Synapses

Where two neurons meet there is a small gap called a synapse.

An electrical impulse cannot directly cross the gap so a different mechanism has to be used.

  1. An electrical nerve impulse travels along the first axon.
  2. When the nerve impulse reaches the dendrites at the end of the axon, chemical messengers called neurotransmitters are released.
  3. These chemicals diffuse across the synapse (the gap between the two neurons). The chemicals bind with receptor molecules on the membrane of the second neuron.
  4. The receptor molecules on the second neuron can only bind to the specific neurotransmitters released from the first neuron.
  5. The binding of neurotransmitter to the receptors stimulates the second neuron to transmit an electrical impulse along its axon. The signal therefore has been carried from one neuron to the next.