Regions of interest and characterisation of the cell types counted in the vestibule in Haematoxylin and Eosin stained sections. A) Vestibular regions analysed. CA: crista ampullaris in posterior semicircular canal ampulla, U: utricular macula, Sa: macula of saccule. 10x magnification, scale bar = 200 µm. B) Cell types. I: Normal type I hair cell characterized by a spherical nucleus with substantially heterogeneous chromatin, a thick nerve branch (N) surrounded by flask-shaped nerve calyx (NC) with a narrowing toward the cuticular plate (CP), and stereocilia (St). II: Type II hair cell characterized by cylindrical shape, oval nucleus with substantially homogenous chromatin, nerve branch (n) without a nerve calyx surrounding the cell body, and spatial location closer to the cuticular plate than supporting cells. S: Supporting cell characterized by a nucleus with chromatin material distributed in clumps, spatial location adjacent to the basal lamina, and a lack of stereocilia or cuticular plate. 100x magnification, scale bar = 20 µm.