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Heart Physiology

Heart Physiology. Cardiac muscle characteristics. Conduction system of the heart. irritability. contractility. self-exciting. rhythmic. Conduction system of the heart. Medulla oblongata of brainstem and autonomic nervous system control heart rate. Control of the heart.

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Heart Physiology

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  1. Heart Physiology

  2. Cardiac muscle characteristics Conduction system of the heart irritability contractility self-exciting rhythmic

  3. Conduction system of the heart Medulla oblongata of brainstem and autonomic nervous system control heart rate Control of the heart Intrinsic control- SA node- cardiac muscle cells in RA, stimulated by neurons, stimulate other cardiac muscle cells

  4. Conduction system of the heart SA node (in RA)- “pacemaker” of cardiac cycle, sends impulses in atria to stimulate AV node Control of the heart AV node- (in RA) stimulates AV bundle (between ventricles), Purkinje fibers and ventricles

  5. Conduction system of the heart

  6. Cardiac cycle

  7. Cardiac Cycle Cardiac cycle= 1 complete heartbeat = .8 sec “Atrial systole with simultaneous ventricular diastole, then atrial diastole with simultaneous ventricular systole” Systole- contraction Diastole- relaxation

  8. Heart sounds- LUBB DUPP Cardiac cycle “LUBB”- AV valves (tricuspid and bicuspid) closing after atrial systole “DUPP”- semilunar valves (pulmonary and aortic) closing after ventricular systole

  9. Diagnostic technique EKG/ECG http://video.about.com/heartdisease/Electrocardiogram.htm

  10. Think back to nerve impulses and polarization, depolarization, repolarization P wave QRS complex T wave

  11. EKG/ECG flatlining

  12. Practical applicationsArtificial pacemaker If SA node is defective, then electronic device is implanted into heart to take SA node’s place

  13. CO= volume of blood pumped by LV per minute ml/min Practical applicationsCardiac output CO= stroke volume (SV) x heart rate (HR) SV= volume of blood pumped from LV per beat ml/beat HR= heart beats per minute b/min

  14. CO= amt of blood in body, because each drop of blood takes 1 minute to circulate through body Cardiac output sample problem Approx. 5 Liters= 5000ml Average fitness CO= SV x HR 5000ml/min = 67 ml/min x 75 b/min

  15. Cardiac output sample problems If a person is a couch potato….. resting CO of 5000ml/min Then 5000 ml/min= 50 ml/min x 100 b/min If they begin to exercise and are now of average fitness…… then resting CO= 5000ml/min = 67 ml/min x 75 b/min

  16. Cardiac output sample problems If they become even more fit or active and resting CO= 5000ml/min = Then 5000ml/min= 83 ml/min x 60 b/min As person becomes more fit- heart becomes more fit at rest, pumps less beats per min., but more blood per beat

  17. Regulation of SV and HR- can be affected by exercise and fitness level Cardiac output Exercise and fitness level- as a person’s fitness level increases, their HR decreases, SV increases, but resting CO can stay the same unless they have more or less blood

  18. Angina pectoris- chest pain, can be symptom of MI Homeostatic imbalances Heart attack (myocardial infarction)- due to blocked coronary artery

  19. Pain areas in red Angina Pectoris treatment

  20. Myocardial infarctionAKA heart attack

  21. Myocardial infarction anticoagulants

  22. Homeostatic imbalances Murmurs- occurs if valves don’t close correctly or leak Fibrillation- if atria or ventricles don’t contract simultaneously

  23. Heart Murmurs

  24. EKG/ECG of atrial fibrillation

  25. Ventricular fibrillation Can lead to death because ventricles tremble, but don’t contract, so n0 blood flow

  26. Shocks heart to “reset” it Defibrillator Defibrillator

  27. MVP- bicuspid valve leaks, blood flows backwards Homeostatic imbalances Pericarditis- inflammation of pericardium around heart

  28. MVP- mitral valve prolapse

  29. Pericarditis

  30. Cardiac arrhythmia- irregular heart beat, due to fibrillation or SA node problems Homeostatic imbalances CAD- plaque/cholesterol in coronary arteries

  31. Cardiac arrhythmia Irregular heart beat

  32. Of coronary arteries Coronary artery disease HDL’s- good cholesterol LDL’s- bad cholesterol- clogs arteries

  33. Coronary artery disease

  34. Coronary artery disease Catheterization is a treatment, not a cure, because if one doesn’t change eating habits then it will just happen again

  35. Homeostatic imbalances CHF- heart weakening, not necessarily stoppage

  36. Due to: MI Atherosclerosis Hypertension CAD Other heart diseases CHF-congestive heart failure

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