PNB 2274 Exam 4 2025/2026 Exam
Questions and Detailed Answers | Get it
100% Correct Answers
By definition, what is hearing? - 🧠 ANSWER ✔✔The detection of sound;
mechanical deformation of air molecules
What is the make-up of sound waves? - 🧠 ANSWER ✔✔Sound waves
alternate between peaks in which air molecules are compressed and
valleys in the air molecules are less compressed.
Name the 4 ways in which sound is differentiated and their respective units:
- 🧠 ANSWER ✔✔- frequency (Hz): cycles per second
- pitch: perception of frequency
- intensity: energy, loudness
- Amplitude (Decibels): amplitude of sound waves measures intensity
List the structures of the external ear and the overall function of the
external ear: - 🧠 ANSWER ✔✔pinna and auricle
- directs sound energy into the auditory canal
1
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,List the structures of the middle ear: - 🧠 ANSWER ✔✔tympanic membrane
and ossicles (malleus, incus, stapes)
List the structures of the inner ear: - 🧠 ANSWER ✔✔cochlea, semicircular
canals, vestibular apparatus, oval and round windows
What is the mechanism of sound transduction? - 🧠 ANSWER ✔✔Pressure
waves at the tympanic membrane result in movement of the ossicles;
ossicles focus vibrations onto a much smaller oval window (19:1)
What is acoustic impedance and what structure is responsible for
overcoming it? - 🧠 ANSWER ✔✔The opposition to passage of sound
waves; ossicles overcome impedance of the inner ear
What is the function of the tympanic membrane; what is tympanic reflex? -
🧠 ANSWER ✔✔- ossicles focus vibrations of tympanic membrane onto oval
window
- Tympanic reflex: tensor tympani and stapedius muscles contract; this
dampens (reduces) tympanic membrane vibrations, moves position off
ossicles; is meant to protect against loud sounds however the reaction time
is too slow to protect against gunshots
2
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,Explain the the ear's protective mechanism? - 🧠 ANSWER ✔✔Muscle
tension tightens the tympanic membrane and alters the position of the
ossicles to reduce response to loud sounds
Where in the inner ear can you find perilymph?
Where in the inner ear can you find endolymph? - 🧠 ANSWER
✔✔Perilymph: between bony and membranous labyrinth
Endolymph: within the membranous labyrinth
Explain the structure of the cochlea: - 🧠 ANSWER ✔✔long coiled tube
divided into 3 channels by 2 thin membranes
- top tube: scala vestibuli; connected to oval window
- middle tube: scala media; contains the organ of corti
- bottom tube: scala tympani; connect to the round window
What are the important features of the organ of corti?
- what type of receptors? - 🧠 ANSWER ✔✔- hair cells and tectorial
membrane
- inner and outer hair cells which are mechanoreceptors
- cochlear nerve
3
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
, Explain the mechanism of the cochlear hair cells which leads to
depolarization or hyperpolarization? - 🧠 ANSWER ✔✔Standing waves
cause vibration of the basilar membrane; leads to movement of the
stereocilia on the apical surface of hair cells and gating of K+ channels
- stereocilia are graduated in size; if they bend toward the tallest it results in
depolarization but if they bend toward away it results in hyperpolarization
What are shear forces in reference to cochlear hair cells? - 🧠 ANSWER
✔✔- mechanical shear forces open K+ channels
- a graded potential (not an action potential) results
- when the stereocilia bend toward the tallest, tip links pope more channels
open and K+ influx depolarizes the cell; increased sensory neuron firing
- when cilia ben away from the tallest, tip links relet and ion channels close
leading to cell hyperpolarization and sensor neuron firing decreases
What are the characteristics of perilymph?
What are the characteristics of endolymph? - 🧠 ANSWER ✔✔Perilymph:
extracellular fluid located with scala tympani and scala vestibuli;
comparable to plasma and CSF because Na+ is the primary cation
4
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
Questions and Detailed Answers | Get it
100% Correct Answers
By definition, what is hearing? - 🧠 ANSWER ✔✔The detection of sound;
mechanical deformation of air molecules
What is the make-up of sound waves? - 🧠 ANSWER ✔✔Sound waves
alternate between peaks in which air molecules are compressed and
valleys in the air molecules are less compressed.
Name the 4 ways in which sound is differentiated and their respective units:
- 🧠 ANSWER ✔✔- frequency (Hz): cycles per second
- pitch: perception of frequency
- intensity: energy, loudness
- Amplitude (Decibels): amplitude of sound waves measures intensity
List the structures of the external ear and the overall function of the
external ear: - 🧠 ANSWER ✔✔pinna and auricle
- directs sound energy into the auditory canal
1
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,List the structures of the middle ear: - 🧠 ANSWER ✔✔tympanic membrane
and ossicles (malleus, incus, stapes)
List the structures of the inner ear: - 🧠 ANSWER ✔✔cochlea, semicircular
canals, vestibular apparatus, oval and round windows
What is the mechanism of sound transduction? - 🧠 ANSWER ✔✔Pressure
waves at the tympanic membrane result in movement of the ossicles;
ossicles focus vibrations onto a much smaller oval window (19:1)
What is acoustic impedance and what structure is responsible for
overcoming it? - 🧠 ANSWER ✔✔The opposition to passage of sound
waves; ossicles overcome impedance of the inner ear
What is the function of the tympanic membrane; what is tympanic reflex? -
🧠 ANSWER ✔✔- ossicles focus vibrations of tympanic membrane onto oval
window
- Tympanic reflex: tensor tympani and stapedius muscles contract; this
dampens (reduces) tympanic membrane vibrations, moves position off
ossicles; is meant to protect against loud sounds however the reaction time
is too slow to protect against gunshots
2
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,Explain the the ear's protective mechanism? - 🧠 ANSWER ✔✔Muscle
tension tightens the tympanic membrane and alters the position of the
ossicles to reduce response to loud sounds
Where in the inner ear can you find perilymph?
Where in the inner ear can you find endolymph? - 🧠 ANSWER
✔✔Perilymph: between bony and membranous labyrinth
Endolymph: within the membranous labyrinth
Explain the structure of the cochlea: - 🧠 ANSWER ✔✔long coiled tube
divided into 3 channels by 2 thin membranes
- top tube: scala vestibuli; connected to oval window
- middle tube: scala media; contains the organ of corti
- bottom tube: scala tympani; connect to the round window
What are the important features of the organ of corti?
- what type of receptors? - 🧠 ANSWER ✔✔- hair cells and tectorial
membrane
- inner and outer hair cells which are mechanoreceptors
- cochlear nerve
3
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
, Explain the mechanism of the cochlear hair cells which leads to
depolarization or hyperpolarization? - 🧠 ANSWER ✔✔Standing waves
cause vibration of the basilar membrane; leads to movement of the
stereocilia on the apical surface of hair cells and gating of K+ channels
- stereocilia are graduated in size; if they bend toward the tallest it results in
depolarization but if they bend toward away it results in hyperpolarization
What are shear forces in reference to cochlear hair cells? - 🧠 ANSWER
✔✔- mechanical shear forces open K+ channels
- a graded potential (not an action potential) results
- when the stereocilia bend toward the tallest, tip links pope more channels
open and K+ influx depolarizes the cell; increased sensory neuron firing
- when cilia ben away from the tallest, tip links relet and ion channels close
leading to cell hyperpolarization and sensor neuron firing decreases
What are the characteristics of perilymph?
What are the characteristics of endolymph? - 🧠 ANSWER ✔✔Perilymph:
extracellular fluid located with scala tympani and scala vestibuli;
comparable to plasma and CSF because Na+ is the primary cation
4
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
