Olfactory cilia in the frog

Abstract

Olfactory epithelium from the frog was examined in the living state by light microscopy and in the fixed statc by electron microscopy. Particular attention was paid to the layer of cilia and mucus which covers the surface of the epithelium. The olfactory cilia differed from typical cilia in that thcy (a) arose from bipolar neurons and had ccntrioles ncar their basal bodies, (b) were up to 200 microns in length, of which the greater part was a distal segment containing an atypical array of ciliary fibers, (c) wcre ohcn immotile, (d) had their distal segments arranged in parallcl rows near the surface of the mucus, and (e) had many vesicles along their shahs and had splits in the array of fibers in their distal segments. These specializations make the olfactory cilia similar to cilia found on other sensory cclls and support the theory that they are the locus where electrical excitation in the olfactory organ is initiated by contact with odorous substances. © 1965, Rockefeller University Press., All rights reserved.