Anatomy and Physiology of Hearing Flashcards

Which structure in the inner ear is responsible for converting mechanical vibrations into electrical signals?

Answer: Organ of Corti

The Organ of Corti, located in the cochlea, contains hair cells that transduce mechanical vibrations into neural electrical signals.

The tonotopic organization of the cochlea means that:

Answer: Low frequencies are processed at the apex and high at the base

The cochlear base responds to high frequencies while the apex responds to low frequencies, a spatial arrangement called tonotopy.

What is the primary function of the Eustachian tube?

Answer: Equalize air pressure between the middle ear and nasopharynx

The Eustachian tube connects the middle ear to the nasopharynx, allowing pressure equalization on both sides of the tympanic membrane.

Which type of hair cells are most numerous in the cochlea and primarily responsible for amplification?

Answer: Outer hair cells

Outer hair cells (approximately 12,000) act as a cochlear amplifier by actively changing length, boosting sensitivity and frequency selectivity.

The scala vestibuli and scala tympani are filled with:

Answer: Perilymph

Perilymph, which resembles extracellular fluid in ionic composition, fills both the scala vestibuli and scala tympani.

Damage to which nerve is responsible for sensorineural hearing loss in acoustic neuroma?

Answer: Vestibulocochlear nerve (CN VIII)

Acoustic neuromas (vestibular schwannomas) grow on CN VIII, compressing it and causing progressive sensorineural hearing loss.

The helicotrema is located:

Answer: At the apex of the cochlea connecting the two scalae

The helicotrema is the small opening at the cochlear apex where the scala vestibuli and scala tympani communicate.