Chemical synapse.

  1. Voltage-gated Ca2+ channels in the presynaptic membrane open in response to an action potential.

  2. Ca2+ ions flow in.

  3. Synaptic vesicles fuse with presynaptic membrane of the synaptic terminal, releasing neurotransmitters.

  4. Neurotransmitters diffuse across synaptic cleft and bind to ligand-gated channels in the postsynaptic membrane.

  5. Ions flow in and generate a postsynaptic potential.

  6. Neurotransmitters release from channels, which close.