Shown above is a schematic of the cochlea’s organ of Corti, named after the Italian anatomist Alfonse Corti, who originally described it in 1851. Its function is to transform the mechanical energy of sound waves into the electrochemical signals used by nerves via mechanosensory hair cells (G,C). Systematic variations in stiffness and size of the stereocilia arrayed atop each hair cell enable these specialized epithelial cells to respond to a range of sound frequencies. The signal is then transmitted to spinal ganglion neurons within the cochlear nerve (N) for processing in the auditory cortex. Hair cells are a popular subject of current studies, due to research into the mechanisms of their extremely sensitive transduction of mechanical stimuli. In addition, hair cells express many genetic mutations that underlie congenital deafness. Hair cell death is the primary cause of age-related hearing loss, prompting active research efforts to preserve or replace them. 

3D print by Jeremy Swan based on an original illustration by Santiago Ramon y Cajal. Courtesy of the Cajal Institute, Spanish National Research Council or CSIC©