The morphological structure of the chick's basilar papilla: a light and transmission electron microscopic study

Abstract

The basilar papilla corresponds to the cochlea of mammals and is becoming a common model of assessment of the regeneration process which takes place after the damage to the inner ear caused by noise or ototoxic drugs. In this study the morphology of a chick's basilar papilla in light and electron microscopy is described. There are two types of hair cells (sensory cells): the tall hair cells and the short hair cells, whose morphology and pattern of innervation are different. The tall hair cells correspond to the inner, hair cells in mammals, which are responsible for sound transduction. They are mainly innervated by the afferent (cochlear) fibers. The short hair cells correspond to the outer hair cells in mammals, which are responsible for the sound amplification. They are mainly innervated by the efferent fibers. The supporting cells, whose morphology is also described in the study, separate the hair cells from each other and from the basilar membrane. They are considered to be a source for regenerating hair cells.