Sequence of chemical events at a synapses

• Synaptic cleft


  The space between the presynaptic and postsynaptic neuron
• Neurons synthesize chemicals called neurotransmitters
• Neurotransmitters


  1. Attach to receptors

  2. Alter activity of the postsynaptic neuron

  3. Separate from their receptors

  4. Converted into inactive chemicals
• Action potentials


  1. Travel down the axon

  2. Cause calcium to enter the cell

  3. Lead to the release of neurotransmitters from the terminal into the synaptic cleft
• Some postsynaptic cells send negative feedback messages to slow further release of the transmitter by the presynaptic cells
• Fate of neurotransmitters

  • Taken back into the presynaptic neuron for recycling
  • Empty vesicles are returned to the cell body
• Presynaptic terminal


  The end of the axon where neurotransmitters are released