1. The Cardiovascular System Chapter 11

2. The Cardiovascular System A closed system of the heart and blood vessels The heart pumps blood Blood vessels allow blood to circulate to all parts of the body The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

3. The Heart Location Thorax between the lungs in the inferior mediastinum Orientation Pointed apex directed toward left hip Base points toward right shoulder About the size of your fist

4. The Heart

7. The Heart: Coverings Pericardium—a double-walled sac Fibrous pericardium is loose and superficial Serous membrane is deep to the fibrous pericardium and composed of two layers Visceral pericardium Next to heart; also known as the epicardium Parietal pericardium Outside layer that lines the inner surface of the fibrous pericardium Serous fluid fills the space between the layers of pericardium

8. The Heart: Heart Wall Three layers Epicardium Outside layer This layer is the visceral pericardium Connective tissue layer Myocardium Middle layer Mostly cardiac muscle Endocardium Inner layer Endothelium

9. The Heart: Heart Wall

13. The Heart: Chambers Right and left side act as separate pumps Four chambers Atria Receiving chambers Right atrium Left atrium Ventricles Discharging chambers Right ventricle Left ventricle

14. The Heart: Chambers

15. Differences in Right and Left Ventricles

16. The Heart: Septa Interventricular septum Separates the two ventricles Interatrial septum Separates the two atria

17. The Heart: Septa

18. Systemic and Pulmonary Circulations Systemic circulation Blood flows from the left side of the heart through the body tissues and back to the right side of the heart Pulmonary circulation Blood flows from the right side of the heart to the lungs and back to the left side of the heart

19. Systemic and Pulmonary Circulations Figure 11.3

20. The Heart: Associated Great Vessels Arteries Aorta Leaves left ventricle Pulmonary arteries Leave right ventricle

21. The Heart: Associated Great Vessels Veins Superior and inferior venae cavae Enter right atrium Pulmonary veins (four) Enter left atrium

22. The Heart: Associated Great Vessels

23. Blood Flow Through the Heart Superior and inferior venae cavae dump blood into the right atrium From right atrium, through the tricuspid valve, blood travels to the right ventricle From the right ventricle, blood leaves the heart as it passes through the pulmonary semilunar valve into the pulmonary trunk Pulmonary trunk splits into right and left pulmonary arteries that carry blood to the lungs

24. Blood Flow Through the Heart Oxygen is picked up and carbon dioxide is dropped off by blood in the lungs Oxygen-rich blood returns to the heart through the four pulmonary veins Blood enters the left atrium and travels through the bicuspid valve into the left ventricle From the left ventricle, blood leaves the heart via the aortic semilunar valve and aorta

25. Blood Flow Through the Heart Pump Your Blood

26. Systemic and Pulmonary Circulations Figure 11.3

27. The Heart: Valves Allow blood to flow in only one direction to prevent backflow Four valves Atrioventricular (AV) valves—between atria and ventricles Bicuspid (mitral) valve (left side of heart) Tricuspid valve (right side of heart) Semilunar valves—between ventricle and artery Pulmonary semilunar valve Aortic semilunar valve

28. The Heart: Valves

29. AV valves Anchored in place by chordae tendineae (“heart strings”) Open during heart relaxation and closed during ventricular contraction Semilunar valves Closed during heart relaxation but open during ventricular contraction Notice these valves operate opposite of one another to force a one-way path of blood through the heart

30. Figure 11.5a, step 1 Blood returning to the atria, puts pressure against AV valves; the AV valves are forced open Ventricles Operation of the AV valves AV valves open (a)

31. Figure 11.5a, step 2 Blood returning to the atria, puts pressure against AV valves; the AV valves are forced open As the ventricles fill, AV valve flaps hang limply into ventricles Ventricles Operation of the AV valves AV valves open (a)

32. Figure 11.5a, step 3 Blood returning to the atria, puts pressure against AV valves; the AV valves are forced open As the ventricles fill, AV valve flaps hang limply into ventricles Atria contract, forcing additional blood into ventricles Ventricles Operation of the AV valves AV valves open (a)

33. Figure 11.5a, step 4 Ventricles contract, forcing blood against AV valve flaps (a)

34. Figure 11.5a, step 5 Ventricles contract, forcing blood against AV valve flaps AV valves close AV valves closed (a)

35. Figure 11.5a, step 6 Ventricles contract, forcing blood against AV valve flaps AV valves close Chordae tendineae tighten, preventing valve flaps from everting into atria AV valves closed (a)

36. Figure 11.5b, step 1 As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open Aorta Pulmonary trunk Semilunar valve open Operation of the semilunar valves (b)

37. Figure 11.5b, step 2 As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open Aorta Pulmonary trunk Semilunar valve open Semilunar valve closed As ventricles relax, and intraventricular pressure falls, blood flows back from arteries, filling the leaflets of semilunar valves and forcing them to close Operation of the semilunar valves (b)

38. Coronary Circulation Blood in the heart chambers does not nourish the myocardium.

39. Coronary Circulation The heart has its own nourishing circulatory system consisting of Coronary arteries—branch from the aorta to supply the heart muscle with oxygenated blood Cardiac veins—drain the myocardium of blood Coronary sinus—a large vein on the posterior of the heart, receives blood from cardiac veins Blood empties into the right atrium via the coronary sinus

40. The Heart: Conduction System Intrinsic conduction system (nodal system) Heart muscle cells contract, without nerve impulses, in a regular, continuous way

41. The Heart: Conduction System Special tissue sets the pace Sinoatrial node = SA node (“pacemaker”), is in the right atrium Atrioventricular node = AV node, is at the junction of the atria and ventricles Atrioventricular bundle = AV bundle (bundle of His), is in the interventricular septum Bundle branches are in the interventricular septum Purkinje fibers spread within the ventricle wall muscles

42. Heart Contractions

43. Contraction is initiated by the sinoatrial node (SA node) Sequential stimulation occurs at other autorhythmic cells Force cardiac muscle depolarization in one direction—from atria to ventricles

44. Heart Contractions Once SA node starts the heartbeat Impulse spreads to the AV node Then the atria contract At the AV node, the impulse passes through the AV bundle, bundle branches, and Purkinje fibers Blood is ejected from the ventricles to the aorta and pulmonary trunk as the ventricles contract Your Heart’s Electrical System

45. Heart Contractions

46. Tachycardia—rapid heart rate over 100 beats per minute Bradycardia—slow heart rate less than 60 beats per minutes

47. Heart Contractions

48. Contraction is initiated by the sinoatrial node (SA node) Sequential stimulation occurs at other autorhythmic cells Force cardiac muscle depolarization in one direction—from atria to ventricles

49. Heart Contractions Once SA node starts the heartbeat Impulse spreads to the AV node Then the atria contract At the AV node, the impulse passes through the AV bundle, bundle branches, and Purkinje fibers Blood is ejected from the ventricles to the aorta and pulmonary trunk as the ventricles contract Your Heart’s Electrical System

50. Heart Contractions

51. Tachycardia—rapid heart rate over 100 beats per minute Bradycardia—slow heart rate less than 60 beats per minutes

52. Heart Diseases/Disorders Stable angina chest pain or discomfort that typically occurs with activity or stress caused by poor blood flow through the blood vessels (coronary vessels) of the heart muscle (myocardium)

53. Heart Diseases/Disorders

54. Unstable angina may be a prelude to a heart attack chest pain that is sudden and gets increasingly worse occurs without cause (for example, it wakes you up from sleep) lasts longer than 15 - 20 minutes responds poorly to nitroglycerin may occur along with a drop in blood pressure or significant shortness of breath

55. Heart Diseases/Disorders Coronary artery balloon angioplasty

56. Heart Diseases/Disorders Aortic insufficiency heart valve disease in which the aortic valve weakens or balloons, preventing the valve from closing tightly leads to the backward flow of blood from the aorta into the left ventricle

57. Heart Diseases/Disorders Aortic stenosis aortic valve does not open fully, decreasing blood flow from the heart

58. Heart Diseases/Disorders Arrhythmias disorder of the heart rate (pulse) or heart rhythm, such as beating too fast (tachycardia), too slow (bradycardia), or irregularly Arrhythmia

59. Heart Diseases/Disorders Cardiomyopathy weakening of the heart muscle or a change in heart muscle structure often associated with inadequate heart pumping or other heart function problems Cardiomyopathy implantable-cardioverter defibrillator (ICD) may be needed to prevent sudden death

60. Heart Diseases/Disorders Cardiomyopathy - Causes Alcoholism and cocaine use Chemotherapy drugs Coronary artery disease End-stage kidney disease Genetic defects High blood pressure (hypertension) Infections due to viruses, HIV, Lyme disease, Chagas disease Nutritional deficiencies Pregnancy Systemic lupus erythematosus

61. Heart Diseases/Disorders Dilated cardiomyopathy condition in which the heart becomes weakened and enlarged, and it cannot pump blood efficiently decreased heart function can affect the lungs, liver, and other body systems

62. Heart Diseases/Disorders Hypertrophic cardiomyopathy condition in which the heart muscle becomes thick thickening makes it harder for blood to leave the heart, forcing the heart to work harder to pump blood

63. Heart Diseases/Disorders Hypertrophic cardiomyopathy – Causes often asymmetrical, meaning one part of the heart is thicker than the other parts condition is usually passed down through families believed to be a result of several defects with the genes that control heart muscle growth younger people are likely to have a more severe form of hypertrophic cardiomyopathy but the condition is seen in people of all ages

64. Heart Diseases/Disorders

65. Ischemic cardiomyopathy term that doctors use to describe patients who have reduced heart pumping (squeezing) due to coronary artery disease these patients often have congestive heart failure "Ischemic" means that an organ (such as the heart) is not getting enough blood and oxygen. "Cardio" means heart and "myopathy" means muscle-related disease.

66. Heart Diseases/Disorders Restrictive cardiomyopathy refers to a group of disorders in which the heart chambers are unable to properly fill with blood because of stiffness in the heart

67. Heart Diseases/Disorders Congenital heart disease refers to a problem with the heart's structure and function due to abnormal heart development before birth

68. Heart Diseases/Disorders Congenital heart disease – Causes most common type of birth defect responsible for more deaths in the first year of life than any other birth defects some heal over time, others will require treatment divided into two types: cyanotic and non- cyanotic

69. Heart Diseases/Disorders Cyanotic: Tetralogy of Fallot Transposition of the great vessels Tricuspid atresia Total anomalous pulmonary venous return Truncus arteriosus Hypoplastic left heart Pulmonary atresia Ebstein's anomaly

70. Heart Diseases/Disorders Non-cyanotic Ventricular septal defect (VSD) Atrial septal defect (ASD) Patent ductus arteriosus (PDA) Aortic stenosis Pulmonic stenosis Coarctation of the aorta Atrioventricular canal (endocardial cushion defect)

71. Heart Diseases/Disorders problems may occur alone or together majority of congenital heart diseases occur as an isolated defect but they can also be a part of various genetic and chromosomal syndromes Down syndrome trisomy 13 Turner syndrome Marfan syndrome Noonan syndrome DiGeorge syndrome.

72. Heart Diseases/Disorders Congestive Heart Failure condition in which the heart can't pump enough blood throughout the body - doesn’t mean that your heart has stopped or is about to stop working, just that your heart is not able to pump blood the way it should

73. Heart Diseases/Disorders Congestive Heart Failure The weakening of the heart's pumping ability causes: blood and fluid to back up into the lungs buildup of fluid in the feet, ankles and legs - edema tiredness, shortness of breath leading causes: coronary artery disease high blood pressure diabetes

74. Heart Diseases/Disorders Congestive Heart Failure Treatment: treat the underlying cause medicine heart transplantation (if other treatments fail) ~ 5 million people in the U.S. have heart failure contributes to 300,000 deaths each year

75. Heart Diseases/Disorders Coronary heart disease narrowing of the small blood vessels that supply blood and oxygen to the heart; also called coronary artery disease. Coronary Artery Disease

76. Heart Diseases/Disorders Causes of CHD usually caused by atherosclerosis - fatty material and other substances form a plaque build-up on artery walls, causing them to narrow blood flow to the heart can slow down or stop stable angina shortness of breath heart attack

77. Heart Diseases/Disorders Endocarditis inflammation of the inside lining of the heart chambers and heart valves risk factors injection drug use prior valve surgery recent dental surgery weakened valves bacterial/fungal infection

78. Heart Diseases/Disorders Heart attack (myocardial infarction) blood vessels that supply blood to the heart are blocked, preventing enough oxygen from getting to the heart heart muscle dies or becomes permanently damaged

79. Heart Diseases/Disorders Heart attack (myocardial infarction) most are caused by a blood clot that blocks one of the coronary arteries; if blood flow is blocked, heart starves for oxygen and heart cells die atherosclerosis: plaque (made up of cholesterol and other cells) builds up in the walls of your coronary arteries

80. Heart Diseases/Disorders Heart attack can occur as a result of the following: slow buildup of plaque may almost block one of your coronary arteries, preventing flow of oxygen-rich blood; more likely to happen when during exercise plaque itself develops cracks (fissures) or tears platelets stick, form a blood clot (thrombus) blood clot may completely block te passage of oxygen-rich blood to heart

81. Heart Diseases/Disorders Acute Myocardial Infarction

82. Heart Diseases/Disorders Progressive build-up of plaque in coronary artery

83. Heart Diseases/Disorders Heart attack symptoms Symptoms of a possible heart attack include chest pain and pain that radiates down the shoulder and arm. Some people (the elderly, people with diabetes, and women) may have little or no chest pain. Or, they may experience unusual symptoms (shortness of breath, fatigue, weakness). Women are more likely than men to have symptoms of nausea, vomiting, back or jaw pain, and shortness of breath with chest pain.

84. Heart Diseases/Disorders Heart attack symptoms

85. Heart Diseases/Disorders Atrial myxoma An atrial myxoma is a noncancerous tumor in the upper left or right side of the heart. It grows on the wall (atrial septum) that separates the two sides of the heart. Causes A myxoma is a primary heart (cardiac) tumor. This means that the tumor started within the heart. Most heart tumors start somewhere else

86. Heart Diseases/Disorders

87. Mitral regurgitation – acute mitral valve suddenly does not close properly, causing blood to flow backward (leak) into the upper heart chamber when the left lower heart chamber contracts Mitral regurgitation – chronic long-term disorder in which mitral valve does not close properly, causing blood to flow backward (leak) into the upper heart chamber when the left lower heart chamber contracts; progressive condition

88. Heart Diseases/Disorders Mitral stenosis mitral valve does not open fully, restricting blood flow

89. Heart Diseases/Disorders Mitral valve prolapse valve does not close properly Heart valve surgery - series

90. Heart Diseases/Disorders Pulmonary valve stenosis heart valve disorder that involves the pulmonary valve stenosis occurs when the valve cannot open wide enough, resulting in less blood flow to the lungs

91. Heart Diseases/Disorders Tricuspid regurgitation tricuspid valve does not close properly, causing blood to flow backward (leak) into the right atrium when the right ventricle contracts most common cause of tricuspid regurgitation is not damage to the valve itself but enlargement of the right ventricle, which may be a complication of any disorder that causes right ventricular failure

92. Heart Diseases/Disorders

93. The Heart: Cardiac Cycle Atria contract simultaneously Atria relax, then ventricles contract Systole = contraction Diastole = relaxation generally refers to ventricles

94. The Heart: Cardiac Cycle Atria contract simultaneously Atria relax, then ventricles contract Systole = contraction Diastole = relaxation

95. Filling Heart Chambers: Cardiac Cycle Figure 11.7, step 3 Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular systole (atria in diastole) Early diastole Isovolumetric contraction phase Ventricular ejection phase Isovolumetric relaxation Ventricular filling Left atrium Right atrium Left ventricle Right ventricle

96. The Heart: Cardiac Cycle Cardiac cycle—events of one complete heart beat Mid-to-late diastole—blood flows from atria into ventricles; SL closed, AV open Ventricular systole—blood pressure builds before ventricle contracts, pushing out blood; AV close, SL open Early diastole—atria finish refilling, ventricular pressure is low; SL valves snap shut, AV open

97. The Heart: Cardiac Cycle Heart Sounds “lub” – AV valves close 1 st sound; longer, louder “dub” – SL valves close 2 nd sound; shorter due to snapping shut Heart Murmur abnormal heart sounds often indicates valve problem but might be VSD, etc. valve doesn’t close tightly  lub-swish- dub

98. The Heart: Cardiac Output Cardiac output (CO) Amount of blood pumped by each side (ventricle) of the heart in one minute Stroke volume (SV) Volume of blood pumped by each ventricle in one contraction (each heartbeat) Usually remains relatively constant About 70 mL of blood is pumped out of the left ventricle with each heartbeat Heart rate (HR) Typically 75 beats per minute

99. The Heart: Cardiac Output CO = HR  SV CO = HR (75 beats/min)  SV (70 mL/beat) CO = 5250 mL/min Starling’s law of the heart—the more the cardiac muscle is stretched, the stronger the contraction Changing heart rate is the most common way to change cardiac output

100. The Heart: Regulation of Heart Rate Increased heart rate Sympathetic nervous system Crisis Low blood pressure Hormones Epinephrine Thyroxine Exercise Decreased blood volume

101. The Heart: Regulation of Heart Rate Decreased heart rate Parasympathetic nervous system High blood pressure or blood volume Decreased venous return

102. Cardiac Output Regulation Figure 11.8

103. Blood Vessels: The Vascular System Transport blood to the tissues and back Carry blood away from the heart Arteries Arterioles Exchanges between tissues and blood Capillary beds Return blood toward the heart Venules Veins

104. Blood Vessels: The Vascular System Figure 11.9a

105. Blood Vessels: Microscopic Anatomy Three layers (tunics) Tunic intima Endothelium Tunic media Smooth muscle Controlled by sympathetic nervous system Tunic externa Mostly fibrous connective tissue

106. Blood Vessels: The Vascular System Figure 11.9b

107. Differences Between Blood Vessels Walls of arteries are the thickest Lumens of veins are larger Larger veins have valves to prevent backflow Skeletal muscle “milks” blood in veins toward the heart Walls of capillaries are only one cell layer thick to allow for exchanges between blood and tissue

108. Blood Vessels: The Vascular System Figure 11.10

109. Movement of Blood Through Vessels Most arterial blood is pumped by the heart Veins use the milking action of muscles to help move blood

110. Capillary Beds Capillary beds consist of two types of vessels Vascular shunt—vessel directly connecting an arteriole to a venule True capillaries—exchange vessels Oxygen and nutrients cross to cells Carbon dioxide and metabolic waste products cross into blood

111. Capillary Beds Figure 11.11a

112. Capillary Beds Figure 11.11b

113. Major Arteries of System Circulation Aorta Largest artery in the body Leaves from the left ventricle of the heart Regions Ascending aorta—leaves the left ventricle Aortic arch—arches to the left Thoracic aorta—travels downward through the thorax Abdominal aorta—passes through the diaphragm into the abdominopelvic cavity

114. Major Arteries of System Circulation Arterial branches of the ascending aorta Right and left coronary arteries serve the heart

115. Blood Pressure measurement of force applied to the walls of the arteries as heart pumps blood through body determined by the force and amount of blood pumped size and flexibility of arteries continually changing depending on activity, temperature, diet, emotional state, posture, physical state, and medication use

116. Blood Pressure – How the Test is Performed usually measured while you are seated with your arm resting on a table, arm should be slightly bent so that it is at the same level as your heart, upper arm should be bare readings are measured in mmHg, given as two numbers (EX: 110/70) top #: systolic; maximum pressure exerted when heart contracts bottom #: diastolic; minimum pressure in arteries the heart is at rest Blood Pressure Video