1. Human Anatomy and Physiology Unit IV Circulation and Body Defense Part II The Heart

2. Resources
Your textbook – Chapter 20 Your lab manual – Exercise 27 and 28 Wiley PLUS

3. Heart Topics Location of the Heart Chambers of the Heart Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output

4. Location of the Heart
The heart is located in the mediastinum, where it is surrounded by a double-layered pericardium

5. Location of the Heart
The heart is located in the mediastinum, where it rests on the diaphragm

6. Location of the Heart
Two-thirds of the heart lies to the left of the midline

7. Location of the Heart

8. Location of the Heart
The heart is enclosed and held in place by the pericardium

9. Location of the Heart Outer fibrous pericardium
Inner serous pericardium
Parietal layer
Visceral layer

10. Pericardium

11. Pericardium
Parietal pericardium
Visceral Pericardium

12. Pericardial Diseases Pericarditis Pericardial effusion
Inflammation of the pericardium
Pericardial effusion
Passage of fluid into the pericardial cavity
Often due to congestive heart failure

13. Pericardial Diseases Cardiac tamponade
Bleeding into the pericardial cavity

14. Pericardial Diseases

15. Heart Topics Location of the Heart Chambers of the Heart Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output

16. Location of the Heart
The wall of the four-chambered heart has three layers: (1) epicardium, (2) myocardium, and (3) endocardium

17. Layers of the Heart Wall
Epicardium Myocardium Endocardium
----- Meeting Notes ( :57) -----
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18. Chambers of the Heart
Right atrium Right ventricle Left atrium Left ventricle

19. Chambers of the Heart
Anterior View
Posterior view

20. Chambers of the Heart
Right atrium and right ventricle pump blood to the lungs

21. Chambers of the Heart
Left atrium and left ventricle pump blood to the rest of the body

22. Coronary Sulci
Coronary sulcus Anterior interventricular sulcus Posterior interventricular sulcus

23. Coronary Sulci
Coronary sulcus Anterior interventricular sulcus Posterior interventricular sulcus

24. Right Atrium Forms the right border of the heart Receives blood from:
Superior vena cava
Inferior vena cava
Coronary sinus

25. Right Atrium Forms the right border of the heart Receives blood from:
Superior vena cava
Inferior vena cava
Coronary sinus

26. Right Atrium In between the atria is the interatrial septum
Fossa ovale

27. Right Atrium Posterior atrial wall is smooth Anterior wall is rough.
Pectinate muscle
Right auricle

30. Right Atrium

31. Right Atrium
Blood leaves the right atrium through the tricuspid valve

32. Right Ventricle
Forms most of the anterior surface of the heart

33. Right Ventricle
Right and left ventricles are separated from each other by the interventricular septum

34. Right Ventricle
The inside of the right ventricle contains muscular ridges called trabeculae carnae

35. Right Ventricle
Blood leaves the right ventricle through the pulmonary semilunar valve
Pulmonary trunk
Right and left pulmonary arteries

36. Left Atrium
Forms most of the base of the heart Receives blood from the pulmonary veins

37. Left Atrium
The left atrium is separated from the right atrium by the interatrial septum

38. Left Atrium
The walls of the left atrium are smooth except for the auricle

39. Left Atrium
Blood leaves the left atrium through the bicuspid valve

40. Left Ventricle
Forms the apex of the heart

41. Left Ventricle Receives blood from the left atrium Bicuspid valve
Chordae tendinae
Papillary muscles

42. Left Ventricle
Blood leaves the left ventricle through the aortic semilunar valve Ligamentum arteriosum

43. Atrial Septal Defects
Incomplete closure of the foramen ovale.

44. Ventricular Septal Defects
Incomplete formation of the interventricular septum.

45. Myocardial Thickness and Function
Atrial walls are thinner than ventricular walls Walls of the right ventricle thinner than walls of the left ventricle

46. Fibrous Skeleton
Four dense connective tissue rings wrapped around the four AV valves of the heart

47. Heart Topics Location of the Heart Chambers of the Heart Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output

48. Heart valves ensure that blood flow is one way
Location of the Heart
Heart valves ensure that blood flow is one way

49. Heart Valves
Left AV valve (bicuspid) Right AV valve (tricuspid) Pulmonary semilunar valve Aortic semilunar valve

50. AV Valves
An AV valve opens towards the ventricle One-way due to pressure gradient Backflow prevented by papillary m. and chordae tendinae

52. SL valves
An SL valve opens towards the artery One-way due to pressure gradient Backflow prevented by shape of valve

54. Heart Murmers
Valve incompetence Valve stenosis

55. Valve Implants

56. Heart Topics Location of the Heart Chambers of the Heart Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output

57. Blood Flow
Systemic circulation Pulmonary circulation

58. Coronary Circulation Lt. coronary a. Rt. coronary a.
Left anterior descending a.
Circumflex a.
Rt. coronary a.
Posterior descending coronary a.

59. Cardiac Veins
Great
Middle
Small
Anterior

60. Athersclerosis

61. Coronary Bypass

62. Heart Topics Location of the Heart Chambers of the Heart Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output

63. Cardiac Muscle
© Jason Taylor

64. Cardiac Muscle
© Jason Taylor

65. Heart Topics Location of the Heart Chambers of the Heart Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output

66. Cardiac Conduction System

67. Action Potentials in Cardiac Cells
Rapid Depolarization Plateau Repolarization Refractory Period

68. The ECG
P Wave QRS Complex T Wave

69. ECG

70. Heart Topics Location of the Heart Chambers of the Heart Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output

71. The Cardiac Cycle
Atrial Systole Ventricular Systole Relaxation Period

72. Atrial Systole
ECG Connection: from P wave to Q wave AV valves: open SL valves: closed

73. Atrial Systole Both atria contract Ventricles are relaxed
Atrial pressure increases
AV valves open
Blood flows into both ventricles
Ventricles are relaxed
Ventricular pressure too low to open SL valves

74. Ventricular Systole Divided into two periods
isovolumetric ventricular contraction
ventricular ejection
Atria are relaxed and filling with blood

75. Isoventricular Ventricular Contraction
ECG Connection: begins with R wave AV valves: closed SL valves: closed

76. Isoventricular Ventricular Contraction
Both ventricles begin contracting
Ventricular pressure increases
AV valves close
Ventricular pressure too low to open SL valves
SL valves remain closed

77. Ventricular Ejection
ECG Connection: from S wave to T wave AV valves: closed SL valves: open

78. Ventricular Ejection Both ventricles continue contracting
Ventricular pressure continues to increase
AV valves remain closed
High ventricular pressure opens SL valves
Blood is ejected into pulmonary trunk and aorta

79. SV= EDV-ESV SV =130 ml – 60 ml SV = 70 ml
Stroke Volume
Stroke volume - the volume of blood ejected from each ventricle during systole.
SV= EDV-ESV SV =130 ml – 60 ml SV = 70 ml

80. Relaxation Period Divided into two periods:
Isovolumetric ventricular relaxation
Passive ventricular filling
Both atria and ventricles are relaxed and filling with blood

81. Isovolumetric Ventricular Relaxation
ECG Connection: begins at end of T wave AV valves: closed SL valves: closed

82. Isovolumetric Ventricular Relaxation
Both ventricles begin to relax
Ventricular pressure begins to decrease
Low ventricular pressure closes SL valves
Ventricular pressure too highto open AV valves

83. Passive Ventricular Filling
ECG Connection: after T wave to next P wave AV valves: open SL valves: closed

84. Passive Ventricular Filling
Both ventricles continue to relax
ventricular pressure continues to decrease
SL valves remain closed
Atrial pressure exceeds ventricular pressure
AV valves open
Blood fills the ventricles

85. Cardiac Cycle and Heart Rate
Durations of atrial and ventricular systole are relatively constant Increased heart rate  decreased relaxation period

86. Heart Topics Location of the Heart Chambers of the Heart Heart Valves
Coronary Circulation
Cardiac Muscle
Cardiac Conduction System
Cardiac Cycle
Cardiac Output

87. Cardiac Output
Cardiac Output (CO) = SV X HR At rest CO = 70 X 75 At rest CO = 5.25 L/minute Cardiac Reserve = 5 X CO CO adjusted by changing SV or HR

88. Regulation of Stroke Volume
Preload Contractility Afterload

89. Preload Increased stretch  increased force of contraction
Increased filling during diastole  increased force of contraction during systole
Determined by:
Duration of ventricular diastole
Venous return

90. Why Preload?
The relationship between ventricular filling (EDV) and preload equalizes the output of the right and left ventricles and keeps the same volume of blood flowing to both systemic and pulmonary circulations.

91. Contractility Positive inotropics increase contraction
Norepinephrine and epinephrine
Negative inotropics decrease contraction
Acetylcholine

92. Afterload
Afterload – the pressure that the ventricles must overcome to open the SL valves. Increased afterload  decreased SV

93. Regulation of Heart Rate
Regulating HR is the body’s principal mechanism of short-term control of CO
Three main mechanisms:
ANS
Endocrine system
Other factors

94. Regulation of Heart Rate - ANS

95. Regulation of Heart Rate - Endocrine
Epinephrine and Norepinephrine Increase HR and contractility Thyroid hormone Increases HR and contractility Cations also affect heart rate: Na+ and K+ decrease HR and contractility Ca2+ increases HR and contractility

96. Regulation of Heart Rate – other factors
Cations also affect heart rate: Na+ and K+ decrease HR and contractility Ca2+ increases HR and contractility

97. EXERCISE AND THE HEART

98. Exercise and the Heart