- An electrical impulse travels down the axon of a pre-synaptic neurone. - The movement of this electrical impulse initiates the release of chemical messengers which are called neurotransmitters. - The neurotransmitters move across the gap between the pre-synpatic neurone and post-synaptic neurone by means of diffusion. - The gap between the pre-synaptic and post-synaptic neurone is referred to as the synapse. - On the post-synaptic neurone, receptor cells recognise and recieve the neurotransmitter emitted from the pre-synaptic neurone. - As a result, this causes the continuation of the electrical impulse across the post-synaptic synaspe.