Class 11 Biology Body Fluids Circulation Electrocardiograph (ECG)

 

  • ECG is a graphical representation of the electrical activity of the heart during a cardiac cycle.
  • To obtain a standard ECG, a patient is connected to the machine with three electrical leads, one to each wrist and to the left ankle, that continuously monitor the heart activity.
  • Each peak in the ECG is identified with a letter from P to T that corresponds to a specific electrical activity of the heart.
  • The P-wave represents the electrical excitation (or depolarisation) of the atria, which leads to the contraction of both the atria.
  • The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction.
  • The T-wave represents the return of the ventricles from excited to normal state (repolarisation) and the end of the T-wave marks the end of systole.
  • By counting the number of QRS complexes that occur in a given time period, one can determine the heart beat rate of an individual.

Class_11_Biology_Body_Fluids_&_Circulation_Electrograph

Fig. Electrocardiograph

Share these Notes with your friends  

< Prev Next >

You can check our 5-step learning process


.