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