Allows impulses to travel from one cell to the next without delay or loss of signal strength. Much less common than chemical synapses.
Examples are the giant neuron processes of crustaceans.
At a chemical synapse a synaptic cleft separates the pre- and postsynaptic cells so they are not electrically coupled. Within the cytoplasm of the synaptic terminal of a presynaptic cell are numerous synaptic vesicles containing thousands of neurotransmitter molecules. The neurotransmitter diffuses to the postsynaptic membrane where it binds to specific receptors, causing ion gates to open. Depending on the type of receptors and the ion gates they control, the neurotransmitter may either excite the membrane by depolarization or inhibit the postsynaptic cell by hyperpolarization. The neurotransmitter molecules are quickly degraded by enzymes and the components recycled to the presynaptic cell.