SHS 280: FINAL EXAM QUESTIONS
AND ANSWERS WITH FULL
SOLUTIONS, UPDATED 2026,
GRADED A+, SUCCESS
GUARANTEED
1. The Outer Ear
Structure: Consists of the Pinna (auricle) and the External Auditory Canal.
Function: The Pinna acts as a satellite dish, collecting and amplifying sound
waves. It provides critical localization cues, helping the brain determine if a
sound is coming from above, below, or behind.
Plasticity: The brain possesses neuroplasticity, allowing it to adapt to
changes in the way the pinna shapes sound (e.g., after surgery or wearing a
prosthetic).
2. The Middle Ear: The Impedance Matcher
The middle ear's primary job is to transfer energy from air (low density) to fluid
(high density) without losing signal strength.
The Mechanism: Three tiny bones (ossicles)—the Malleus, Incus, and
Stapes—transform Air Pressure into Mechanical Force.
The Loss: Without the middle ear mechanisms, there is an approximately 60
dB conductive loss, as most sound energy would simply bounce off the
fluid of the inner ear.
3. Protective Mechanisms: The Stapedial Reflex
The middle ear isn't just a passive conductor; it has a built-in "volume limiter"
controlled by neurons.
Acoustic Stapedial Reflex: The stapedial muscle contracts in response to
intense, long-duration sounds.
, Features:
o Bilateral: Stimulating one ear causes the reflex in both.
o Speed: It is not a fast reflex, meaning it does not protect against
sudden "impulse" noises like gunshots.
o Control: It is managed by Cranial Nerve VII (the Facial Nerve).
o Benefit: It can improve hearing in the presence of ongoing loud
background noise or internal "head noises."
4. The Inner Ear (The Cochlea)
The transition to the final stage of hearing occurs at the Oval Window.
Process: The movement of the stapes against the oval window pushes
against the fluid inside the cochlea.
Energy Chain: Air Pressure $\rightarrow$ Mechanical Force
$\rightarrow$ Fluid Motion.
Result: This fluid motion eventually bends microscopic hair cells, which
trigger the neural impulses sent to the brain.
The Cochlea -ANSWER✔✔A snail shell-shaped structure containing 2.5 turns in
humans. Fluid is non-compressible. Contains 3 compartments: scala vestibuli,
scala media, and scala tympani.
Scala Vestibuli -ANSWER✔✔Fluid in this structure is displaced by the movement
of the stapes against the oval window.
Scala Tympani -ANSWER✔✔Fluid travels to the apex (top of the shell) of the
cochlea and then travels back to the round window via this structure.
, Causes the basilar membrane to move -ANSWER✔✔The motion of the fluid in the
cochlea. . .
Lower resonance -ANSWER✔✔More massive things = ....
Basilar Membrane -ANSWER✔✔The first place in the auditory system where
there is tonotopic organization. This structure essentially decomposes complex
sounds into their component sine waves.
Tonotopic Organization -ANSWER✔✔Because different regions selectively move
for different frequencies, there is a __________________ (place theory).
Organ of Corti -ANSWER✔✔Sits on top of the basilar membrane. Contains the
hair cells (first neural component of the auditory system). Two types of hair cells:
inner and outer
Inner Hair Cells -ANSWER✔✔Responsible for sending the perception of sound to
the cortex. Allow you to hear. If lost, won't be able to hear at all.
Outer Hair Cells -ANSWER✔✔Receives signals from the cortex and modifies the
perception of sound. Affect how you hear/how the basilar membrane moves
(amplifies movement). If lost, won't be able to hear quieter noises.
Sensorineural Hearing Loss -ANSWER✔✔Often results from damage to the outer
hair cells.
AND ANSWERS WITH FULL
SOLUTIONS, UPDATED 2026,
GRADED A+, SUCCESS
GUARANTEED
1. The Outer Ear
Structure: Consists of the Pinna (auricle) and the External Auditory Canal.
Function: The Pinna acts as a satellite dish, collecting and amplifying sound
waves. It provides critical localization cues, helping the brain determine if a
sound is coming from above, below, or behind.
Plasticity: The brain possesses neuroplasticity, allowing it to adapt to
changes in the way the pinna shapes sound (e.g., after surgery or wearing a
prosthetic).
2. The Middle Ear: The Impedance Matcher
The middle ear's primary job is to transfer energy from air (low density) to fluid
(high density) without losing signal strength.
The Mechanism: Three tiny bones (ossicles)—the Malleus, Incus, and
Stapes—transform Air Pressure into Mechanical Force.
The Loss: Without the middle ear mechanisms, there is an approximately 60
dB conductive loss, as most sound energy would simply bounce off the
fluid of the inner ear.
3. Protective Mechanisms: The Stapedial Reflex
The middle ear isn't just a passive conductor; it has a built-in "volume limiter"
controlled by neurons.
Acoustic Stapedial Reflex: The stapedial muscle contracts in response to
intense, long-duration sounds.
, Features:
o Bilateral: Stimulating one ear causes the reflex in both.
o Speed: It is not a fast reflex, meaning it does not protect against
sudden "impulse" noises like gunshots.
o Control: It is managed by Cranial Nerve VII (the Facial Nerve).
o Benefit: It can improve hearing in the presence of ongoing loud
background noise or internal "head noises."
4. The Inner Ear (The Cochlea)
The transition to the final stage of hearing occurs at the Oval Window.
Process: The movement of the stapes against the oval window pushes
against the fluid inside the cochlea.
Energy Chain: Air Pressure $\rightarrow$ Mechanical Force
$\rightarrow$ Fluid Motion.
Result: This fluid motion eventually bends microscopic hair cells, which
trigger the neural impulses sent to the brain.
The Cochlea -ANSWER✔✔A snail shell-shaped structure containing 2.5 turns in
humans. Fluid is non-compressible. Contains 3 compartments: scala vestibuli,
scala media, and scala tympani.
Scala Vestibuli -ANSWER✔✔Fluid in this structure is displaced by the movement
of the stapes against the oval window.
Scala Tympani -ANSWER✔✔Fluid travels to the apex (top of the shell) of the
cochlea and then travels back to the round window via this structure.
, Causes the basilar membrane to move -ANSWER✔✔The motion of the fluid in the
cochlea. . .
Lower resonance -ANSWER✔✔More massive things = ....
Basilar Membrane -ANSWER✔✔The first place in the auditory system where
there is tonotopic organization. This structure essentially decomposes complex
sounds into their component sine waves.
Tonotopic Organization -ANSWER✔✔Because different regions selectively move
for different frequencies, there is a __________________ (place theory).
Organ of Corti -ANSWER✔✔Sits on top of the basilar membrane. Contains the
hair cells (first neural component of the auditory system). Two types of hair cells:
inner and outer
Inner Hair Cells -ANSWER✔✔Responsible for sending the perception of sound to
the cortex. Allow you to hear. If lost, won't be able to hear at all.
Outer Hair Cells -ANSWER✔✔Receives signals from the cortex and modifies the
perception of sound. Affect how you hear/how the basilar membrane moves
(amplifies movement). If lost, won't be able to hear quieter noises.
Sensorineural Hearing Loss -ANSWER✔✔Often results from damage to the outer
hair cells.
