Electron micrographs of synaptic ribbons in IHCs and OHCs of P7–P9 rat cochleae (apical turn). A, Synaptic ribbon in an IHC (P7 rat). B, Synaptic ribbon in an IHC (P9 rat). C, Serial reconstruction (4 sections) of IHC ribbon from A. D, Synaptic ribbon in an OHC (P9 rat). E, Synaptic ribbon in a different OHC (P9 rat). F, Serial reconstruction (4 sections) of OHC ribbon from D. Reconstructions (C, F) show ribbon in turquoise, hair cell membrane in green, vesicles in yellow and afferent in burnt orange. Scale bars, 200 nm.