Transmission of Nerve Impuses

• Transmission of Nerve Impulses

  1. Action potential triggered in neurone

  2. Depolarisation of axon section

  3. Sodium ion channels open

  4. Influx of sodium ions

  5. Action potential generated in next section

  6. Previous section in repolarisation stage and unresponsive
• Transmission along an axon

  • Action potentials are discrete events
  • Impulse can only travel in one direction
• All or nothing principle

  If receptor stimulus is below threshold, no impulses are sent<|>If receptor stimulus is above threshold, impulses are sent
• Strength of stimulus

  • Receptor potential increases
  • Frequency of impulses increases
• In myelinated axons, depolarisation only occurs at the nodes but still occurs in one direction as the previous node is in the repolarisation stage