<P> The organ of Corti, or spiral organ, is the receptor organ for hearing and is located in the mammalian cochlea . This highly varied strip of epithelial cells allows for transduction of auditory signals into nerve impulses' action potential . Transduction occurs through vibrations of structures in the inner ear causing displacement of cochlear fluid and movement of hair cells at the organ of Corti to produce electrochemical signals . </P> <P> Italian anatomist Alfonso Giacomo Gaspare Corti (1822--1876) discovered the organ of Corti in 1851 . The structure evolved from the basilar papilla and is crucial for mechanotransduction in mammals . </P> <P> The organ of Corti is located in the scala media of the cochlea of the inner ear between the vestibular duct and the tympanic duct and is composed of mechanosensory cells, known as hair cells . Strategically positioned on the basilar membrane of the organ of Corti are three rows of outer hair cells (OHCs) and one row of inner hair cells (IHCs). Separating these hair cells are supporting cells: Deiters cells, also called phalangeal cells, which separate and support both the OHCs and the IHCs . </P> <P> Projecting from the tops of the hair cells are tiny finger like projections called stereocilia, which are arranged in a graduated fashion with the shortest stereocilia on the outer rows and the longest in the center . This gradation is thought to be the most important anatomic feature of the organ of Corti because this allows the sensory cells superior tuning capability . </P>

Where are the basilar membrane and the organ of corti located