Figure 7: The ribbon synapse of the inner hair cell. The afferent synapse of the inner hair cells (HC) consists of a presynaptic active zone with the synaptic ribbon (diameter 0.2 µm), a protein nanomachine to which the synaptic vesicles (diameter 35-40 nm) are bound. The postsynaptic nerve fibre ending contains numerous ionotropic AMPA-type glutamate receptors (AMPA-R). Each active zone contains some 50 CaV1.3 calcium channels and 30 glutamate-containing synaptic vesicles (SV). Abbreviations: SC (supporting cells), (Figure modified after Fuchs et al. [120]).