Synapse. Computer artwork of a synapse, the junction between two nerve cells. Other nerve cell bodies are present. Synapses transmit electrical signals from one nerve cell to the next. When an electrical signal reaches a synapse it triggers the release of chemicals called neurotransmitters (blue spheres) from vesicles (pink) in the terminal swelling of the presynaptic cell. The vesicles burst through the membrane, & neurotransmitters cross a microscopic gap called the synaptic cleft, and bind to the receptor nerve cell. The neurotransmitter changes the permeability of the postsynaptic membrane, causing it to propagate an electrical impulse.