Module 20: Hearing

loudness perception

based on the NUMBER of activated hair cells

auditory nerve

bundle of axons that transmits auditory information from hair cells to auditory cortex via the thalamus

middle ear

chamber between eardrum and cochlea where hammer/anvil/stirrup are located

oval window

cochlea's membrane; vibrates in response to sound waves

cochlea

coiled, bony, fluid-filled tube in inner ear

cochlear implant

device that allows people with sensorineural hearing loss to hear

sensorineural hearing loss

hearing loss caused by damage to cochlea's receptor cells or auditory nerves (inner ear) also called nerve deafness

conduction hearing loss

hearing loss caused by damage to mechanical system that conducts sound wave to cochlea (outer/middle ear)

amplitude

height of a wave; determines loudness

pitch

how high or low a tone is (long wave = low pitch)

inner ear

innermost part of ear; contains cochlea, semicircular canals, and vestibular sacs

frequency

number of complete wavelengths that pass a point in a given time (ex: per second); determines pitch

volley principle

part of frequency theory; principle that neurons alternate to produce a combined frequency high enough that we can hear high pitches

basilar membrane

part of inner ear lined with hair cells

audition

sense or act of hearing

hair cell

sensory receptor in inner ear that triggers nerve impulses when bent; responds to a certain frequency

sound localization

sound waves strike one ear SOONER and MORE INTENSELY than the other

frequency theory

theory that we hear different pitches based on how fast nerve impulses are traveling up auditory nerve explains HIGH pitch perception

eardrum

tight membrane that sound waves cause to vibrate

hammer, anvil, stirrup

tiny bones within middle ear that concentrate eardrum's vibrations onto cochlea's oval window

decibel

unit for measuring sound

outer ear

visible part of ear; channels sound waves toward middle ear

place theory

von Helmholtz's theory that we hear different pitches based on which part of basilar membrane is stimulated explains LOW pitch perception