Action Potential

• 1 - energy from stimulus triggers Na+ channels to open, ions diffuse in
• 2 - causes more Na+ channels to open, positive feedback
• 3 - depolarisation

  pd reaches +40mv
• 4 - causes Na+ channels to close, K+ open
• 5 - too many K+ diffuse out, so internal too -

  hyperpolarisation
• 6 - causes K+ channels to close
• 7 - Na-K pump returns charge to normal resting state in 3:2 ratio

  repolarisation