Auditory System Flashcards
Where are sound waves transformed into neural impulses?
Cochlea
What is the job of the middle ear?
Amplify sound
Depolarization
Stereocilia bending towards the kinocilium
What is the apex of the basilar membrane tuned for?
Low frequency sounds
What is loudness coded by?
Action potential frequency
Stages of the auditory pathway
Cochlear nucleus
Superior olive
Inferior colliculus
Medial geniculate nucleus
Where are inter-aural differences in timing and intensity of sound processed?
Superior olive oil
What kind of frequency is the base of the basilar membrane tuned for?
High frequency
What happens in unilateral lesions to the auditory pathway
Ability to localize sound in space is disrupted (not perception of sound)
What perceives and interprets sound?
Auditory cortex
How do we localize sound?
Compiled auditory information arriving at the auditory cortex
Timing difference between sound in ears
Sound reaches one ear a tenth of a millisecond before the other ear
Best for low frequency
Processed in medial olive
Intensity differences between ears for sound
More intense on one side because the head absorbs some of it
Best for high frequency
Most common hearing loss
Fluid in the middle ear space muffles sound
Leads to decreased mobility of tympanic membrane
Leads to less precise hearing
Conductive loss
Hearing loss due to otitis media (scar tissue from middle ear infections)
And otosclerosis (stapes bone restricted)
Sensorineural loss
Hearing loss due to actual damage or loss of hair cells in cochlea
Path of sound into ear and into an action potential in the auditory nerve
Sound wave
Outer ear
Middle ear
Inner ear
Vibration of basilar membrane
Bend hairs
Depolarize hair cells
Release neurotransmitter to auditory nerve terminals
