Advanced Cochlea Quiz

Q1. How does movement of the stapes initiate fluid motion within the cochlea?

• The stapes pumps endolymph through the auditory tube
• The stapes moves the oval window and displaces perilymph in the scala vestibuli
• The stapes moves the round window before the oval window
• The stapes directly bends cochlear nerve axons

Q2. Why is the round window important for cochlear mechanics?

• It permits pressure displacement when the stapes moves cochlear fluid
• It anchors the ossicular chain to the tympanic membrane
• It separates the cochlea from the internal acoustic meatus
• It produces action potentials in spiral ganglion neurons

Q3. What mechanical event directly contributes to bending of hair-cell stereocilia in the organ of Corti?

• Rotation of the entire temporal bone
• Contraction of the tensor tympani inside the cochlear duct
• Movement of the tympanic membrane against the modiolus
• Relative shearing motion within the cochlear partition

Q4. Why is the high potassium concentration of endolymph important for auditory transduction?

• It prevents all ion movement across hair cells
• It supports potassium entry that depolarizes stimulated hair cells
• It converts hair cells into motor neurons
• It directly contracts the auditory ossicles

Q5. Why can damage to outer hair cells reduce hearing sensitivity even if many inner hair cells remain intact?

• Their loss prevents the stapes from moving
• Outer hair cells form the auditory nerve itself
• Loss of cochlear amplification weakens and broadens mechanical responses
• Outer hair cells are the only cells containing endolymph

Q6. Why can a lesion of the spiral ganglion cause sensorineural hearing loss?

• It interrupts primary auditory afferent transmission from hair cells
• It perforates the tympanic membrane
• It fixes the stapes at the oval window
• It blocks the pharyngotympanic tube

Q7. Why does the basilar membrane support frequency discrimination?

• Every frequency maximally displaces the entire membrane equally
• Its mechanical properties vary along the cochlear length to create tonotopy
• It contains separate ossicles for each frequency
• Its only function is to separate the middle and external ears

Q8. Why can disruption of the stria vascularis impair hearing?

• It disturbs the ionic and electrical environment needed by hair cells
• It blocks facial nerve motor output
• It removes the malleus from the ossicular chain
• It prevents the tympanic membrane from vibrating

Q9. Which anatomical feature allows scala vestibuli pressure waves to communicate with scala tympani at very low frequencies?

• Cochlear aqueduct only
• Helicotrema
• Internal acoustic meatus
• Facial hiatus

Q10. Which statement best integrates the anatomy and function of the cochlea?

• It detects angular acceleration through semicircular cristae
• It is a middle-ear chamber that mechanically opens the auditory tube
• It converts tonotopically organized mechanical vibrations into auditory neural signals
• It is an external-ear structure that collects sound before it reaches the tympanic membrane