This video follows the path of the sound waves traveling through each part of the ear (outer ear, middle ear, and inner ear), interacting with the tympanic membrane, auditory ossicles, and the bony labyrinth of the cochlea, until it arrives to the hair cells (auditory receptors), located further within the cochlea, that generate nerve impulses in response.
-Sound waves enter the ear, passing along the external auditory canal (meatus) to the tympanic membrane (eardrum). The membrane vibrates in response to sound. Low pitch sounds produce low vibration frequencies. Low volume sounds produce low vibration amplitudes. High frequency sounds produce faster vibrations of higher pitch.
-The tympanic membrane articulates with the auditory ossicles (three smallest bones in the body, the malleus, incus and stapes). They pass vibrations that initially hit the tympanic membrane to the oval window of the bony labyrinth in the cochlea displacing a fluid called perilymph. The round window at the end of the bony labyrinth facilitates this displacement by allowing the perilymph movement.
-The auditory vibrations move in the cochlea (snail-shaped) ascending via the scala vestibuli (scala means stairs) and descending via the scala tympani. Between these two is the cochlear duct, which is filled with endolymph, it is separated from the scala vestibuli by the Reissner’s (vestibular) membrane and from the scala tympani by the basilar membrane. The vibrations ascending the scala vestibuli are transferred to the Reissner’s membrane and the cochlear duct. Here, the hair cells in the organ of Corti, between the basilar membrane and tectorial membrane, receive the vibrations and generate nerve impluses. These impulses are sent to the brain via the cochlear nerve.
Video Produced by:
Brandon Pletsch. "Auditory Transduction (2002)." KZfaq. Brandon Pletsch, Aug 26, 2009.
Music by:
"Beethoven: Symphony No. 9 in D Minor, Op. 125 - "Choral": II. Molto Vivace" by Orchestre Révolutionnaire et Romantique & John Eliot Gardiner
Video Edited by:
V. Kolchenko & Tristan Charran, New York City College of Technology, 2017.