title: Ultrastructure of the lining of the scala tympani of the bat, Pteronotus parnellii.
abstract: The cells lining the scala tympani of the cochlea of Pteronotus p. parnellii were studied in whole mount preparations and with light and scanning and transmission electron microscopy. On the basis of structure and location three different cell types were recognized: (1) those lying on the undersurface of the basilar membrane; (2) those covering the internal surface of most of the otic capsule; and (3) those associated with a thick layer of osmiophilic substance and restricted to a specific region in the basal turn. The cells associated with the osmiophilic substance were strikingly different from the other cells; they were relatively rich in organelles and had a Golgi complex which appeared to produce granules which coalesced both intracellularly and extracellularly to form the osmiophilic layer. The function and composition of the osmiophilic substance is unknown but it seems to be unique to Pteronotus parnellii and related subspecies known to have greatly enlarged perilymphatic scalae and unusual hearing capacities associated with Doppler shift compensation sonar.
mesh_terms: D000818:Animals; D001489:Basilar Membrane / Q000648:ultrastructure; D002462:Cell Membrane / Q000648:ultrastructure; D002685:Chiroptera; D003051:Cochlea / Q000033:anatomy & histology*; D003593:Cytoplasm / Q000648:ultrastructure; D003599:Cytoskeleton / Q000648:ultrastructure; D004912:Erythrocytes / Q000648:ultrastructure; D005089:Exocytosis; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009940:Organoids / Q000648:ultrastructure; D012533:Scala Tympani / Q000033:anatomy & histology*