Action Potentials

• The sequence of events

  • Initially the cell is resting at around -70 mV.
  • The cell becomes excited.
  • Channels open and the membrane permiability to sodium is suddenly increase greatly.
  • Sodium(Na+) rushes into the cell.
  • Voltage-activated Potassium channels open.
  • Permeability to Potassium (K+) increases slowly
  • Positive charges accumulate within the cell.
  • The membrane potential approaches the equilibrium potential for Sodium (E Na)
  • Na channels close
• Conduction velocities vary over a range of 100x with the most rapid being faster than 100 m/sec. Nicholls, Martin and Wallace's From Neuron to Brain page 132.

Back to general retina list

visit(s) to this page.