1. Chapter 15 Cardiovascular System

2. Size of Heart
Average Size of Heart
14 cm long
9 cm wide

3. Heart Hollow, fist-sized muscular organ
Located slightly to left of body’s midline
Acts as dual pumping system

4. Location of Heart posterior to sternum medial to lungs
anterior to vertebral column
base lies beneath 2nd rib
apex at 5th intercostal space
lies upon diaphragm

5. Coverings of Heart

6. Pericardium Fibrous sac that covers heart 2 portions
Fibrous pericardium-external sac
Tough, white, fibrous tissue; fits loosely around heart
Protects heart & serous membrane
Serous pericardium: internal sac

7. Serous Layer
Serous layer - a smooth inner sac with lubricated surfaces which allow movement
parietal layer - lines the inner surface of the fibrous pericardium
visceral layer - covers the entire surface of the heart
The potential space between the parietal and visceral layers of the serous pericardium is the pericardial cavity.

10. Extent of mediastinum

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12. Heart Wall: Layers
Endocardium
Myocardium
Epicardium

15. Wall of the Heart

16. Wall of the Heart

17. Heart Chambers Right Atrium receives blood from Left Atrium
inferior vena cava
superior vena cava
coronary sinus
Left Atrium
receives blood from pulmonary veins
Right Ventricle
receives blood from right atrium
Left Ventricle
receives blood from left atrium

18. Heart Valves

19. Coronal Sections of Heart

20. Heart Valves
Tricuspid Valve
Pulmonary and Aortic Valve

21. Skeleton of Heart
fibrous rings to which the heart valves are attached

22. Path of Blood Through the Heart

23. Path of Blood Through the Heart

24. Blood Supply to Heart

25. Blood Supply to Heart

26. Angiogram of Coronary Arteries

27. Heart Actions Atrial Diastole/Ventricular Systole
Atrial Systole/Ventricular Diastole
Atrial Diastole/Ventricular Systole

28. Cardiac Cycle Atrial Systole/Ventricular Diastole
blood flows passively into ventricles
remaining 30% of blood pushed into ventricles
A-V valves open/semilunar valves close
ventricles relaxed
ventricular pressure increases

29. Cardiac Cycle Ventricular Systole/Atrial diastole
A-V valves close
chordae tendinae prevent cusps of valves from bulging too far into atria
atria relaxed
blood flows into atria
ventricular pressure increases and opens semilunar valves
blood flows into pulmonary trunk and aorta

30. Heart Sounds Lubb first heart sound occurs during ventricular systole
A-V valves closing
Dupp
second heart sound
occurs during ventricular diastole
pulmonary and aortic semilunar valves closing
Murmur – abnormal heart sound

31. Heart Sounds

32. Cardiac Conduction System

33. Cardiac Conduction & Control
Intrinsic: internally generated control
Extrinsic: control from outside heart
Heart rate controlled by both
A.N.S.: can fine tune heart
S.N.S.-can accelerate heart rate
P.S.-can slow heart rate
Hormones-can influence heart rate ex. epinephrine

34. Atrioventricular Node (A.V.)
Intrinsic Control
Sinoatrial node (S.A)
Atrioventricular Node (A.V.)
Bundle of His
Purkinje Fibers

35. Sinoatrial Node The natural pacemaker of the heart
Location - junction of superior vena cava and right atrium
Impulse for contraction begins at the SA node and are conducted to the AV node by atrial mycardial fibers (internodal tracts)
The SA node is supplied by both divisions of the ANS

36. Atrioventricular Node
Located in lower right interatrial septum
Impulse slows
Slowing allows atria to contract & ventricle to fill with blood

37. Heart with AV node

38. Bundle of His Originates in AV. Node
Divides into left and right branches
Impulse from AV. Continues into left and right bundle branches

39. Purkinje Fibers Connect bundle branches to lateral walls of ventricle
Impulse moves through Purkinje fibers reaching ventricle muscles
Stimulation of ventricle muscles begins in intraventricular septum & moves downward
Depolarization of ventricles & contraction

45. Abnormal EKGs

46. Heart Valves

47. Animation-Flow of blood through heart

48. Cardiac Conduction System

49. Electrocardiogram
recording of electrical changes that occur in the myocardium
used to assess heart’s ability to conduct impulses
P wave – atrial depolarization
QRS wave – ventricular depolarization
T wave – ventricular repolarization

50. Electrocardiogram

51. Electrocardiogram
A prolonged QRS complex may result from damage to the A-V bundle fibers

52. Cardiac Cycle

53. Clinical Application Arrhythmias Ventricular fibrillation Tachycardia
rapid, uncoordinated depolarization of ventricles
Tachycardia
rapid heartbeat
Atrial flutter
rapid rate of atrial depolarization

54. Regulation of Cardiac Cycle
Autonomic nerve impulses alter the activities of the S-A and A-V nodes

55. Regulation of Cardiac Cycle
Additional Factors that Influence HR
physical exercise
body temperature
concentration of various ions
potassium
calcium
parasympathetic impulses decrease heart action
sympathetic impulses increase heart action
cardiac center regulates autonomic impulses to the heart

57. Blood Vessels arteries carry blood away from ventricles of heart
arterioles
receive blood from arteries
carry blood to capillaries
capillaries
sites of exchange of substances between blood and body cells
venules
receive blood from capillaries
veins
carry blood toward ventricle of heart

58. Arteries Artery thick strong wall endothelial lining
middle layer of smooth muscle and elastic tissue
outer layer of connective tissue
Carry blood away from heart
Vascular resistance low
Mean arterial pressure = 100mmHg

59. Artery

60. Arterioles Arterioles thinner wall than artery endothelial lining
some smooth muscle tissue
small amount of connective tissue
helps control blood flow into a capillary
Mean pressure =85mmHg

61. Arteriole smallest arterioles only have a few smooth muscle fibers
capillaries lack muscle fibers

62. Venules Venule thinner wall than arteriole
less smooth muscle and elastic tissue than arteriole
Carry blood away from capillaries to veins
BP 15mmHg when blood returning to heart

63. Veins Vein thinner wall than artery
three layers to wall but middle layer is poorly developed
serves as blood reservoir
Carry blood from venules to heart
have valves =prevent backflow of blood
Mean pressure =less than 15mmHg

64. vein

65. Vein valve

66. Vein, valves & muscle contraction

67. Walls of Artery and Vein

68. Capillaries smallest diameter blood vessels
extensions of inner lining of arterioles
walls are endothelium only; single layer
semipermeable
sinusoids – leaky capillaries
Join arterioles & venules
Vascular resistance low = 35mmHg

69. Capillary Network

71. Exchange in the Capillaries
water and other substances leave capillaries because of net outward pressure at the capillaries’ arteriolar ends
water enters capillaries’ venular ends because of a net inward pressure
substances move in and out along the length of the capillaries according to their respective concentration gradients

72. Venous Valves

73. Characteristics of Blood Vessels

74. Blood Volumes in Vessels

75. Arterial Blood Pressure
Blood Pressure – force the blood exerts against the inner walls of the blood vessels
Arterial Blood Pressure
rises when ventricles contract
falls when ventricles relax
systolic pressure – maximum pressure
diastolic pressure – minimum pressure

76. Pulse
alternate expanding and recoiling of the arterial wall that can be felt

77. Factors That Influence Arterial Blood Pressure

78. Control of Blood Pressure
Controlling cardiac output and peripheral resistance regulates blood pressure

79. Control of Blood Pressure
If blood pressure rises, baroreceptors initiate the cardioinhibitory reflex, which lowers the blood pressure

80. Control of Blood Pressure
Dilating arterioles helps regulate blood pressure

81. Venous Blood Flow not a direct result of heart action dependent on
skeletal muscle contraction
breathing
venoconstriction

82. Pulmonary Circuit
consists of vessels that carry blood from the heart to the lungs and back to the heart

83. Blood Flow Through Alveoli
cells of alveolar wall are tightly joined together
the high osmotic pressure of the interstitial fluid draws water out of them

84. Systemic Circuit includes the aorta and its branches
composed of vessels that lead from the heart to all body parts (except the lungs) and back to the heart
includes the aorta and its branches
includes the system of veins that return blood to the right atrium

85. Major Vessels of Arterial System

86. Abdominal Aorta and Its Major Branches

87. Arteries to Neck, Head, and Brain

88. Cerebral Arterial Circle
Circle of Willis
formed by anterior and posterior cerebral arteries, which join the internal carotid arteries

89. Arteries to Shoulder and Upper Limb

90. Arteries to the Lower Limb

91. Major Vessels of the Venous System

92. Major Veins of the Brain, Head and Neck

93. Veins from the Upper Limb and Shoulder

94. Veins That Drain the Thoracic Wall

95. Veins That Drain the Abdominal Viscera

96. Veins of the Lower Limb and Pelvis

97. Life-Span Changes cholesterol deposition in blood vessels
heart enlargement
death of cardiac muscle cells
increase in fibrous connective tissue of the heart
increase in adipose tissue of the heart
increase in blood pressure
decrease in resting heart rate