Organization David Keene

Tenth step

Ninth step

Eighth step

Seventh step

Sixth step

fifth step

Fourth step

Third step

Second Step

First step

Four orders of sensory neurons carry auditory to the temporal lobe (two stops in the pons, one in the midbrain and one in the thalamus)

Postsynaptic sensory neuron (branches of CN VIII) sends information to CNS

Stereocilia of hairs cell bends, K+ influx depolarizes the cell and it releases neurotransmitter

Basilar membrane vibrates

Endolymph in cochlear duct displaced (also perilymph of scala tympani displaced as waves exit the cochlea at round window)

Waves produced in perilymph of scala vestibuli

Sound waves reach oval window that vibrates

Sound waves travel through ossicles (malleus, incus, stapes)

Sound waves strike tympanic membrane

Sound waves amplified by outer ear

Solution

Organize each step of hearing

Review me first!

10

The process of hearing begins as sound waves are amplified by the outer ear and directed toward the tympanic membrane, causing it to vibrate. These vibrations travel through the ossicles—malleus, incus, and stapes—which further amplify the sound and transmit it to the oval window. The movement of the oval window generates waves in the perilymph of the scala vestibuli, leading to the displacement of endolymph in the cochlear duct and perilymph in the scala tympani as waves exit through the round window. This displacement causes the basilar membrane to vibrate, bending the stereocilia of hair cells. The bending opens K+ channels, resulting in depolarization and the release of neurotransmitters. The auditory signal is then transmitted via the postsynaptic sensory neurons of the vestibulocochlear nerve (CN VIII) to the central nervous system. Finally, four orders of sensory neurons carry the auditory information through the pons (two stops), midbrain, and thalamus before reaching the temporal lobe for processing.

Process of hearing

from auricle to brain