cardiac cycle phases

  • Created by: cat
  • Created on: 05-05-15 16:07

1) Quiescent period.

  • none of chambers contracting 
  • blood flows in to atria directly in to ventricles through open atrioventricular valves.

2) Atrial systole.

  • Atria depolarise [P wave] and contract.
  • additional blood forced into ventricles
  • at end of phase, end diastolic volume = 130ml blood 
  • 70% of end diastolic volume enters passively during quiescent phase
  • last 30% added by atrial systole

3) Isovolumetric contraction

  • Atria relax, remain is diastole for rest of the cycle
  • ventricles depolarise [QRS] and contract
  • ventricular pressure ries rapidly 
  • atrioventricular valves close 
  • contraction…


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