Hearing and Balance: Ear Anatomy, Function - Anatomy and Physiology
- Which structure in the cochlear duct contains the auditory hair cells?
- The spiral organ (organ of Corti), which rests on the basilar membrane.
- Which two middle ear muscles contract to dampen ossicle vibration during very loud sounds?
- The tensor tympani and the stapedius.
- How does the middle ear increase the pressure of sound waves delivered to the inner ear?
- The tympanic membrane is much larger than the oval window, so force collected over a large area is concentrated onto a small one; ossicle leverage adds a little more.
- Which region of the basilar membrane responds best to high-frequency sounds?
- The base, near the oval window, where the membrane is narrow and stiff; the wide, flexible apex responds to low frequencies.
- What do the utricle and saccule detect?
- Linear acceleration and static head position relative to gravity, using otoliths on their maculae.
- What are the three auditory ossicles, in order from the tympanic membrane?
- Malleus, incus, and stapes.
- What type of hearing loss results from damage to the cochlear hair cells or the cochlear nerve?
- Sensorineural hearing loss.
- What type of head movement do the semicircular canals detect?
- Rotational (angular) acceleration of the head.
- Into which opening of the inner ear does the footplate of the stapes fit?
- The oval window.
- A Weber test lateralizes to the left ear, and the left Rinne test shows bone conduction louder than air conduction. What type of hearing loss is present?
- Left conductive hearing loss, caused by a problem in the outer or middle ear.
- Which ion, highly concentrated in endolymph, enters hair cells to depolarize them?
- Potassium (K+), which flows in through mechanically gated channels when the stereocilia bend.
- What is the function of the pharyngotympanic (auditory) tube?
- It connects the middle ear to the nasopharynx and equalizes middle ear pressure with atmospheric pressure.