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The Heart
Chambers of the Heart
Cardiac Cycle Ventricular systole -  isovolumic contraction -  ejection Ventricular diastole -  isovolumic relaxation -  r...
4) Ventricular Filling 5) Atrial Contraction <ul><li>Isovolumic  </li></ul><ul><li>Ventricular Contraction </li></ul>2) Ve...
Can the heart beat by itself ?
 
Autorhythm The heart can beat on its own without the need for exogenous commands.
Skeletal muscle Motor nerve Conclusion ? The heart generates electricity.
 
<ul><li>TERMINOLOGY </li></ul><ul><li>Excitation </li></ul><ul><li>-  definition: generation of  action potentials </li></...
Excitation -Contraction  coupling Excitation Contraction [  Ca ++  ] i (Action Potentials) (shortening)
Sinus-Atrial node (SA node) Atria Atrial-ventricular node (AV node) Ventricles Sequence of excitation
SA node - located in the right atrial wall, just inferior to the entrance of the superior vena cava.  Original Impulses fr...
Conduction of  Electrical Impulses in the Heart
 
  Conduction of Action Potentials from Cell to Cell <ul><ul><li>through gap junctions in intercalated discs  </li></ul></u...
Conduction in Atria The electrical impulses from SA node spread through the entire right and left atrial muscle mass, trig...
Delay at A-V Node - The impulses from S-A node travel to  atrioventricular (A-V) node . -  A-V node is located in lower en...
Delay at A-V Node -  A-V node is the only normal route that impulses from SA node are transmitted into ventricles. -  Cond...
<ul><li>From AV node to Ventricles </li></ul><ul><li>His bundle </li></ul><ul><ul><li>left branch (anterior/posterior divi...
<ul><li>1) Purkinje fibers </li></ul><ul><ul><li>located in the subendocardial layer </li></ul></ul><ul><ul><li>- fastest ...
Rapid conduction in the ventricles simultaneous  excitation of the ventricles functional syncytium
NNote :  -  Each electrical impulse can trigger cardiac muscle contraction normally only once.  -  A normal heart generate...
Excitation Contraction [  Ca ++  ] i (Action Potentials) (shortening) Properties of Cardiac Muscle Excitation of the heart...
Properties of Cardiac Muscle -  Myocytes depend heavily on oxygen and blood supply.  -  Not fatigue -  Excitability Cycle ...
RRole of a Long Refractory Period – 1 prevent ventricles from contracting at too high rates so that enough time is allowed...
Role of Long refractory period - 2 Prevent retrograde excitation
ELECTROCARDIOGRAPHY   (ECG)
EELECTROCARDIOGRAPHY   ((ECG) the recording of electrical activities of the heart via electrodes placed on body surface.
<ul><ul><ul><li>Applications of ECG </li></ul></ul></ul><ul><ul><ul><ul><ul><li>1)   measure automaticity </li></ul></ul><...
Waves and Intervals of ECG P wave :  atrial depolarization QRS complex :  ventricular depolarization T wave : ventricular ...
PR Interval
Disorders of the Cardiac Conduction System ----  Arrhythmias -  refers to abnormal initiation or conduction of electrical ...
<ul><ul><li>Bradycardia  </li></ul></ul><ul><li>slow heart rate ( < 60 beats/min) </li></ul><ul><li>  </li></ul><ul><ul><l...
- contract uncoordinatedly and extremely rapidly. - Ventricular fibrillation is lethal. Atrial or Ventricular   Flutter  a...
is when the heart beat is triggered by ectopic pacemakers (cells other than SA node).   Premature contraction
Conduction Block
Artificial Pacemaker Application:  sinus abnormality, complete AV or ventricular block Function: - generate electric pulse...
Heart Sounds Four heart sounds can be recorded via phonocardiography, but normally only two, the  first  and the  second  ...
<ul><li>First heart sound :  </li></ul><ul><li>occurs when the  atrioventricular (AV) valves close   at the beginning of v...
- occurs when  aortic  and  pulmonary semilunar valves close  at the beginning of ventricular dilation - generated by the ...
Heart Murmur - abnormal heart sound  - occur in valvular diseases and septal defects
Two Basic Types of Valvular Diseases  1)  valvular stenosis , a narrowing of the valve 2)  valvular insufficiency  (incomp...
MECHANICAL PROPERTIES OF THE HEART <ul><li>CONTENT </li></ul><ul><ul><ul><li>Heart Rate </li></ul></ul></ul><ul><ul><ul><l...
  Heart Rate   the number of heart beats in 1 minute.  Normal value: 60-100/min Stroke volume the volume of blood pumped o...
Cardiac Output (CO)   the amount of blood pumped out by each ventricle in 1 minute.  Cardiac output = stroke volume x hear...
Ejection Fraction   = stroke volume   end-diastolic ventricular volume 70 ml    130 ml  =  54% 60 ml End of diastole 130...
End of diastole 133 ml 120 ml End of systole SV = Ejection Fraction   120 ml    133 ml  =  90% increases  during exercise
<ul><li>Preload   </li></ul><ul><ul><ul><li>the force that stretches the muscle before contraction.   </li></ul></ul></ul>...
Preload  to ventricles =  ventricular  end diastolic pressure - the degree of stretch of the ventricular muscle cells just...
Afterload  to left ventricle:  aortic arterial pressure Afterload  to right ventricle:  pulmonary arterial pressure Afterl...
Contractility   - the intrinsic strength of cardiac muscles.
<ul><li>Factors on Cardiac Output   </li></ul><ul><li>  </li></ul><ul><li>Preload :  </li></ul><ul><li>  </li></ul><ul><li...
<ul><li>Factors on Cardiac Output   </li></ul><ul><li>  </li></ul><ul><li>Preload :  </li></ul><ul><li>  </li></ul>   Pre...
More in More out <ul><li>Factors on Cardiac Output   </li></ul><ul><li>  </li></ul><ul><li>Preload :  </li></ul><ul><li>  ...
<ul><li>Factors on Cardiac Output   </li></ul><ul><li>  </li></ul><ul><li>Preload :   </li></ul><ul><li>  </li></ul><ul><l...
<ul><li>Factors on Cardiac Output   </li></ul><ul><li>  </li></ul><ul><li>Preload :  </li></ul><ul><li>  </li></ul><ul><li...
<ul><li>Factors on Cardiac Output   </li></ul><ul><li>  </li></ul><ul><li>Preload :  </li></ul><ul><li>  </li></ul><ul><li...
less in less out <ul><li>Factors on Cardiac Output   </li></ul><ul><li>  </li></ul><ul><li>Preload :  </li></ul><ul><li>  ...
REGULATION OF THE HEART FUNCTION
Regulation of the Cardiac Function   <ul><li>1)  Nervous control   </li></ul><ul><ul><li>Sympathetic control </li></ul></u...
Regulation of the Cardiac Function   <ul><li>1)  Nervous control   </li></ul><ul><ul><li>Sympathetic control </li></ul></u...
<ul><li>Sympathetic Nervous System </li></ul><ul><ul><li>-   controls all components of the heart. </li></ul></ul><ul><ul>...
Cell m <ul><li>Parasympathetic Nervous System (PNS) </li></ul><ul><ul><li>-  controls SA node and AV node. </li></ul></ul>...
<ul><ul><li>Higher Centers of Autonomic Nervous System </li></ul></ul><ul><ul><ul><li>-  Medulla Oblongata </li></ul></ul>...
Centers in Medulla Oblongata Sympathetic center:  distinct  accelerator  and  augmentor Parasympathetic center:  Nucleus v...
Hypothalamus, Thalamus, Cerebral cortex Involved in the cardiac response to environmental  temperature  changes,  exercise...
Neural Control via Reflexes
Baroreceptors
1) Baroreceptor Reflex -  stimulated by increase in arterial pressure (stretch) -  Effect:  negative chronotropic and inot...
2) Chemoreceptor Reflex
Chemoreceptors Chemoreceptors Chemoreceptors
2)   Chemoreceptor Reflex -  stimulated by   oxygen ,   pH ,  or   CO 2 -  overall effect: positive choronotropic and i...
3)  Proprioceptor Reflex -  Stimulated by muscle and joint movement -  Effects: increase heart rate during exercise
Regulation by Hormones <ul><li>Epinephrine   </li></ul><ul><ul><li>-  released from adrenal gland. </li></ul></ul><ul><ul>...
Autoregulation of the Heart Stroke volume is autoregulated by ventricular filling ( Frank-Starling law ).   SV More in Mor...
<ul><li>4) Other Factors </li></ul><ul><li>-  Blood level of ionic calcium, sodium, and potassium </li></ul><ul><li>Hyperc...
Blood Supply to Cardiac Muscles
Can cardiac muscles get nutrients from the blood in heart chambers?
The cardiac muscles get nutrients from coronary circulation. Anterior view Posterior view
Coronary arterial anastomosis
Coronary venous blood is emptied into the right atrium through cardiac veins and coronary sinus. coronary sinus Posterior ...
Blockade of coronary artery causes  myocardial infarction , or  heart attack .
Coronary Atherosclerosis
dull white and slightly elevated fibrous plaque ( atheroma ) on coronary arterial lumen.   Typical lesion of Coronary Athe...
 composed of lipid, smooth muscle, macrophages, and connective tissues.  cause stenosis of coronary arteries Histology o...
   occur often at arterial branching points
Surgical Therapies 1)
2)  Coronary angioplasty
3)  Stenting
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A heart physiology

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A heart physiology

  1. 1. The Heart
  2. 2. Chambers of the Heart
  3. 3. Cardiac Cycle Ventricular systole - isovolumic contraction - ejection Ventricular diastole - isovolumic relaxation - rapid filling - atrial contraction
  4. 4. 4) Ventricular Filling 5) Atrial Contraction <ul><li>Isovolumic </li></ul><ul><li>Ventricular Contraction </li></ul>2) Ventricular Ejection 3) Isovolumic Ventricular Relaxation
  5. 5. Can the heart beat by itself ?
  6. 7. Autorhythm The heart can beat on its own without the need for exogenous commands.
  7. 8. Skeletal muscle Motor nerve Conclusion ? The heart generates electricity.
  8. 10. <ul><li>TERMINOLOGY </li></ul><ul><li>Excitation </li></ul><ul><li>- definition: generation of action potentials </li></ul><ul><li>- different from contraction </li></ul><ul><li>Contraction </li></ul><ul><ul><li>- definition: shortening of muscle cells </li></ul></ul><ul><ul><li>- triggered by excitation </li></ul></ul>
  9. 11. Excitation -Contraction coupling Excitation Contraction [ Ca ++ ] i (Action Potentials) (shortening)
  10. 12. Sinus-Atrial node (SA node) Atria Atrial-ventricular node (AV node) Ventricles Sequence of excitation
  11. 13. SA node - located in the right atrial wall, just inferior to the entrance of the superior vena cava. Original Impulses from S-A Node The electrical impulses are normally generated by a group of specialized pacemaker cells at sinoatrial (SA) node.
  12. 14. Conduction of Electrical Impulses in the Heart
  13. 16.   Conduction of Action Potentials from Cell to Cell <ul><ul><li>through gap junctions in intercalated discs </li></ul></ul><ul><ul><li>(electrical synapses) </li></ul></ul>
  14. 17. Conduction in Atria The electrical impulses from SA node spread through the entire right and left atrial muscle mass, triggering contraction of the right and left atrium.
  15. 18. Delay at A-V Node - The impulses from S-A node travel to atrioventricular (A-V) node . - A-V node is located in lower end of the interatrial septum near the tricuspid valve. A-V node
  16. 19. Delay at A-V Node - A-V node is the only normal route that impulses from SA node are transmitted into ventricles. - Conduction speed in A-V node is slow (delay). - This delay allows time for the atria to finish contraction and empty their contents into the ventricles before ventricles start to contract.
  17. 20. <ul><li>From AV node to Ventricles </li></ul><ul><li>His bundle </li></ul><ul><ul><li>left branch (anterior/posterior division) </li></ul></ul><ul><ul><li>- right branch </li></ul></ul>His bundle
  18. 21. <ul><li>1) Purkinje fibers </li></ul><ul><ul><li>located in the subendocardial layer </li></ul></ul><ul><ul><li>- fastest conduction (4 m/s) </li></ul></ul><ul><li>2) Ordinary ventricular myocardial cells </li></ul><ul><ul><li>able to conduct AP at a slower speed </li></ul></ul>After the delay at A-V node, the impulses rapidly spread to the ventricles via specialized fibers, Purkinje fibers . Rapid Conduction in Ventricles
  19. 22. Rapid conduction in the ventricles simultaneous excitation of the ventricles functional syncytium
  20. 23. NNote : - Each electrical impulse can trigger cardiac muscle contraction normally only once. - A normal heart generates 60 to 100 impulses in 1 minute at resting state. 1 1
  21. 24. Excitation Contraction [ Ca ++ ] i (Action Potentials) (shortening) Properties of Cardiac Muscle Excitation of the heart is triggered by electrical impulse rather than neural transmitters. Contraction of the heart is triggered by elevation of intracellular calcium influx.
  22. 25. Properties of Cardiac Muscle - Myocytes depend heavily on oxygen and blood supply. - Not fatigue - Excitability Cycle The myocytes have Long refractory period during which they do not respond to any electrical impulses.
  23. 26. RRole of a Long Refractory Period – 1 prevent ventricles from contracting at too high rates so that enough time is allowed for refill of the ventricles
  24. 27. Role of Long refractory period - 2 Prevent retrograde excitation
  25. 28. ELECTROCARDIOGRAPHY (ECG)
  26. 29. EELECTROCARDIOGRAPHY ((ECG) the recording of electrical activities of the heart via electrodes placed on body surface.
  27. 30. <ul><ul><ul><li>Applications of ECG </li></ul></ul></ul><ul><ul><ul><ul><ul><li>1)   measure automaticity </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>HR, rhythmicity, pacemaker </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>2)   measure conductivity </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>pathway, reentry, block </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>3)   reveal hypertrophy </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>4)   reveal ischemic damages </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>location, size, and progress </li></ul></ul></ul></ul></ul>
  28. 31. Waves and Intervals of ECG P wave : atrial depolarization QRS complex : ventricular depolarization T wave : ventricular repolarization
  29. 32. PR Interval
  30. 33. Disorders of the Cardiac Conduction System ---- Arrhythmias - refers to abnormal initiation or conduction of electrical impulses in the heart. - caused by ischemia, fibrosis, inflammation, or drugs.
  31. 34. <ul><ul><li>Bradycardia </li></ul></ul><ul><li>slow heart rate ( < 60 beats/min) </li></ul><ul><li>  </li></ul><ul><ul><li>Tachycardia </li></ul></ul><ul><li>fast heart rate ( > 100 beats/min) </li></ul>
  32. 35. - contract uncoordinatedly and extremely rapidly. - Ventricular fibrillation is lethal. Atrial or Ventricular Flutter and Fibrillation
  33. 36. is when the heart beat is triggered by ectopic pacemakers (cells other than SA node). Premature contraction
  34. 37. Conduction Block
  35. 38. Artificial Pacemaker Application: sinus abnormality, complete AV or ventricular block Function: - generate electric pulses - sensing - antitachyarrhythmia
  36. 39. Heart Sounds Four heart sounds can be recorded via phonocardiography, but normally only two, the first and the second heart sounds, are audible through a stethoscope.
  37. 40. <ul><li>First heart sound : </li></ul><ul><li>occurs when the atrioventricular (AV) valves close at the beginning of ventricular contraction. </li></ul><ul><li>generated by the vibration of the blood and the ventricular wall </li></ul><ul><li>is louder, longer, more resonant than the second heart sound. </li></ul>
  38. 41. - occurs when aortic and pulmonary semilunar valves close at the beginning of ventricular dilation - generated by the vibration of the blood and the aorta - Aortic valve closes slightly before pulmonary valve. Second heart sound
  39. 42. Heart Murmur - abnormal heart sound - occur in valvular diseases and septal defects
  40. 43. Two Basic Types of Valvular Diseases 1) valvular stenosis , a narrowing of the valve 2) valvular insufficiency (incompetence). A valve is unable to close fully; so there is some backflow (regurgitation) of blood.
  41. 44. MECHANICAL PROPERTIES OF THE HEART <ul><li>CONTENT </li></ul><ul><ul><ul><li>Heart Rate </li></ul></ul></ul><ul><ul><ul><li>Stroke volume </li></ul></ul></ul><ul><ul><ul><li>Cardiac Output (CO) </li></ul></ul></ul><ul><ul><ul><li>Ejection Fraction </li></ul></ul></ul><ul><ul><ul><li>Preload </li></ul></ul></ul><ul><ul><ul><li>Afterload </li></ul></ul></ul><ul><ul><ul><li>Contractility </li></ul></ul></ul><ul><ul><ul><li>Frank-Starling Mechanism </li></ul></ul></ul><ul><ul><ul><li>Factors on Cardiac Output </li></ul></ul></ul>
  42. 45.   Heart Rate the number of heart beats in 1 minute. Normal value: 60-100/min Stroke volume the volume of blood pumped out by each ventricle per each contraction. SV
  43. 46. Cardiac Output (CO) the amount of blood pumped out by each ventricle in 1 minute. Cardiac output = stroke volume x heart rate Example: 70 ml x 75 beat/min = 5,250 ml/min 70 75 beat/min ml
  44. 47. Ejection Fraction = stroke volume  end-diastolic ventricular volume 70 ml  130 ml = 54% 60 ml End of diastole 130 ml 70 ml End of systole SV =
  45. 48. End of diastole 133 ml 120 ml End of systole SV = Ejection Fraction 120 ml  133 ml = 90% increases during exercise
  46. 49. <ul><li>Preload </li></ul><ul><ul><ul><li>the force that stretches the muscle before contraction. </li></ul></ul></ul><ul><li>Afterload </li></ul><ul><ul><ul><li>the force that stretches muscle during contraction. </li></ul></ul></ul>preload afterload
  47. 50. Preload to ventricles = ventricular end diastolic pressure - the degree of stretch of the ventricular muscle cells just before they contract. - determined by ventricular filling.
  48. 51. Afterload to left ventricle: aortic arterial pressure Afterload to right ventricle: pulmonary arterial pressure Afterload to the left ventricle is greater than that to the right ventricle. Aortic arterial pressure
  49. 52. Contractility - the intrinsic strength of cardiac muscles.
  50. 53. <ul><li>Factors on Cardiac Output </li></ul><ul><li>  </li></ul><ul><li>Preload : </li></ul><ul><li>  </li></ul><ul><li>2) Afterload :   </li></ul><ul><li>3) Contractility : </li></ul><ul><li>  </li></ul><ul><li>4) Heart Rate : </li></ul>
  51. 54. <ul><li>Factors on Cardiac Output </li></ul><ul><li>  </li></ul><ul><li>Preload : </li></ul><ul><li>  </li></ul> Preload   cardiac output (Starling-Frank Mechanism)
  52. 55. More in More out <ul><li>Factors on Cardiac Output </li></ul><ul><li>  </li></ul><ul><li>Preload : </li></ul><ul><li>  </li></ul> Preload   cardiac output (Starling-Frank Mechanism)
  53. 56. <ul><li>Factors on Cardiac Output </li></ul><ul><li>  </li></ul><ul><li>Preload : </li></ul><ul><li>  </li></ul><ul><li>2) Afterload :   </li></ul> afterload   CO R
  54. 57. <ul><li>Factors on Cardiac Output </li></ul><ul><li>  </li></ul><ul><li>Preload : </li></ul><ul><li>  </li></ul><ul><li>2) Afterload :   </li></ul><ul><li>3) Contractility : </li></ul> contractility   CO
  55. 58. <ul><li>Factors on Cardiac Output </li></ul><ul><li>  </li></ul><ul><li>Preload : </li></ul><ul><li>  </li></ul><ul><li>2) Afterload :   </li></ul><ul><li>3) Contractility : </li></ul><ul><li>  </li></ul><ul><li>4) Heart Rate : </li></ul>dual effects  CO =  Heart Rate x Stroke Volume
  56. 59. less in less out <ul><li>Factors on Cardiac Output </li></ul><ul><li>  </li></ul><ul><li>Preload : </li></ul><ul><li>  </li></ul><ul><li>2) Afterload :   </li></ul><ul><li>3) Contractility : </li></ul><ul><li>  </li></ul><ul><li>4) Heart Rate : </li></ul>dual effects Heart Rate Stoke Volume  CO =  Heart Rate x  Stroke Volume 300% 400%
  57. 60. REGULATION OF THE HEART FUNCTION
  58. 61. Regulation of the Cardiac Function <ul><li>1) Nervous control </li></ul><ul><ul><li>Sympathetic control </li></ul></ul><ul><ul><li>Parasympathetic control </li></ul></ul><ul><ul><li>Higher centers </li></ul></ul><ul><ul><li>Reflexes </li></ul></ul><ul><li>2) Hormonal Control </li></ul><ul><li>3) Autoregulation </li></ul><ul><li>4) Other factors </li></ul>
  59. 62. Regulation of the Cardiac Function <ul><li>1) Nervous control </li></ul><ul><ul><li>Sympathetic control </li></ul></ul><ul><ul><li>Parasympathetic control </li></ul></ul>
  60. 63. <ul><li>Sympathetic Nervous System </li></ul><ul><ul><li>- controls all components of the heart. </li></ul></ul><ul><ul><li>- release Norepinephrine (NE). </li></ul></ul><ul><ul><li>- increases heart rate (positive chronotropic) and contractility (positive inotropic) . </li></ul></ul>Cell  1
  61. 64. Cell m <ul><li>Parasympathetic Nervous System (PNS) </li></ul><ul><ul><li>- controls SA node and AV node. </li></ul></ul><ul><ul><li>releases Acetylcholine (Ach). </li></ul></ul><ul><ul><li>- decreases heart rate (negative chronotropic). </li></ul></ul><ul><ul><li>- prolongs delay at AV node. </li></ul></ul><ul><ul><li>- has little effect on contractility. </li></ul></ul>
  62. 65. <ul><ul><li>Higher Centers of Autonomic Nervous System </li></ul></ul><ul><ul><ul><li>- Medulla Oblongata </li></ul></ul></ul><ul><ul><ul><li>- Hypothalamus, Thalamus, Cerebral cortex </li></ul></ul></ul>
  63. 66. Centers in Medulla Oblongata Sympathetic center: distinct accelerator and augmentor Parasympathetic center: Nucleus vagus and nucleus ambiguus
  64. 67. Hypothalamus, Thalamus, Cerebral cortex Involved in the cardiac response to environmental temperature changes, exercise , or during excitement , anxiety , and other emotional states
  65. 68. Neural Control via Reflexes
  66. 69. Baroreceptors
  67. 70. 1) Baroreceptor Reflex - stimulated by increase in arterial pressure (stretch) - Effect: negative chronotropic and inotropic - regulate the heart when BP increases or drops - involved in short term regulation of BP
  68. 71. 2) Chemoreceptor Reflex
  69. 72. Chemoreceptors Chemoreceptors Chemoreceptors
  70. 73. 2) Chemoreceptor Reflex - stimulated by  oxygen ,  pH , or  CO 2 - overall effect: positive choronotropic and inotropic. - less important in regulating cardiac function
  71. 74. 3) Proprioceptor Reflex - Stimulated by muscle and joint movement - Effects: increase heart rate during exercise
  72. 75. Regulation by Hormones <ul><li>Epinephrine </li></ul><ul><ul><li>- released from adrenal gland. </li></ul></ul><ul><ul><li>- increases heart rate and contractility. </li></ul></ul><ul><li>Thyroxin </li></ul><ul><ul><li>- released from thyroid gland. </li></ul></ul><ul><ul><li>- increases heart rate. </li></ul></ul><ul><li>  </li></ul>
  73. 76. Autoregulation of the Heart Stroke volume is autoregulated by ventricular filling ( Frank-Starling law ). SV More in More out
  74. 77. <ul><li>4) Other Factors </li></ul><ul><li>- Blood level of ionic calcium, sodium, and potassium </li></ul><ul><li>Hypercalcemia (high plasma Ca ++ ): </li></ul><ul><ul><ul><li>positive inotropic </li></ul></ul></ul><ul><ul><ul><li>Hypernatremia (high plasma Na + ): </li></ul></ul></ul><ul><ul><ul><li>negative chronotropic </li></ul></ul></ul><ul><ul><ul><li>Hyperkalemia (high plasma K + ): </li></ul></ul></ul><ul><ul><ul><li>negative chronotropic </li></ul></ul></ul><ul><ul><ul><li>used in lethal injection </li></ul></ul></ul>- Age, gender, exercise, and body temperature
  75. 78. Blood Supply to Cardiac Muscles
  76. 79. Can cardiac muscles get nutrients from the blood in heart chambers?
  77. 80. The cardiac muscles get nutrients from coronary circulation. Anterior view Posterior view
  78. 81. Coronary arterial anastomosis
  79. 82. Coronary venous blood is emptied into the right atrium through cardiac veins and coronary sinus. coronary sinus Posterior view
  80. 83. Blockade of coronary artery causes myocardial infarction , or heart attack .
  81. 84. Coronary Atherosclerosis
  82. 85. dull white and slightly elevated fibrous plaque ( atheroma ) on coronary arterial lumen. Typical lesion of Coronary Atherosclerosis
  83. 86.  composed of lipid, smooth muscle, macrophages, and connective tissues.  cause stenosis of coronary arteries Histology of the plaque    occlude arterial lumen when combined with internal hemorrhage, thrombosis, and arterial spasm
  84. 87.    occur often at arterial branching points
  85. 88. Surgical Therapies 1)
  86. 89. 2) Coronary angioplasty
  87. 90. 3) Stenting

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