Ear Lecture

Which statement describes the principal function of the middle ear?

Transfer vibration from the tympanic membrane to iner-ear fluid

Which feature of the canine and feline external canal limits a direct view of the tympanic membrane?

the vertical portion turns into a horizontal portion

Which combination correctly describes the normal external ear canal?

Keratinized stratified squamous epithelium with outward epithelial migration

Which sequence traces vibration from the tympanic membrane to the oval window?

Malleus → Incus → Stapes

How does the middle ear help transfer sound enrgy from air into cochlear fluid?

By opening a larger tympanic area to a smaller stapes folotplate and using ossicular leverage

Which structure connects the tympanic cavity with the nasopharynx and supports pressure equalization?

Auditory tube

Which pairing of cochlear compartment and fluid is correct?

Scala media - endolymph

The organ of Corti rests on which structure?

Basilar membrane

During excitatory hair-bundle deflection, which event directly contributes to hair-cell depolarization?

K+ enters the hair cell from endolymph through mechanotransduction channels

Which statement correctly compares inner and outer cochlear hair cells?

Inner cells supply most auditory afferent input; outer cells amplify motion and sharpen tuning

A high-frequency sound produces its greatest traveling-wave response near which region?

The narrower, stiffer cochlear base

Which structure detects angular acceleration during changes in head rotation?

Crista and cupula in a semicircular duct ampulla

What is the role of otoconia in the utricle and saccule?

Add mass to the otolithic membrane so gravity and acceleration produce shear at hair bundlesA

A dog has tympanic bulla fluid but functional cochlear hair cells and auditory nerve. Which deficit is most directly expected?

Conductive loss from impaired mechanical sound trnasferA

A dog responds to sound, but unilateral deafness is suspected. Which test can assess an evoke auditory response from each ear separately?

Brainstem auditory evoked response testing (BAER)