Module 20:Hearing

Disease

________ can cause sensorineural hearing loss, but usually the culprits are biological changes linked with heredity, aging, and prolonged exposer to ear- splitting noise or music.

Cochlear implants

________ can restore hearing for some people.

neural messages

Rippling of the basilar membrane, caused by pressure changes in the cochlear fluid, causes movement of the tiny hair cells, triggering ________ to be sent, via thalamus, to the auditory cortex in the brain.

sound waves

Through a mechanical chain of events, ________ traveling through the auditory canal cause tiny vibrations in the eardrum.

Audition

the sense or act of hearing.

visible portion

The outer ear is the ________ of the ear.

Frequency

the number of complete wavelengths that pass a point in a given time.

Stimulus Input

The ________: Sound Waves.

hair cell

If a(n) ________ loses sensitivity to soft sounds, it may still respond to soft sounds.

Cochlea

a coiled, bony, fluid- filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses.

Long waves

have low frequency- and low pitch.

Short waves

have high frequency- and high pitch.

Pitch

a tones experienced highness or lowness; depends on frequency.

Sensorineural hearing loss

________: hearing loss caused by damage to the cochleas hair receptor cells or to the auditory nerve; also called nerve deafness.

Cochlear implants

________: a device for converting sounds into electrical signals and stimulation the auditory nerve through electrodes threaded in to the cochlea.

Sound waves

are bands of compressed and expanded air.

20-1

What are the characteristics of air pressure waves that we hear as sound, and how does the ear transform sound energy into neural messages

audition

the sense or act of hearing

The Stimulus Input

Sound Waves

frequency

the number of complete wavelengths that pass a point in a given time

pitch

a tones experienced highness or lowness; depends on frequency

Long waves have low frequency

and low pitch

Short waves have high frequency

and high pitch

middle ear

the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochleas oval window

cochlea

a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses

inner ear

the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs

sensorineural hearing loss

hearing loss caused by damage to the cochleas hair receptor cells or to the auditory nerve; also called nerve deafness

conduction hearing loss

hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea

cochlear implants

a device for converting sounds into electrical signals and stimulation the auditory nerve through electrodes threaded in to the cochlea

20-2

What theories help us understand pitch perception

frequency theory

in hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch

place theory

proposes our brain interprets a particular pitch by decoding the place where a sound wave stimulates the cochleas basilar membrane

20-3

How do we locate sounds