BIOL 121 Chp 20: The Cardiovascular System - The Heart

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This is a lecture presentation for my BIOL 121 Anatomy and Physiology I students on Chapter 20: The Cardiovascular System: The Heart (Principles of Anatomy and Physiology, 14th Ed. by Tortora and Derrickson).

Rob Swatski, Associate Professor of Biology, Harrisburg Area Community College - York Campus, York, PA. Email: rjswatsk@hacc.edu

Please visit my website for more anatomy and biology learning resources: http://robswatski.virb.com/

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BIOL 121 Chp 20: The Cardiovascular System - The Heart

  1. 1. 1   Rob  Swatski   Associate  Professor  of  Biology   HACC  –  York  Campus   Chapter  20     Cardiovascular   System:       The  Heart   Textbookimages-Copyright© 2014JohnWiley&Sons,Inc. Allrightsreserved.
  2. 2. 20_03a   2  
  3. 3. 3  
  4. 4. 4  
  5. 5. 5  
  6. 6. (a) Inferior view of transverse section of thoracic cavity showing heart in mediastinum Sternum Muscle Left lung Esophagus Sixth thoracic vertebra LEFT PLEURAL CAVITY Heart PERICARDIAL CAVITY Right lung Aorta RIGHT PLEURAL CAVITY POSTERIOR ANTERIOR View Transverse plane Pulmonary trunk (artery) Heart  LocaEon:  MediasEnum  
  7. 7. Arch of aorta Anterior  view  of  heart  in  thoracic  cavity   Pulmonary trunk Left lung LEFT SURFACE APEX OF HEART Superior vena cava RIGHT SURFACE Right lung Pleura (cut to reveal lung inside) Diaphragm INFERIOR SURFACE Heart
  8. 8. 8   Heart   OrientaEon   Apex:  anteriorly,  inferiorly,  le6-­‐side   Base:  posteriorly,  superiorly,  right-­‐side     Anterior  surface:  deep  to  sternum  &  ribs   Inferior  surface:  on  diaphragm       Right  border:  faces  right  lung   LeK  (Pulmonary)  border:  faces  le6  lung  
  9. 9. 9   Heart  Surface  ProjecEon   Superior  right  point:  sup  border  -­‐  3rd  right  costal  carClage     Superior  leK  point:  inf  border  -­‐  2nd  le6  costal  carClage,  3  cm  le6  of  midline     Inferior  leK  point:  5th  intercostal  space,  9  cm  le6  of  midline     Inferior  right  point:  sup  border  -­‐  6th  right  costal  carClage,  3  cm  right  of  midline  
  10. 10. 10   Pericardium       Fibrous  pericardium  (outer)    -­‐  dense  irregular  CT    -­‐  protects  &  anchors  heart    -­‐  prevents  overstretching     Serous  pericardium   (epicardium):    -­‐  thin,  delicate  membrane    -­‐  parietal  &  visceral  layers    -­‐  pericardial  cavity      -­‐  pericardial  fluid    
  11. 11. PericardiEs   Cardiac  tamponade   11  
  12. 12. 12   Layers  of  the  Heart  Wall   Epicardium:  2  layers  –  1)  visceral  layer  of  serous  pericardium  &  2)   adipose  Cssue  &  fibroelasCc  Cssue     Myocardium:  cardiac  muscle       Endocardium:  endothelium  &  CT  (lines  chambers  &  valves)  
  13. 13. 13   Muscle  Bundles  of  the  Myocardium  
  14. 14. 14   MyocardiEs  &  EndocardiEs   endocardiEs   myocardiEs  
  15. 15. 15   Chambers  &  Sulci  of  the  Heart   4  Chambers:     -­‐  2  superior  atria   -­‐  2  inferior  ventricles     Sulci:  grooves  on  heart  surface    -­‐  contain  coronary  BVs  &  adipose       Coronary  sulcus    -­‐  encircles  heart  b/w  atria  &  ventricles       Anterior  interventricular  sulcus      -­‐  ant.  boundary  b/w  ventricles       Posterior  interventricular  sulcus      -­‐  post.  boundary  b/w  ventricles  
  16. 16. 16  
  17. 17. 17  
  18. 18. 18  
  19. 19. 19   Right  Atrium   Receives  blood  from  3  sources:   superior  vena  cava,  inferior  vena  cava,  &  coronary  sinus     Interatrial  septum     Fossa  ovalis:  remnant  of  fetal  foramen  ovale     Tricuspid  valve   -­‐  blood  flows  through  into  right  ventricle   -­‐  3  cusps  of  dense  CT   -­‐  “RAT  on  the  Right”  (Right  Atrioventricular,  Tricuspid)  
  20. 20. 20   Right  Ventricle   Forms  most  of  ant.  surface  of  heart   Interventricular  septum   Trabeculae  carneae   Papillary  muscles   Chordae  tendineae     Pulmonary  semilunar  valve   -­‐  allows  blood  into  pulmonary  trunk    
  21. 21. Papillary  Muscles  &     Chordae  Tendineae   21  
  22. 22. 22  
  23. 23. 23   LeK  Atrium   Forms  most  of  base  of  heart     Receives  blood  from  lungs  through  4  pulmonary  veins   -­‐  2  right  &  2  le6     Bicuspid  valve:  blood  flows  through  into  le6  ventricle   -­‐  2  cusps   -­‐  “LAMB  on  the  Le6”:  Le6  Atrioventricular,  Mitral,  or  Bicuspid  
  24. 24. 24   LeK  Ventricle   Forms  apex  of  heart       Chordae  tendineae,  papillary  muscles,  &  trabeculae   carneae     AorEc  semilunar  valve   -­‐  allows  blood  into  ascending  aorta   -­‐  openings  to  the  coronary  arteries  directly  above  valve  
  25. 25. 25   Myocardial  Thickness  &  FuncEon   Thickness  varies  based  on  each  chamber’s  funcCon:    -­‐  Atria  walls  are  thin;  Ventricle  walls  are  thick    -­‐  Right  ventricle  walls  are  thin;  LeK  ventricle  walls  are   thick  
  26. 26. 26   Fibrous  Skeleton  of  Heart   Dense  CT  rings  surround  heart  valves   -­‐  fuse  together  &  merge  with  interventricular  septum     FuncEons  of  fibrous  skeleton:      -­‐  valve  support  structure   -­‐  Prevents  overstretching  of  the  valves    -­‐  inserCon  point  for  cardiac  muscle  bundles    -­‐  electrical  insulator  b/w  atria  &  ventricles  
  27. 27. 27   AV  Valves  OPEN   Allow  blood  flow  from  atria  into  ventricles   when  ventricular  pressure  is  lower  than   atrial  pressure   Occurs  during  ventricular  relaxaEon:    -­‐  papillary  muscles  are  relaxed    -­‐  chordae  tendineae  are  slack  
  28. 28. 28  
  29. 29. 29   AV  Valves  CLOSED   Prevents  backflow  (regurgita/on)  of  blood  into  atria     Occurs  during  ventricular  contracEon:    -­‐  papillary  muscles  contract      -­‐  chordae  tendineae  pulled  taut    -­‐  valve  cusps  pushed  closed    
  30. 30. 30   SL  valves  OPEN  during  ventricular  contracCon    -­‐  allow  blood  flow  into  pulmonary  trunk  &  aorta     SL  valves  CLOSE  during  ventricular  relaxaCon    -­‐  blood  fills  cusps  &  valves  close    -­‐  prevents  blood  from  flowing  backwards  into   ventricles   Semilunar   Valves  
  31. 31. Superior view with atria removed: pulmonary and aortic valves closed, bicuspid and tricuspid valves open PULMONARY VALVE (closed) Left coronary artery BICUSPID VALVE (open) TRICUSPID VALVE (open) AORTIC VALVE (closed) Right coronary artery POSTERIOR ANTERIOR
  32. 32. 32  
  33. 33. 33  
  34. 34. 34   Heart  Valve  Disorders   Stenosis:  narrowing  of  valve  that  restricts  blood  flow   -­‐  Surgically  repaired  or  replaced  with  mechanical  valves  or   valves  from  human  donors  or  pigs     Insufficiency  or  incompetence:  valve  cannot  close  completely   Balloon     valvuloplasty  
  35. 35. Mitral  Valve  Stenosis   35  
  36. 36. 36   Systemic  CirculaEon   LEFT  side  of  heart  pumps  oxygenated  blood  to  body     LeK  atrium  à  LeK  ventricle  à  Aorta  à  Systemic  arteries  à   Arterioles  à  Systemic  capillaries  à  Organsà  Systemic   venules  à  Systemic  veins  à  Superior/Inferior  vena    cava/Coronary  sinus  à  Right  atrium          
  37. 37. 37   Pulmonary  CirculaEon   RIGHT  side  of  heart  pumps  deoxygenated  blood  to  lungs       Right  atrium  à  Right  ventricle  à  Pulmonary  trunk  à  Pulmonary   arteries  à  Pulmonary  capillaries  à  Lungs  à  Pulmonary  Veins      
  38. 38. 38  
  39. 39. Oxygen-rich blood Path  of  blood  flow  through  heart   Oxygen-poor blood 10. 8. 5. 7. 2. 1. 3. 5. 6. 10. 4. Pulmonary capillaries of right lung Key: 4. Pulmonary capillaries of left lung 9. Systemic capillaries of head and upper limbs 9. Systemic capillaries of trunk and lower limbs
  40. 40. 40  
  41. 41. 41   Coronary   CirculaEon   Blood  flow  into   the  myocardium   Supplies  the   cardiac  muscle   Cssue  of  the   heart  wall   Many   anastomoses  
  42. 42. 42  
  43. 43. 43   Coronary  Arteries   Right  coronary   artery   Marginal  branch   Posterior   interventricular  branch   LeK  coronary   artery   Anterior   interventricular  branch   or  Le6  anterior   descending  (LAD)   Circumflex  branch  
  44. 44. 44  
  45. 45. 45  
  46. 46. 46   Coronary   Veins   Collect  wastes  from   myocardium   Great  cardiac  vein,   Middle  cardiac  vein,   Small  cardiac  vein,   Anterior  cardiac  vein   Drain  into  coronary   sinus  
  47. 47. 47   Cardiac   Muscle   Tissue   Striated,   branching,   shorter  fibers  of   heart   Intercalated   discs  with  gap   juncEons   One  central   nucleus  per  fiber  
  48. 48. 48   Cardiac  Muscle  Histology  
  49. 49. 49   Cardiac   Muscle   Tissue   Same  acCn  &   myosin   arrangement  as   skeletal  muscle   Autorhythmic   Longer   contracCons   (longer  Ca+2   delivery)  
  50. 50. 50   Cardiac  Myofibril  
  51. 51. 51   ConducEon   System   Autorhythmic   fibers  à   spontaneous  APs   Propagate  APs   through   myocardium   Sinoatrial  (SA)   node  =   pacemaker  
  52. 52. 52   SA  node   AV  node   AV  bundle  (of   His)   Right  &  leK   bundle  branches   Purkinje  fibers   ConducEon  System  
  53. 53. 53  
  54. 54. 54  
  55. 55. 55   RegulaEon  of  the   ConducEon   System   Autonomic   Nervous  System   (ANS)   Hormones   (epinephrine)   Modify  heart   rate  &  strength   of  contracCon   They  do  NOT   establish  the   fundamental   rhythm  
  56. 56. 56   AcEon   PotenEal   DepolarizaEon   Plateau   RepolarizaEon   Refractory   period  
  57. 57. 57   Physiology  of  ContracEon  
  58. 58. 58  
  59. 59. 59   Electro-­‐ cardiogram   (ECG  or  EKG)   Visual  record  of  all  APs   during  each  cardiac   cycle  (heartbeat)   Detected  at  body’s   surface   DiagnosCc  value   Detects  abnormal   conducCon,   enlargement,  muscle   damage,  &  reasons  for   chest  pain  
  60. 60. 60   ECG   P  wave   QRS   complex   T  wave  
  61. 61. 61   DiagnosEc   Value  of   the  ECG   P-­‐Q   interval   S-­‐T   segment   Q-­‐T   interval  
  62. 62. Ventricular diastole (relaxation) 6 Repolarization of ventricular contractile fibers produces T wave 5 Ventricular systole (contraction) 4 Depolarization of ventricular contractile fibers produces QRS complex 3 Atrial systole (contraction) 2 Depolarization of atrial contractile fibers produces P wave 1 Action potential in SA node P P P P P P R Q S T
  63. 63. 63  
  64. 64. 64  
  65. 65. 65  
  66. 66. 66  
  67. 67. 67   Cardiac  Cycle   Systole  =   ContracCon   Diastole  =   RelaxaCon   At  75  beats/min,  1   cycle  =  0.8  sec   Pressure  &  volume   changes  during   cycle   Blood  pumped   from  high  to  low   pressure  areas  
  68. 68. 68   Atrial  systole   (contrac'on)   Atrial  diastole   (relaxa'on)   Ventricular   systole   Ventricular   diastole   Cardiac  Cycle  
  69. 69. 69   Blood   Volumes   End  Diastolic   Volume  (EDV)   =  130  ml   End  Systolic   Volume  (ESV)   =  60  ml   Stroke   Volume  (SV)   =  70  ml  
  70. 70. 70   SV  =  EDV  -­‐  ESV  
  71. 71. 71   Phases  of  the   Cardiac  Cycle   Isovolumetric   RelaxaEon   (all  valves  close)   Ventricular   Filling     (AV  valves  open)   Isovolumetric   ContracEon     (AV  valves  close)   Ventricular   EjecEon     (SL  valves  open)  
  72. 72. 72  
  73. 73. 73  
  74. 74. 74   Ventricular   Pressures   AorCc  BP  =   120  mmHg   Pulmonary   trunk  BP  =   30  mmHg   Why?    How?  
  75. 75. 75  
  76. 76. 76   Heart  Sounds   AuscultaEon   Produced  when   valves  close   S1:  “lubb”  =  AV   valves  close   (louder,  longer)   S2:  “dupp”  =  SL   valves  close   (quiet,  shorter)  
  77. 77. 77   Heart   Sounds  
  78. 78. 78   Heart   Murmurs   Abnormal   sounds  before,   b/w,  or  a6er   normal  sounds   May  also  mask   normal  sounds   Caused  by  valve   disorders   (stenosis,   incompetency)  
  79. 79. 79   Cardiac   Output   Volume  of  blood   ejected  each   minute  from  either   ventricle   CO  =  Stroke   Volume  (SV)  x   Heart  Rate  (HR)     70  ml  SV  x  75   beats/min  =   5.25  L/min   Cardiac  reserve  
  80. 80. 80   RegulaEon  of   Stroke  Volume   Preload   ContracElity   AKerload  
  81. 81. 81   Preload   The  greater  the   stretch,  the   greater  the  force   of  contracCon   The  greater  the   blood  volume,  the   greater  the  force   of  contracCon   Frank-­‐Starling   Law  of  the  Heart  
  82. 82. 82   ContracElity   PosiEve  inotropic   agents   SCmulaCon  of  he   SympatheCc  division  of   the  Autonomic  Nervous   System  (ANS)   Hormones:  epinephrine  &   norepinephrine   Higher  intersCCal  Ca+2   Drugs  (digitalis)  
  83. 83. 83   ContracElity   NegaEve   inotropic  agents   InhibiCon  of  the   SympatheCc  division  of   the  Autonomic  Nervous   System  (ANS)   Anoxia,  acidosis,  some   anestheCcs   Higher  intersCCal  K+   Drugs  (Calcium  channel   blockers)  
  84. 84. 84   AKerload   The  back  pressure   in  the  arteries  that   the  ventricles   must  overcome…   …in  order  to  open   the  semilunar   valves   The  greater  the   BP  =  the  greater   the  a6erload  
  85. 85. 85   CongesEve   Heart  Failure   If  a6erload  is  high,   more  blood  remains   in  the  ventricles…   …which  increases  the   preload   Le?  ventricular   failure  =  pulmonary   edema   Right  ventricular   failure  =  peripheral   edema  
  86. 86. 86  
  87. 87. 87   Neural   RegulaEon  of   Heart  Rate   Cardiovascular   center  in  medulla   oblongata   SympatheEc   impulses  increase   HR  &  force  of   contracCon   ParasympatheEc   impulses   decrease  HR  
  88. 88. 88   Nervous   System   Receptors   Proprioceptors:   monitor   movements   Chemoreceptors:   monitor  blood   chemistry     Baroreceptors:   monitor  BP  
  89. 89. Cardiovascular (CV) center Key: Sensory (afferent) neurons Motor (efferent) neurons Medulla oblongata Glossopharyngeal nerves (cranial nerve IX) Vagus nerves (cranial nerve X, parasympatheti c) SA node Sympathetic trunk ganglion Cardiac accelerator nerve (sympathetic) Ventricular myocardium AV node Baroreceptors in arch of aorta Baroreceptors in carotid sinus Spinal cord
  90. 90. 90  
  91. 91. 91   Biochemical   RegulaEon  of   Heart  Rate   Oxygen  level:  hypoxia   pH:  acidosis  and   alkalosis   Hormones:  Epinephrine,   norepinephrine,  thyroid   hormones   CaEons:  Na+,  K+,  Ca+2   Other  factors:  Age,   gender,  physical  fitness,   body  temperature,  stress  
  92. 92. 92  
  93. 93. 93   High  blood   cholesterol   High  BP   Smoking   Obesity   Lack  of   regular   exercise   Family  history   Male  gender   Diabetes   Le6   ventricular   hypertrophy   Risk  Factors  for  Heart  Disease  
  94. 94. 94   Plasma  Lipids   &  Heart   Disease   High  blood   cholesterol:   promotes  plaques   High-­‐Density   Lipoproteins   (HDLs)   Low-­‐Density   Lipoproteins   (LDLs)   Very  Low-­‐Density   Lipoproteins   (VLDLs)  
  95. 95. 95   Coronary  Artery  Disease   (CAD)   Ischemia   Reduced  blood   flow  through   coronary  arteries   Causes  hypoxia   &  weakens   cardiac  muscle   Angina   Pectoris   Narrowing  of   coronary  arteries   Leads  to  reduced   blood  flow,  chest   pain,  pressure,   discomfort   Myocardial   InfarcEon   Complete   obstrucCon  of   coronary  blood   flow  causing  heart   amack  
  96. 96. 96  
  97. 97. 97   Coronary   Artery  Disease   ObstrucEons   Atherosclerosis   Coronary  artery   spasm   Coronary  artery   thrombosis  
  98. 98. 98   Coronary   Artery  Bypass   GraKing   (CABG)  
  99. 99. 99  
  100. 100. 100  
  101. 101. 101   Congenital  Heart  Defects  
  102. 102. 102   Congenital  Heart  Defects,  cont.  
  103. 103. 103   Arrhythmia   Irregularity  in  heart   rhythm  due  to   conducCon  system   defect   Bradycardia   Tachycardia   FibrillaEon  
  104. 104. (d) Ventricular tachycardia Ventricular fibrillation (e) Ventricular fibrillation Ventricular tachycardia
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