The Sensory Hairs and the Tectorial Membrane in the Development of the Cat's Organ of Corti:A Scanning Electron Microscopic Study

The surface topography of the organ of Corti has been studied by scanning electron microscopy. Newborn kittens of various ages as well as adult cats were included in this study. In the newborn kitten all the sensory cells have one kinocilium in addition to the bundle of stereocilia. This kinocilium most frequently is short and looks rudimentary; however, some of the kinocilia are even longer than the longest of the stereocilia. The distal end often shows a bulb-like thickening. Within a few weeks after birth, all the kinocilia disappear. The relationship between the outer margin of the tectorial membrane and the epithelial surface has been investigated. In the kitten the tectorial membrane is firmly attached at its outer margin to the upper, free surfaces of the outermost row of Deiters' cells. There is no such attachment in the cat six weeks of age nor in the adult cat. This may have functional implications.