Contact site between axon and nerve cell, with chemical transmission of information across the synaptic cleft from the axon of a presynaptic neurone to the axon, dendrite or cell body of a postsynaptic neurone (or sometimes from one dendrite to another). There are two main types of synapses: axodendritic synapses between one axon and the dendrite of another that are mainly has an excitatory effect on the target neuron, and axiomatic synapses between an axon and the soma of a cell that usually exerts an inhibitory effect. Less frequently occurring are axoaxonic synapse between the axon of an inhibitory neuron and the axon of the neuron that they inhibit. The term ‘synapse’ was derived by Sherrington from the Greek words syn meaning ‘altogether’ and haptein standing for ‘to clasp’. It should be remembered that in addition to chemical synapses there are also electrical and immunological synapses.
See Action potential, Axon, Boutons, Dendrite, Denervation, Human Connectome Project (HCP), MECP2 gene, Motoneuron, Motor end plate, Neuromuscular junction, Neuron doctrine, Neurotransmitters, Nissl substance, Synaptic cleft, Synapse elimination, Synapse stabilization