ICS + ECG

• ECG:

  1. sinoatrial node generates action potential, causing excitation of the atria
  2. action potential delayed at the atrioventricular node
  3. action potential passes to the apex of the heart, starting excitation og the ventricles
  4. excitation of the ventricles occur

  
• ECG:

  • 3 waves - represent the spread of electrical activity/action potentials within the heart
  • P wave - depolarisation of atria
  • QRS complex - depolarisation of ventricles
  • T wave - repolarisation of the ventricles and cycle can repeat
  • isoelectric periods - means there is no ion influx
  • PR interval - PQ isnt as visible, so PR is the measure, but still measured from beginning of P wave to beginning of QRS complex
  • ST

  A) P

  B) Q

  C) R

  D) S

  E) T

  F) PR

  G) ST

  
• 1. sinoatrial node causes atria to depolarise during P wave
  2. atrioventricular node delays action potential during PQ interval
  3. after 0.1 seconds the action potential moves to the bundle of His, causing depolarisation of the ventricles, shown by the QRS complex
  4. ST interval shows the end of depolarisation of the ventricles, where there is no ion influx
  5. T wave shows repolarisation of the ventricles occurring, starting from the apex of the heart
  6. repolarisation of the ventricles is complete