Chapter 10: The Auditory System Flashcards
How is hearing different from vision?
Our vision only comes from what is in front of us, while sound comes to us from all 360 degrees
__________ is transforming information in the environment (sound pressure waves) into a perception that can be used to understand the world and guide action
Hearing
There must be a _________ , such as air or water, to
conduct sound. In the absence of this, as
in the near vacuum of space, sound cannot exist.
medium
The ________________ is the periodic variations in air pressure traveling out from the source of the variations
sound stimulus
– These periodic variations in pressure are the
sound wave.
– The source of the variations is the object making
the sound
5
6-10
pitch is
high note or low note
___________ is the number of cycles in a sound stimulus
that occur in 1 second
Frequency
As frequency gets larger, wavelength gets __________
shorter
By convention, wavelength is used when discussing
_______ and frequency is used when discussing _________
vision; sounds
Frequency is measured in _________, a unit of
measurement indicating the number of cycles per
second
hertz (Hz)
______ is the subjective experience of sound that is closely
associated with frequencies
Pitch
Lower frequencies are heard as lower in pitch; higher
frequencies are heard as higher in pitch
Frequency and Pitch/ T/F
True
12-15
pure tone
a sound wave in
which changes in air pressure
follow a sine wave pattern
Sound stimulus:
the periodic
variations in air pressure
traveling out from the source
of the variations
Sound waves:
the waves of pressure changes that occur in the air as a function of the vibration of a source
Cycle: in a sound wave, the
amount of time between one peak
of high pressure and the next
Amplitude: the difference
between maximum and
minimum sound pressures
Loudness: the perceptual
experience of the amplitude or
intensity of a sound stimulus
Loudness: the perceptual
experience of the amplitude or
intensity of a sound stimulus
Frequency (sound
stimulus): the number of
cycles that occur in a second
Pitch: the subjective
experience of sound that is
most closely associated with
the frequency of a sound
stimulus; related to the
experience of whether the
sound is high or low, such as
the two ends of the keyboard
of a piano
Hertz (Hz): a unit of measure
indicating the number of
cycles per second
Harmonics: higher frequencies
present in a complex sound
that are integer multiples of the
fundamental frequency (main
frequency)
Complex sound: a sound
consisting of a mix of
frequencies
Fourier analysis: a
mathematical procedure for
taking any complex waveform
and determining the simpler
waveforms that make up that
complex pattern; the simpler
waves used are sine waves
Fundamental frequency: the
lowest frequency in a complex
sound, which determines the
perceived pitch of that sound
Timbre: the perceived sound
differences between sounds
with the same pitch but
possessing different higher
harmonics
Phase: the position in one cycle
of a wave; there are 360 degrees
in a single cycle of a wave
Prolonged exposure above ___ decibels, can cause noise induced hearing loss.
85
Pinna: the structure that
collects sound and funnels it
into the auditory canal
External auditory canal
(external auditory meatus):
the channel that conducts
sound from the pinna to the
tympanic membrane
Tympanic membrane: a thin
elastic sheet that vibrates in
response to sounds coming
through the external auditory
canal; commonly known as the
eardrum
Ossicles: three small bones in
the middle ear
Malleus: the first ossicle
in the middle ear; receives
vibrations from the tympanic
membrane and transmits them
to the incus
Incus: an ossicle in the middle
ear; receives vibrations from
the malleus and transmits
them to the stapes
Stapes: an ossicle in the
middle ear; receives vibrations
from the incus and transmits
them to the oval window of the
inner ear
Stapes: an ossicle in the
middle ear; receives vibrations
from the incus and transmits
them to the oval window of the
inner ear
Tensor tympani: the muscle
that is attached to the malleus
Stapedius: the muscle that is
attached to the stapes
Acoustic reflex: a reflex that
tightens the tensor tympani
and the stapedius in response
to chronic loud noise
Acoustic reflex: a reflex that
tightens the tensor tympani
and the stapedius in response
to chronic loud noise
Tympanic canal: one of the
three chambers in the cochlea;
separated from the middle
canal by the basilar membrane
Middle canal (cochlear duct):
one of the three chambers in
the cochlea; separated from
the tympanic canal by the
basilar membrane; contains
the organ of Corti
Vestibular canal: one of the
three chambers in the cochlea;
separated from the middle
canal by Reissner’s membrane
Round window: a soft tissue
substance at the base of the
tympanic canal whose function
is as an “escape” valve for
excess pressure from loud
sounds that arrive in the cochlea
Reissner’s membrane: the
membrane that separates the
vestibular and middle canals
Basilar membrane:
the membrane that separates the tympanic canal from the middle
canal; the organ of Corti lies on the basilar membrane
the base of the system, pushing up the hair cells, when moved it will move differently depending on its thickness.
Organ of Corti: a structure
on the basilar membrane that
houses the hair cells that
transduce sound into a neural
signal
Perilymph: the fluid that fills
the tympanic canal and the
vestibular canal
Hair cells: cells that have
stereocilia for transducing
the movement of the basilar
membrane into a neural signal
Characteristic frequency:
the frequency to which any
particular location along the
basilar membrane responds best
Stereocilia: the hairlike parts
of the hair cells on the top of
the inner and outer hair cells
Outer hair cells: cells that
sharpen and amplify the
responses of the inner hair
cells
Inner hair cells: cells that are
responsible for transducing
the neural signal
Tectorial membrane:
a membrane that rests above the hair cells within the organ of Corti
provides what the hair can press up or rub against. It does not protect the hair cells because if its loud it can rub against too much on tectorial membrane which can cause damage.
Place code theory:
the view that different locations along the basilar membrane respond to different frequencies
basal membrane is thicker and more tightly wound at the base- vibrates for high frequencies
– Basal membrane is thinner and looser at apex- vibrates for lower frequencies.
– Allows the auditory system to discriminate among frequencies
Temporal code theory:
the view that frequency representation occurs because of a match between sound frequency and the firing rates of the auditory nerve
alternative view to place code theory
- More evidence for place code theory; esp w/ age-related hearing loss
OUTDATED
Otosclerosis:
an inherited bone disease in which the
ossicles, particularly the stapes, may calcify and therefore
be less conductive of sound
ossicle calcify, getting hardened
Tinnitus:
a condition in which people perceive sounds even when none are present
- Neural signal sent in the absence of a sound
- Associated with noise-induced hearing loss
- Can be a symptom of a number of disorders
Hearing aids:
electronic devices that amplify sound so that
people with hearing deficits can hear sounds that otherwise
would be below their thresholds
Convert sound signal into computer code
– Reconverted to analog sound for
wearer
– Can filter out extraneous noises
– Can tune into one specific frequency
Cochlear implants:
devices that are designed to restore
some hearing, typically of spoken voices, to deaf individuals;
they stimulate the auditory nerve artificially with an
electronic system, replacing the hair cells of the cochlea
– Stimulate the auditory nerve artificially with electronic system
– Essentially replace hair cells
– Mainly for language-related sounds
– Receiver converts sounds into electrical signal
– Travels by wire into the cochlea
– In the cochlea are electrodes
– When the electrodes are stimulated, it will induce a neural signal in auditory nerve fibers
What are parts of the outer ear anatomy?
Pinna (pi-nuh)
external auditory canal (meatus)
tympanic membrane
what are the parts of the middle ear anatamy?
ossicles
malleus
incus
stapes
22-33
Inner ear anatomy
Cochlea (kaa-clee-uh)
What is fluid filled?
Tectorial membrane is like the roof and the basilar membrane is the base. T/F
t
if the outer hair cells move, they fire. T/F
BM gets ______ flexible as we age
less
The area that is least flexible, the higher frequency range, gets even LESS flexible
* We lose the ability to hear these high frequencies as a result
* By the time we’re 50, we can’t hear above 12k Hz
presbycusis (Pres-by-cu-sis)
Loss of hearing associated with aging
– Basilar membrane gets stiffer as we age
* Harder for it to move based on sound
* Higher frequencies most affected
When hairs brush up against the tectorial membrane, this movement creates action potential. The action potential goes down the auditory nerve.
Conductive Hearing Loss
- Damage to some aspect of the sound transmission in outer or middle ear
- Sound doesn’t get to cochlea
– Blocked canal
– Damage to ossicles
– Torn tympanic membrane
Otosclerosis
– Inherited disease
– Ossicles calcify
* Cannot move in response to sound
Sensorineural Hearing Loss
- Hearing loss that occurs because of damage to the cochlea, auditory nerve, or primary auditory cortex
– Acquired or genetic
– Minor to profound
Inner hair cells in the cochlea form
___________ with the auditory nerve
fibers
synapses
The auditory nerve fibers bundle together to form _______________.
the 8th cranial nerve
Each auditory nerve fiber has a characteristic frequency that comes from a different part of the __________________. (two words)
basilar membrane
A whistle is so loud and shrill that it makes Sandra’s ear ache. The whistle has ____ amplitude and ________ frequency.
high amplitude, high frequency
A person who constantly hears a bell ringing probably suffers from tinnitus. T/F
True
The muscle that is attached to the malleus is called the ______.
tensor tympani
Amplitude is the difference between maximum and minimum sound pressures. T/F
True
Outer hair cells are responsible for transducing the neural signal, whereas inner hair cells refine and amplify the neural responses of the outer hair cells.
False, its the other way around
The external auditory canal conducts sound from the pinna to the basilar membrane.
False, its the tympanic membrane not basilar membrane
Which of the following instruments has the highest fundamental frequency?
piccolo
The part of the ear that sticks out of the side of a person’s head is called the ______.
pinna
The view that different locations along the basilar membrane respond to different frequencies is called the temporal code theory.
True
False
false
While analyzing the sound of a high C on the piano, Edgar realizes this complex sound has many frequencies by using the ______.
Fourier analysis
Cochlear implants are often placed in infants who are born congenitally deaf. T/F
true
Which of the following is separated from the cochlear duct by Reissner’s membrane?
the vestibular canal
The malleus vibrates and transmits sound to the stapes.
True
False
False
Which of the following consists of the fibers that separate the tympanic canal from the middle canal?
the basilar membrane
A soft tissue substance at the base of the tympanic canal whose function is as an “escape” valve for excess pressure from loud sounds that arrive in the cochlea is the ______.
round window
If Nancy blows a whistle that emits a sound with a frequency of 30,000 Hz at moderate loudness, which of the following would most likely happen?
Nancy’s dog would hear the sound.
Because of drugs she took for cancer treatment, Natasha suffers from hearing loss, which is most likely ______.
sensorineural hearing loss
Sanzhar is experiencing hearing loss because his stapes has calcified. He has a disease called ______.
osteosclerosis
A person can adjust hearing aids to amplify nearby sounds and block out other sounds.
True
False
true
Javier is pleased with the guitar he just bought because it has a rich sound. The quality that provides this sound is called ______.
timbre
