by pericardial sac • Between 2 pleural cavities • In the mediastinum

18. What is the structure and function of the pericardium?

19. The Pericardium • Double lining of the pericardial cavity Figure 20–2c

20. 2 Layers of Pericardium • Parietal pericardium: • outer layer • forms inner layer of pericardial sac • Visceral pericardium: • inner layer of pericardium

21. Structures of Pericardium • Pericardial cavity: • Is between parietal and visceral layers • contains pericardial fluid • Pericardial sac: • fibrous tissue • surrounds and stabilizes heart

22. Pericarditis • An infection of the pericardium

23. Superficial Anatomy of the Heart • 4 cardiac chambers Figure 20–3

24. Atria • Thin-walled • Expandable outer auricle

25. Sulci • Coronary sulcus: • divides atria and ventricles • Anterior and posterior interventricular sulci: • separate left and right ventricles • contain blood vessels of cardiac muscle

26. What are the layers of the heart wall?

27. The Heart Wall Figure 20–4

28. 3 Layers of the Heart Wall • Epicardium: • outer layer • Myocardium: • middle layer • Endocardium: • inner layer

29. Epicardium • Visceral pericardium • Covers the heart

30. Myocardium • Muscular wall of the heart • Concentric layers of cardiac muscle tissue • Atrial myocardium wraps around great vessels • 2 divisions of ventricular myocardium

31. 2 Divisions of Ventricular Myocardium • Superficial ventricular muscles: • surround ventricles • Deep ventricular muscles: • spiral around and between ventricles

32. Cardiac Muscle Cells Figure 20–5

33. Cardiac Muscle Cells • Intercalated discs: • interconnect cardiac muscle cells • secured by desmosomes • linked by gap junctions • convey force of contraction • propagate action potentials

34. Characteristics of Cardiac Muscle Cells • Small size • Single, central nucleus • Branching interconnections between cells • Intercalated discs

35. Cardiac Cells vs. Skeletal Fibers Table 20-1

36. What is the path of blood flow through the heart, and what are the major blood vessels, chambers, and heart valves?

37. Internal Anatomy 3D Panorama of the Heart PLAY Figure 20–6a

38. Atrioventricular(AV)Valves • Connect right atrium to right ventricle and left atrium to left ventricle • Permit blood flow in 1 direction: • atria to ventricles The Heart: Valves PLAY

39. Septa • Interatrial septum: • separates atria • Interventricular septum: • separates ventricles

40. The Vena Cava • Delivers systemic circulation to right atrium • Superior vena cava: • receives blood from head, neck, upper limbs, and chest • Inferior vena cava: • receives blood from trunk, and viscera, lower limbs

41. Coronary Sinus • Cardiac veins return blood to coronary sinus • Coronary sinus opens into right atrium

42. Foramen Ovale • Before birth, is an opening through interatrial septum • Connects the 2 atria • Seals off at birth, forming fossa ovalis

43. Pectinate Muscles • Contain prominent muscular ridges • On anterior atrial wall • And inner surfaces of right auricle

44. Cusps • Fibrous flaps that form bicuspid (2) and tricuspid (3) valves • Free edges attach to chordae tendineae from papillary muscles of ventricle • Prevent valve from opening backward

45. Right Atrioventricular(AV)Valve • Also called tricuspid valve • Opening from right atrium to right ventricle • Has 3 cusps • Prevents backflow The Heart: Blood Flow PLAY

46. Trabeculae Carneae • Muscular ridges on internal surface of right ventricle • Includes moderator band: • ridge contains part of conducting system • coordinates contractions of cardiac muscle cells

47. The Pulmonary Circuit • Conus arteriosus (superior right ventricle) leads to pulmonary trunk • Pulmonary trunk divides into left and right pulmonary arteries • Blood flows from right ventricle to pulmonary trunk through pulmonary valve • Pulmonary valve has 3 semilunar cusps

48. Return from Pulmonary Circuit • Blood gathers into left and right pulmonary veins • Pulmonary veins deliver to left atrium • Blood from left atrium passes to left ventricle through left atrioventricular(AV)valve • 2-cusp bicuspid valve or mitral valve

49. The Left Ventricle • Holds same volume as right ventricle • Is larger; muscle is thicker, and more powerful • Similar internally to right ventricle, but does not have moderator band

50. The Left Ventricle • Systemic circulation: • blood leaves left ventricle through aortic valve into ascending aorta • ascending aorta turns (aortic arch) and becomes descending aorta