Sense organs (eye and ear)
Cochlea
Cochlea
- Origin
- Spiral part of the bony labyrinth in the temporal bone, two and a half turns around the modiolus
- Insertion
- Connects to the vestibule through the scala vestibuli; the round window closes the scala tympani
- Function
- Converts perilymph vibration into nerve impulses in the organ of Corti, tonotopically ordered (high tones basal, low tones apical)
- Innervation
- Cochlear part of the vestibulocochlear nerve (VIII), spiral ganglion
- Movement & chain
- The basilar membrane vibrates at the place matching the frequency of the sound presented
- Palpation
- Rinne and Weber tuning fork tests, pure tone audiometry, otoacoustic emissions in newborn hearing screening
- Clinical
- Sensorineural hearing loss, presbyacusis, noise trauma with a 4 kHz dip, ototoxicity from aminoglycosides and cisplatin, Meniere disease
- Segmental innervation
- Cranial nerve VIII to the cochlear nuclei in the pons
- In clinical practice
- Cochlear implantation in severe sensorineural loss; hearing protection is the only real prevention of noise damage
- Region in the model
- Sense organs (eye and ear)