Metz - Phys of Hearing Flashcards
hair cells are __________ with __________
mechanoreceptors ; stereovili
4 components of hearing
- Collection (of sound waves)
- Movement (of tymp. membrane)
- Vibration (of ossicles)
- Movement (of basilar membrane in cochlea)
the tympanic membrane movement facilitates the vibration of the
ossicles
the stapes is connected to the cochlea via the
oval window
the movement of the basilar membrane stimulates
hair cells
once the basilar membrane stimulates the hair cells, what is produced?
an electrical signal that is transmitted to the nervous system
high pressure
compressions
low pressure
rarefactions
how is the wavelength measured
the distance from the peak of one compression to the peak of the next compression
a longer wavelength would produce a ______ frequency of sound
low
the amplitude of a sound wave is indicative of the
intensity of the sound (how loud it is)
frequency is measured in
hertz
intensity of sound is expressed in
decibels
tall amplitude = what kind of sound
loud
short amplitude = what kind of sound
quiet
sustained sounds over ___ db can be damaging to hearing
70
the eardrum moves IN with the _______ portions of the sound waves
compression (high pressure)
the eardrum moves OUT with the _______ phases of the sound waves
rarefaction (low pressure)
the ossicles act as levers which help to
amplify sound
the ossicles connect the __________ to the oval window of the ________
tympanic membrane ; cochlea
amplification also occurs because the surface area of the tympanic membrane is much _______ than that of the oval window
greater
the amplification done by the ossicles is important because the movement of sound waves from the ambient air to the liquid internal environment would cause
significant dampening
At the oval window, the stapes vibrates and pushes and pulls the fluid in the __________
scala vestibuli
Sounds waves are dissipated at the end of the scala tympani in the ____________
round window
Sandwiched between the scala vestibuli and scala tympani is the __________
cochlear duct
endolymph is very high in ________ and low in _________
K+ ; Na+
what are the sensory receptors for hearing? where are they?
hair cells (in the basilar membrane of the cochlear duct)
the scala vestibuli and scala tympani are filled with perilymph which has what concentration
Na+ & Cl-
the tallest sterevolli is called the
kinocilium
the kinocilium interacts with the
tectorial membrane
At the base of the cochlea, the basilar membrane is _______ and _______
narrow and stiff
the base of the cochlea is only stimulated by __________ (ranging up to a frequency of around ______ Hertz)
high-pitched sounds
20,000
The apex of the cochlea is ______ and more ________
wider ; flexible
the end of the basilar membrane (apex) would detect __________ (around how many hertz?)
low-pitched sounds
20 hertz
what are the 5 sensory structures the vestibular system consists of
utricle
saccule
3 semicircular canals
the body moving forwards, backwards, or side-to-side is what kind of acceleration
horizontal
what detects rotational movement of the head
semicircular canals
hair cells in the utricle are embedded in the
macula
hair cells in the utricle are embedded where ? how is this different compared to where the hair cells in the cochlea are embedded?
utricle = embedded in macula
cochlea = embedded in basilar membrane
in hearing, hair bundles interact with a
tectorial membrane
in the otolithic organs, the stereovilli project into a gelatinous
otolithic membrane
the gelatinous otolithic membrane consists of mucopolysaccharides studded with _______ of _________ called __________
crystals ; calcium carbonate ; otoliths
otoliths give the otolithic membrane a ______ density than the surrounding _________
higher ; endolymph
as the head is moved, the inertia of the otolithic membrane _______ the stereovilli
deflects
what is another name for the sensory epithelium in the utricle
macula
mechanical deformation TOWARDS kinocilium _____ non-selective cation channels on tips of stereovilli
opens
mechanical deformation AWAY FROM kinocilium _____ non-selective cation channels on tips of stereovilli
closes
the opening of non-selective cation channels in the tips of the stereovilli allow small cations to flow _____ their electrochemical gradients
down
the opening of the channels allows an ______ of potassium into the hair cells of the utricle
influx
an influx of potassium into the hair cells of the utricle facilitates a ________ of the hair cell which ______ voltage gated Calcium channels
depolarization ; opens
when the stereovili have been bent away from the kinocilium, the non-selective cation channels ______
close
what happens to potassium when the non-selective cation channels in the utricle close? what happens to the hair cell?
Potassium is retained outside the cell and the hair cell hyperpolarizes
the hair cells in the semicircular canals are located in the bulge in sensory epithelium called the ?
ampulla
the hair cells in the ampulla project into a gelatinous material called the
cupula
the cupula does NOT contain
otoliths
the cupula has a density that is _______ to endolymph
similar
the function of the cupola is best compared to the
sail on a sailboat
with a sudden rotation of the semicircular canal, the endolymph ____________ due to _________
stays behind ; inertia
sudden rotation of the semicircular canal = the endolymph stays behind (unmoving) –> this exerts a force on the moveable _______
cupula (think wind on a sail)
Regarding the basilar membrane, action potentials are generated in the
cochlear nerve
regarding auditory transduction, the mechanical stimulation of the stereovilli is converted to electrical signals in the
cochlear nerve
In the basilar membrane, Glutamate sends signals via the __________ via action potentials
cochlear nerve
In the utricle, glutamate is released and binds to receptors. This initiates an increase in the frequency of action potentials in the
vestibular nerve
in the semicircular canals, the “force” bows the cupula which moves the hair cells and initiates effects on the generation of action potentials in the
vestibular nerve
the existence of an inner ear on the right and left sides of the body allow for ______ and ______ of additional inputs
comparison ; integration
different orientation of kinocilium allow for what in the center of the utricle, saccule, and semicircular canals
reversal line