synaptic transmission

• AP reaches the presynaptic bulb

  1. Calcium channels open

  2. Influx of Ca+ ions into bulb
• Release of Ca+ ions


  Vesicles fuse with the presynaptic membrane
• Neurotransmitters diffuse across the synapse

  Neurotransmitters bind to sodium channels which act as receptors on the post synaptic neurone
• Neurotransmitter molecules not absorbed by the receptors of the post-synaptic neurone


  1. Destroyed by enzymes in the synaptic gap

  2. Reabsorbed into the pre-synaptic neurone via an uptake pump
• Reabsorbed molecules


  Destroyed by enzymes within the neurone to 'turn off' the neurone in preparation for a future action potential