Auditory Anatomy and Physiology Flashcards
What nerve passes posterior to the pars flaccida of the tympanic membrane?
The chorda tympani, a branch of CN VII.
What is the canal that connects to middle ear to the oral pharynx?
The pharyngotympanic (eustachian) tube.
What muscles originate on the pharyngotympanic tube?
The levator veli palatini and the salpingopharyngeus.
What cranial nerve contributes parasympathetic fibers to the tympanic plexus overlying the promontory?
CN IX (glossopharyngeal). Gives off the tympanic nerve which forms the tympanic plexus which then gives off the lesser petrosal nerve.
What muscles attach to the middle ear ossicles?
The stapedius and the tensor tympani.
Which middle ear muscle is innervated by the facial nerve?
Stapedius (tensor tympani is by trigem).
What are the three middle ear ossicles?
The malleus, incus, and stapes (MIS).
What are the three compartments of the cochlea?
The scala vestibule (vestibular duct), the scala tympani (tympanic duct), and the scala media (cochlear duct).
What are the aqueous compartments of the cochlea?
The scala vestibule and scala tympani (filled with perilymph).
Which cochlear compartment contains endolymph?
The scala media.
What is the cochlear basilar membrane?
A stiff structural component of the inner ear that separates the scala tympani and scala media. The organ of corti rests upon it in the scala media.
What term is used to describe the deflection of the basilar membrane induced by sound waves?
Traveling wave.
What is the organ of corti comprised of?
Mechanosensory hair cells (inner and outer hair cells).
What cochlear hair cell activates afferent neurons?
The inner hair cells.
What hair cells serve as a cochlear amplifier?
The outer hair cells.
What protein in the outer hair cell wall contracts to generate distortion product otoacoustic emissions?
Prestin.
What is the cochlear hair cell irreversibly damaged by loud sounds?
Outer hair cells.
What ion channel is lost when the outer haor cell stereocilia is lost?
Cl- channels.
What is the ganglion that contains cell bodies for the cochlear nerve?
The spiral ganglion (cochlear ganglion).
What midbrain nuclei receive cochlear nerve afferents?
The inferior colliculus.
What are the brainstem nuclei that process cochlear output?
The ventral and dorsal cochlear nuclei.
What cochlear nucleus provides input to the superior olivary complex?
The ventral cochlear nucleus.
How does the lateral superior olivary nucleus localize sound?
It compares differences in sound intensity between the two ears.
How does the medial superior olivary nucleus localize sound?
It detects time lag between acoustic signals entering the two ears.
What does the vestibular (Reissner’s) membrane separate?
The scala vestibuli and the scala media.
Where are high frequency sounds transmitted in the basilar membrane?
At the base of the basilar membrane (where it is the thickest).
Where are low frequency sounds transmitted in the basilar membrane?
At the apex of the basilar membrane (where it’s most flexible).
What is the eponym for the transverse gyrus of the temporal lobe that hosts the primary auditory cortex?
Heschl’s gyrus.
