A chemical synapse functions to convert an electrical signal (action potential) into a chemical signal through neurotransmitter release. It is composed of a presynaptic and postsynaptic terminal. The presynaptic terminal is located at the end of an axon, and is the region where the action potential is converted into a chemical signal via neurotransmitter release. A synapse is located at the junction between two neurons. The action potential causes one neuron to release a chemical neurotransmitter. This neurotransmitter can either assist to excite or inhibit the subsequent neuron from firing another action potential of its own. Once the neurotransmitter reaches an adjacent neuron, the chemical signal is converted back to an action potential. The action potential then travels along the neuron and passes the signal to the next synapse. This process occurs continuously in the central nervous system. Chemical synapses are also the most prevalent type of synapse in the body.
An electrical synapse is the simpler type of synapse, as there are no gaps between the cells. Ions move directly through structures known as gap junctions, permitting them to pass an electrical signal to the adjacent neuron. Electrical synapses are faster compared to chemical synapses, since the current flow across gap junctions is immediate. These synapses do not have synaptic delay, which chemical synapses do have. It is important to note that electrical synapses do not involve neurotransmitters.