1. Cardiovascular System Heart

2. Introduction of Cardiovascular Sytem Consists of; Consists of; 1. Blood 2. Heart 3. Blood Vessels

3. Location of Heart Heart lies between the lungs in the mediastinum. Heart lies between the lungs in the mediastinum.

5. Location of Heart Two-thirds of its mass is to the left of the midline Two-thirds of its mass is to the left of the midline

7. Location of Heart Precordium – The area of the chest anterior to the heart Precordium – The area of the chest anterior to the heart

8. Location of Heart Lies between the vertebral column and the sternum Lies between the vertebral column and the sternum

9. Structure and Function of Heart 1. Pericardium 2. Layers of the Heart Wall

10. Pericardium The heart is enclosed and held in place by the pericardium The heart is enclosed and held in place by the pericardium

11. Pericardium Consists of; Consists of; 1. Fibrous pericardium (outer) 2. Serous pericardium (inner)

13. Pericardium Fibrous pericardium – anchors the heart in the mediastinum Fibrous pericardium – anchors the heart in the mediastinum

15. Pericardium Serous pericardium composed of; Serous pericardium composed of; 1. Parietal layer 2. Visceral layer

17. Pericardium Pericardial cavity – a space between the parietal and visceral layers filled with pericardial fluid Pericardial cavity – a space between the parietal and visceral layers filled with pericardial fluid

19. Layer of the Heart 1. Epicardium 2. Myocardium 3. Endocardium

21. Epicardium Consists of the visceral layer of pericardium and connective tissue (adipose) Consists of the visceral layer of pericardium and connective tissue (adipose)

23. Myocardium Composed of cardiac muscle Composed of cardiac muscle

25. Myocardium The cells are branched, involuntary, and have one nucleus The cells are branched, involuntary, and have one nucleus

26. Myocardium The cells are connected by intercalated discs, which have gap junctions that allow ions to flow in between cells during depolarization The cells are connected by intercalated discs, which have gap junctions that allow ions to flow in between cells during depolarization

27. Endocardium Lines the chambers and covers the connective tissue in the heart valves Lines the chambers and covers the connective tissue in the heart valves

29. Endocardium It consists of endothelium It consists of endothelium

30. Chambers of the Heart 1. Right Atrium 2. Right Ventricle 3. Left Atrium 4. Left Ventricle

32. Chambers of the Heart On the surface of the heart are auricles and sulci On the surface of the heart are auricles and sulci

33. Chambers of the Heart Auricles – small pouches on the anterior surface of each atrium Auricles – small pouches on the anterior surface of each atrium

35. Chambers of the Heart Sulci – Are grooves that contain coronary arteries and fat and separate the chambers Sulci – Are grooves that contain coronary arteries and fat and separate the chambers

37. Right Atrium The right atrium receives systemic venous blood from; The right atrium receives systemic venous blood from; 1. Superior Vena Cava 2. Inferior Vena Cava 3. Coronary sinus

39. Right Atrium The atrium receives blood low in O2 and high in CO2 The atrium receives blood low in O2 and high in CO2

40. Right Atrium Interatrial septum - separates the right and left atria Interatrial septum - separates the right and left atria

41. Right Atrium Fossa ovalis – an oval depression in the interatrial septum; it is a remnant of the foramen ovale Fossa ovalis – an oval depression in the interatrial septum; it is a remnant of the foramen ovale

42. Right Atrium Tricuspid Valve – Blood passes from the right atrium into the right ventricle through here Tricuspid Valve – Blood passes from the right atrium into the right ventricle through here

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

46. Right Ventricle Pulmonary semilunar valve - Blood passes from the right ventricle to the pulmonary trunk via this valve Pulmonary semilunar valve - Blood passes from the right ventricle to the pulmonary trunk via this valve

48. Left Atrium Receives pulmonary venous blood from the pulmonary veins which is rich in oxygen and low in CO2 Receives pulmonary venous blood from the pulmonary veins which is rich in oxygen and low in CO2

50. Left Atrium Mitral Valve – Blood passes from the left atrium to the left ventricle via this valve Mitral Valve – Blood passes from the left atrium to the left ventricle via this valve

52. Left Ventricle Thickest and strongest chamber Thickest and strongest chamber

54. Left Ventricle Forms the apex of the heart Forms the apex of the heart

56. Left Ventricle Blood passes from the left ventricle through the aortic valve into the aorta Blood passes from the left ventricle through the aortic valve into the aorta

58. Left Ventricle During fetal life the ductus arteriosus shunts blood from the pulmonary trunk into the aorta During fetal life the ductus arteriosus shunts blood from the pulmonary trunk into the aorta

59. Left Ventricle At birth the ductus arteriosus closes and becomes the ligamentum arteriosum At birth the ductus arteriosus closes and becomes the ligamentum arteriosum

61. Left Ventricle The left ventricle is separted from the right ventricle by the interventricular septum The left ventricle is separted from the right ventricle by the interventricular septum

62. Myocardial Thickness and Function The atria walls are thin because they only pump blood to the nearby ventricles The atria walls are thin because they only pump blood to the nearby ventricles

63. Myocardial Thickness and Function The ventricle wall are thicker because they pump blood greater distances The ventricle wall are thicker because they pump blood greater distances

64. Myocardial Thickness and Function The right ventricle walls are thinner than the left because they pump blood to the nearby lungs The right ventricle walls are thinner than the left because they pump blood to the nearby lungs

66. Myocardial Thickness and Function The left ventricle walls are thicker because they pump blood through the body The left ventricle walls are thicker because they pump blood through the body

68. Function of Heart Valves Valves open and close in response to pressure changes as the heart contracts and relaxes Valves open and close in response to pressure changes as the heart contracts and relaxes

69. Myocardial Thickness and Function Two types of valves; Two types of valves; 1. Atrioventricular Valves 2. Semilunar

70. Atrioventricular Valves 1. Tricuspid (right side) 2. Mitral or bicuspid (left side)

72. Atrioventricular Valves AV valves prevent blood flow from the ventricles back into the atria AV valves prevent blood flow from the ventricles back into the atria

73. Atrioventricular Valves Back flow is prevented by the contraction of papillary muscles and tightening the chordae tendinae Back flow is prevented by the contraction of papillary muscles and tightening the chordae tendinae

75. Semilunar Valves SL valves allow ejection of blood from the heart into the pulmonary arteries and aorta SL valves allow ejection of blood from the heart into the pulmonary arteries and aorta

76. Semilunar Valves Prevent back flow into the ventricles Prevent back flow into the ventricles

77. Circulation of Blood 1. Systemic 2. Pulmonary 3. Coronary

78. Systemic Circulation The left side of the heart pumps oxygenated blood from the left ventricle into the ascending aorta. The left side of the heart pumps oxygenated blood from the left ventricle into the ascending aorta.

80. Systemic Circulation The coronary arteries arise off of the ascending aorta The coronary arteries arise off of the ascending aorta

81. Pulmonary Circulation The right side of the heart receives deoxygenated blood from the body. The right side of the heart receives deoxygenated blood from the body.

83. Pulmonary Circulation The right side of the heart pumps blood from the right ventricle and sends it into the lungs via the pulmonary artery The right side of the heart pumps blood from the right ventricle and sends it into the lungs via the pulmonary artery

85. Circulation of Blood Right atrium receives blood from the superior and inferior vena cava Right atrium receives blood from the superior and inferior vena cava

86. Circulation of Blood The Left atrium receives blood from the pulmonary veins The Left atrium receives blood from the pulmonary veins

87. Coronary Circulation It delivers oxygenated blood and nutrients to and removes CO2 and wastes from the myocardium It delivers oxygenated blood and nutrients to and removes CO2 and wastes from the myocardium

88. Coronary Circulation The left and right coronary arteries branch from the ascending aorta and carry oxygenated blood The left and right coronary arteries branch from the ascending aorta and carry oxygenated blood

90. Coronary Circulation Left coronary artery branches into the; Left coronary artery branches into the; 1. Left anterior descending artery 2. Circumflex artery

92. Coronary Circulation Right coronary artery branches into; Right coronary artery branches into; 1. Marginal artery 2. Posterior descending artery

94. Coronary Circulation Deoxygenated blood returns to the right atrium through the coronary sinus Deoxygenated blood returns to the right atrium through the coronary sinus

96. Histology of Cardiac Muscle In comparison to skeletal muscle fibers, cardiac muscle fibers are involuntary, shorter in length, larger in diameter, and squarish rather than circular in transverse section. In comparison to skeletal muscle fibers, cardiac muscle fibers are involuntary, shorter in length, larger in diameter, and squarish rather than circular in transverse section.

97. Histology of Cardiac Muscle They also exhibit branching They also exhibit branching

98. Histology of Cardiac Muscle Have same arrangement of actin and myosin, and the same bands, zones, and Z discs as skeletal muscles Have same arrangement of actin and myosin, and the same bands, zones, and Z discs as skeletal muscles

99. Cardiac Conduction System There is an atrial and ventricular network There is an atrial and ventricular network

100. Cardiac Conduction System Fibers within the networks are connected by intercalated discs Fibers within the networks are connected by intercalated discs

101. Cardiac Conduction System The intercalated discs allow the fibers to work together so that each network serves as a functional unit The intercalated discs allow the fibers to work together so that each network serves as a functional unit

102. Cardiac Conduction System Cardiac muscle cells are autorhythmic cells because they are self-excitable. Cardiac muscle cells are autorhythmic cells because they are self-excitable.

103. Cardiac Conduction System They repeatedly generate spontaneous action potentials that then trigger heart contraction They repeatedly generate spontaneous action potentials that then trigger heart contraction

104. Cardiac Conduction System The components of this system are; The components of this system are; 1. Sinoatrial node (SA) 2. Atrioventricular node (AV) 3. Bundle of His 4. Right and Left Bundle branches 5. Purkinje fibers

106. Cardiac Conduction System SA node is the pacemaker SA node is the pacemaker

108. Cardiac Conduction System From the SA node, a cardiac action potential travels throughout the atrial muscle and down to the AV node From the SA node, a cardiac action potential travels throughout the atrial muscle and down to the AV node

110. Cardiac Conduction System At the AV node the impulse is delayed (about 0.1sec) At the AV node the impulse is delayed (about 0.1sec)

112. Cardiac Conduction System This gives the atria time to completely contract before ventricular contraction begins This gives the atria time to completely contract before ventricular contraction begins

114. Cardiac Conduction System It then passes through the Bundle of His, Right and Left Bundle Branches, and the Purkinje fibers, resulting in ventricular contraction It then passes through the Bundle of His, Right and Left Bundle Branches, and the Purkinje fibers, resulting in ventricular contraction

116. Cardiac Cycle Consists of; Consists of; 1. Systole (contraction) and Diastole (relaxation) of both atria 2. Systole and Diastole of both ventricles

117. Atrial Diastole The atria are relaxed The atria are relaxed

118. Atrial Diastole They receive blood from three veins They receive blood from three veins

119. Atrial Diastole The A-V valves are open, allowing for 70% of ventricular filling. The ventricles are therefore also in diastole. The A-V valves are open, allowing for 70% of ventricular filling. The ventricles are therefore also in diastole.

120. Atrial Systole The SA node then fires; after this electrical event, atrial systole begins (a mechanical event) The SA node then fires; after this electrical event, atrial systole begins (a mechanical event)

121. Atrial Systole Atrial contraction accounts for 30% of ventricular filling Atrial contraction accounts for 30% of ventricular filling

122. Ventricular Systole Shortly after the beginning of ventricular depolarization, ventricular systole begins Shortly after the beginning of ventricular depolarization, ventricular systole begins

123. Ventricular Systole The ventricles contract. The ventricular pressure becomes higher than atrial pressures, causing the AV valves to close. The ventricles contract. The ventricular pressure becomes higher than atrial pressures, causing the AV valves to close.

124. Ventricular Systole The SL valves open when the ventricular pressure becomes higher than aortic (pulmonary arterial) pressure. The SL valves open when the ventricular pressure becomes higher than aortic (pulmonary arterial) pressure.

125. Ventricular Systole Then blood is ejected into the aorta and pulmonary trunk. Then blood is ejected into the aorta and pulmonary trunk.

126. Ventricular Diastole Begins when the ventricles relax Begins when the ventricles relax

127. Ventricular Diastole Ventricular pressures drop below arterial pressures, causing the SL valves to close Ventricular pressures drop below arterial pressures, causing the SL valves to close

128. Ventricular Diastole The ventricular pressures continue to drop below atrial pressures, causing the AV valves to open The ventricular pressures continue to drop below atrial pressures, causing the AV valves to open

129. Auscultation Listening to sounds within the body with a stethoscope Listening to sounds within the body with a stethoscope

130. Auscultation The first heart sound (lubb) is created by the closing of the AV valves soon after ventricular systole begins The first heart sound (lubb) is created by the closing of the AV valves soon after ventricular systole begins

131. Auscultation The second heart sound (dupp) represents the closing of the SL valves close to the end of the ventricular systole. The second heart sound (dupp) represents the closing of the SL valves close to the end of the ventricular systole.

132. Cardiac Output The volume of blood ejected from the left ventricle (or the right ventricle) into the aorta (or pulmonary trunk) each minute. The volume of blood ejected from the left ventricle (or the right ventricle) into the aorta (or pulmonary trunk) each minute.

133. Cardiac Output Cardiac Output = Stroke volume X Heart Rate Cardiac Output = Stroke volume X Heart Rate

134. Cardiac Output Stroke volume – the volume of blood ejected by the ventricle with each contraction Stroke volume – the volume of blood ejected by the ventricle with each contraction

135. Cardiac Output Stroke Volume = End Diastolic Volume (130ml) – End Systolic Volume (60ml) Stroke Volume = End Diastolic Volume (130ml) – End Systolic Volume (60ml)

136. Cardiac Output Heart Rate – number of beats per minute Heart Rate – number of beats per minute

137. Regulation of Heart Rate Sympathetics impulses increase heart rate and force of contraction Sympathetics impulses increase heart rate and force of contraction

138. Regulation of Heart Rate Parasympathetic impulses decrease heart rate Parasympathetic impulses decrease heart rate

139. Tachycardia Heart Rate over 100 beats/min Heart Rate over 100 beats/min

140. Bradycardia Heart Rate below 60 beats/min Heart Rate below 60 beats/min

141. Fibrillation Prolonged tachycardia Prolonged tachycardia

142. Exercise And The Heart Sustained exercise increases oxygen demand in muscles Sustained exercise increases oxygen demand in muscles

143. Exercise And The Heart Resting cardiac output 5.25 Liters/minute Resting cardiac output 5.25 Liters/minute

144. Exercise And The Heart In sedentary people CO may go up to 22 liters/minute In sedentary people CO may go up to 22 liters/minute

145. Exercise And The Heart In trained athletes CO may go up to 40 liters/minute In trained athletes CO may go up to 40 liters/minute

146. Exercise And The Heart Sedentary people increase their CO during exercise by an increase in HR and SV Sedentary people increase their CO during exercise by an increase in HR and SV

147. Exercise And The Heart Sedentary people Sedentary people Increase in HR more dramatic Increase in HR more dramatic Stroke volume only goes up by 10-35% Stroke volume only goes up by 10-35%

148. Exercise And The Heart For a given activity, sedentary people’s maximum HR will be higher than in a trained athlete For a given activity, sedentary people’s maximum HR will be higher than in a trained athlete

149. Exercise And The Heart Trained athletes increase their CO during exercise by an increase in HR and SV Trained athletes increase their CO during exercise by an increase in HR and SV

150. Exercise And The Heart Trained Athletes Trained Athletes Increase in SV more dramatic than HR Increase in SV more dramatic than HR Their SV goes up to 60% Their SV goes up to 60%

151. Exercise And The Heart Athletes have larger stroke volumes due to longer filling time Athletes have larger stroke volumes due to longer filling time

152. Electrocardiogram (ECG or EKG) Records the electrical currents of the body generated by the heart Records the electrical currents of the body generated by the heart

153. Electrocardiogram (ECG or EKG) P= depolarization of the atria P= depolarization of the atria

155. Electrocardiogram (ECG or EKG) QRS= depolarization of the ventricles QRS= depolarization of the ventricles (repolarization of atria, but don’t see)

157. Electrocardiogram (ECG or EKG) T= ventricles repolarization T= ventricles repolarization

159. Electrocardiogram (ECG or EKG) PR interval= between beginning of atrial depolarization and ventrical depolarization PR interval= between beginning of atrial depolarization and ventrical depolarization

161. Electrocardiogram (ECG or EKG) ST segment= ventricle contraction ST segment= ventricle contraction

163. Electrocardiogram (ECG or EKG) QT interval = ventricle depolarization through ventricle repolarization QT interval = ventricle depolarization through ventricle repolarization