Hearing Flashcards
frequency
the number of pressure changes per cycle (measured in hertz)
sound wave
the physical stimulus for audition (created when objects vibrate thus moving air particles)
pitch
our perception of frequency (how high or low a note is)
amplitude
amount of change in pressure (intensity) (measured in decibels)
complexity
the number of different frequencies in a sound (music is very complex)
fundamental
lowest frequency, determines the pitch
harmonics
higher pitched tones related to the fundamental (we like singers voices because of their harmonics)
Fourier analysis of hearing
any complex tone can be represented as a series of simple tones (sine waves)
Ohm’s law
our brains do not process phase information for slowly varying sounds, but does respond to changes in amplitude and frequency
Resonant frequency
the frequency with which an object vibrates when hit by sound waves (an object will begin to vibrate if a sound wave matching the object’s resonant frequency travels close to the object)
pinna
the outer part of the ear/the part we see
external auditory canal
the tunnel going down towards the ear drum
tympanic membrane
the ear drum, thin layer of skin that vibrates when hit by sound waves
the outer ear includes…
the pinna, the external auditory canal, and the tympanic membrane
ossicles of the ear
malleus, incus and stapes
oval window
where the stapes meets the opening of the cochlea
Eustachian tube
from the middle ear down to the throat, serves as a protector, equalizes pressure on both sides of the ear drum (why our ears pop in the mountains)
the middle ear includes…
the ossicles (malleus, incus, and stapes, the Eustachian tube, the oval window
the inner ear includes…
cochlea, hair cells
impedance problem
the middle ear is filled with air and the inner ear is filled with fluid, the problem is that the sound has to all of a sudden change media through which it is traveling
parts of the cochlea as if looking at it in a circle head on
vestibular canal, reissner’s membrane, middle canal, basilar membrane, tympanic canal
hair cells
transducer mechanical movement in the cochlea into neural activity (about 3500)
outer hair cells
sharpen info sent by the inner hair cells, amplify sounds, otoacoustic emissions
inner hair cells
send information to the bran
place theory
patter of movement of the basilar membrane codes the frequency of a sound (where the wave is on the membrane tells what the frequency of a sound is), intensity is coded by the number of hair cells firing, we can’t always see this nice and crisp
temporal theory
frequency of a sound is coded by how many times auditory neurons fire (neurons fire 250 times for a 250hz sound)
phase locking
firing of a single neuron at one distinct point in the cycle of a sound wave, problem: nerve cells can only fire up to 1000hz
volley principle
the solution to the problem with temporal theory, cells work together in groups to code frequency, looks at the total output of a group of cells to determine frequency of a sound
tinnitus
continuous sound heard in the ears, yet no sound is actually present (running in the ears, normal hearing people can experience this)
exposure to noise
most common cause of hearing loss, hair cells are banging down so much they eventually cannot standup straight anymore therefore they don’t hit the other correctly when supposed to=that cell doesn’t fire
auditory adaption
a continuous tone begins to sound quieter over time therefore we feel as if we need to turn it up in order for it to be at an appropriate volume/amplitude/intensity
presbycusis
age related hearing loss, most loss is noticed among high frequencies
