Tag Archives: Cardiac muscle


Electrical Activity and EKG

The Cardiac Action Potential Has a Prolonged Refractory Period

  • Heart action potential has a prolonged spike (depolarized)
  • Membrane is refractory for a long time
  • This prevents summation and gives the heart time to fill

All Parts of the Heart Beat Spontaneously

  • Heart muscle does not require stimulation by a nerve
  • Nerves usually inhibit the heart beat; cutting the nerves -> heart speeds up
  • Beat originates as a depolarization in the heart muscle cell itself (self stimulation)
  • All parts of the heart can beat spontaneously