Neurons do not make direct contact but are separated by synapses. Impulses cross a synapse by means of a neurotransmitter. Describe the process of neurotransmitter release at a synapse. You may use a labelled diagram.

  1. Action potential arrives at axon terminal of presynaptic neuron

  2. Voltage-gated Ca2+ channel opens

  3. Ca2+ enters the cell

  4. Ca2+ signals to vesicles

  5. Vesicles move to the membrane

  6. Neurotransmitters are released by exocytosis

  7. Neurotransmitters diffuse across the synaptic cleft and bind to receptors on the postsynaptic membrane

CM

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