Cochlea

File:3DPX-002432 Cochlea and semicircular canals Nevit Dilmen.stl

Cochlea

File:Journey of Sound to the Brain.ogg

Gray920

Gray921

Cochlea is a spiral-shaped, fluid-filled inner ear structure; it is key to hearing in humans and other vertebrates. Its primary function is to convert sound vibrations from the outer ear into electrical signals that the brain can interpret as sound. This process involves various parts of the cochlea working in concert, including the scala tympani, scala vestibuli, and the cochlear duct.

Anatomy

The cochlea is a part of the inner ear located within the temporal bone of the skull. It is divided longitudinally by the basilar membrane, which separates two fluid-filled tubes that spiral around a central bony pillar called the modiolus. These tubes are known as the scala tympani and scala vestibuli, which are filled with perilymph fluid. The scala media, or cochlear duct, is filled with endolymph and is where the organ of Corti, the sensory organ of hearing, is located.

Function

Sound waves enter the cochlea via the oval window, causing the perilymph in the scala vestibuli to move. This movement is transferred to the cochlear duct, causing the basilar membrane to vibrate. These vibrations are detected by hair cells in the organ of Corti, which convert them into electrical signals. These signals are then transmitted to the brain via the auditory nerve, allowing for the perception of sound.

Clinical Significance

Damage to the cochlea or the nerve pathways from the cochlea to the brain can result in sensorineural hearing loss, which is often irreversible. Conditions such as age-related hearing loss, noise-induced hearing loss, and certain infections can affect cochlear function. Treatments for cochlear-related hearing loss include hearing aids and cochlear implants, the latter of which directly stimulate the auditory nerve, bypassing damaged parts of the ear.

See Also

• Inner ear
• Hearing
• Auditory system
• Sensorineural hearing loss