Micro-dissection of a left human temporal bone. The cochlea has been opened and the round window can be seen inferiorly. Infero-lateral view.The same image as above. A floating mass transducer (FMT) has been applied in the widened round window niche.Plastic corrosion casts of the human cochlea. There are extensive anatomical variations.Scanning electron microscopy av hemisectioned human cochlea after decalcification in 0.1M Na-EDTA.White labeled ring denotes the position of the spiral ganglion neurons within the modiolus innervating the basal turn hair cells. Yellow arrow shows the helicotrema or the region where the scala tympani and scala vestibuli meet in the apex of the cochlea.Higher magnification of framed are seen in the image above. The organ of Corti rests on the basilar membrane. Above the Reissners membrane can be seen. It separated the scala vestibuli from the endolymphaytic space of the scala media. The tectorial membrane can also be seen.Immunohistochemistry showing of distribution of the connexin 30 in the lateral wall of the human cochlea. There is a rich expression of Cx30 in the spiral ligament accumulating against the stria vascularis. Expression of the neural marker TUJ1 can also be seen in neurons reaching the organ of Corti.Confocal microscopy showing the distribution of connexin 26 (red) and 30 (green) in the human organ of hearing (organ of Corti). There is a rich patchy distribution of Cx30 in the supporting cells while the distribution of Cx26 is more diffuse and intracellular, particularly in the outer pillar and Deiter cells.Scanning electron microscopy of a human organ of hearing. The human sensory hair cells are seen (blue; outer hair cells and red; inner hair cells). These cells are surrounded by many different supporting cells. The human cochlea contains 15 000 hair cells. Only the inner hair cells (3400, red) transmit nerve signals to the brain. The outer hair cells (12000) exhibit the protein prestin (red labeling). It is expressed immunohistochemically in the cell membrane (A,B,C) and can be visualized with laser confocal microscopy. The cell cytoplasm is visualized through a marker targeting parvalbumin.