SHS 311 TEST 2.
From question to perfection| Study with confidence!
Know the anatomical terms introduced in class, know where the part is located, and how it
is connected to the other parts. (e.g., what are the four parts of the peripheral auditory
system and what are the three Ossicles in the Middle Ear?) - Answer: - four parts of the
peripheral auditory system: outer ear, middle ear, inner ear, auditory nerve
- three ossicles in the middle ear: malleus, incus, stapes
Understand how standing wave is created in the Ear Canal and the resulted resonant
frequency. - Answer: when sound enters the outer ear canal a part of it will be reflected by
the tympanic membrane or ear drum; when the original sound wave and reflected sound
wave meet with each other at a certain frequency there will be a standing wave in the outer
ear canal; frequency of standing wave would be equal to some speed divided by 4 times
the length of the ear canal -> generally between 2000 and 4000 Hertz
What are the three ways the Middle Ear addresses the impedance mismatch between air
and the fluids and tissues of the Inner Ear? - Answer: 1) area difference between the
manubrium and the stapes footplates will cause the pressure at the footplate to be about
17 times higher than the pressure at the manubrium when the same force is applied to
both
2) lever action of the ossicular chain because the supporting point for this lever is more
close to the stapes footplate than to the manubrium so the force at the stapes footplate
would be 1.3 times higher or stronger than that at the manubrium
3) buckling effect - middle part of the tympanic membrane that is connected to the
manubrium moves the most and thus effectively increases the force at the manubrium by
about 2 times
How does the Eustachian Tube help sound transmission through the Middle ear? - Answer:
Eustachian tube helps to connect the middle ear cavity to the nasal cavity and to the outer
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, world so that the air pressures on both sides of the tympanic membrane are equal to each
other, this way the tympanic membrane can be in the resting state and be most sensitive to
the incoming sound
Why is the footplate of Stapes only connected to the Oval Window? - Answer: this is to
avoid the oval window and round window being stimulated in the same direction at the
same time, if that happens their movements will cancel each other out making the sound
transmission to the inner ear very ineffective
Know the anatomical terms introduced in class, know where the part is located, and how it
is connected to the other parts. (e.g., what are the three passages and the fluids in the
Cochlea, what are the different cells, membranes, and structures in the Organ of Corti?) -
Answer: Cochlea
- scala vestibuli and scale tympani are filled with perilymph
- scala media is filled with endolymph
-stria vascularis helps maintain the ionic composition of the cochlear fluid, which is vital to
the transduction of sound vibrations into neural signals
What is the traveling wave? - Answer: when a sound vibration reaches the cochlea it will
generate a cochlear wave that starts at the basal end and travels to the apical end along
the basilar membrane and that cochlear wave is called a traveling wave
How does the traveling wave change in terms of the location of maximal vibration as the
frequency of sound changes? - Answer: end connected to middle ear ossicles is the basal
end and the other would be apical; low frequency input would generate the maximum
vibration close to the apical end while a high frequency will generate the maximum
vibration close to the basal end
APPHIA – Crafted with Care and Precision for Academic Excellence. 2
From question to perfection| Study with confidence!
Know the anatomical terms introduced in class, know where the part is located, and how it
is connected to the other parts. (e.g., what are the four parts of the peripheral auditory
system and what are the three Ossicles in the Middle Ear?) - Answer: - four parts of the
peripheral auditory system: outer ear, middle ear, inner ear, auditory nerve
- three ossicles in the middle ear: malleus, incus, stapes
Understand how standing wave is created in the Ear Canal and the resulted resonant
frequency. - Answer: when sound enters the outer ear canal a part of it will be reflected by
the tympanic membrane or ear drum; when the original sound wave and reflected sound
wave meet with each other at a certain frequency there will be a standing wave in the outer
ear canal; frequency of standing wave would be equal to some speed divided by 4 times
the length of the ear canal -> generally between 2000 and 4000 Hertz
What are the three ways the Middle Ear addresses the impedance mismatch between air
and the fluids and tissues of the Inner Ear? - Answer: 1) area difference between the
manubrium and the stapes footplates will cause the pressure at the footplate to be about
17 times higher than the pressure at the manubrium when the same force is applied to
both
2) lever action of the ossicular chain because the supporting point for this lever is more
close to the stapes footplate than to the manubrium so the force at the stapes footplate
would be 1.3 times higher or stronger than that at the manubrium
3) buckling effect - middle part of the tympanic membrane that is connected to the
manubrium moves the most and thus effectively increases the force at the manubrium by
about 2 times
How does the Eustachian Tube help sound transmission through the Middle ear? - Answer:
Eustachian tube helps to connect the middle ear cavity to the nasal cavity and to the outer
APPHIA – Crafted with Care and Precision for Academic Excellence. 1
, world so that the air pressures on both sides of the tympanic membrane are equal to each
other, this way the tympanic membrane can be in the resting state and be most sensitive to
the incoming sound
Why is the footplate of Stapes only connected to the Oval Window? - Answer: this is to
avoid the oval window and round window being stimulated in the same direction at the
same time, if that happens their movements will cancel each other out making the sound
transmission to the inner ear very ineffective
Know the anatomical terms introduced in class, know where the part is located, and how it
is connected to the other parts. (e.g., what are the three passages and the fluids in the
Cochlea, what are the different cells, membranes, and structures in the Organ of Corti?) -
Answer: Cochlea
- scala vestibuli and scale tympani are filled with perilymph
- scala media is filled with endolymph
-stria vascularis helps maintain the ionic composition of the cochlear fluid, which is vital to
the transduction of sound vibrations into neural signals
What is the traveling wave? - Answer: when a sound vibration reaches the cochlea it will
generate a cochlear wave that starts at the basal end and travels to the apical end along
the basilar membrane and that cochlear wave is called a traveling wave
How does the traveling wave change in terms of the location of maximal vibration as the
frequency of sound changes? - Answer: end connected to middle ear ossicles is the basal
end and the other would be apical; low frequency input would generate the maximum
vibration close to the apical end while a high frequency will generate the maximum
vibration close to the basal end
APPHIA – Crafted with Care and Precision for Academic Excellence. 2
