What does the basilar membrane (BM) separate?
the scala media and scala tympani
What ion's movement underlies hair cell depolarization?
What are otoacoustic emissions (OAEs)?
sounds created by active OHCs
The inner hair cells (IHCs) are attached to the _____.
basilar membrane (BM)
This is a Na+-rich fluid that fills the scala vestibuli and bathes the basal end of the hair cells.
What do patients with auditory neuropathy use for sound localization?
interaural level difference (ILD)
The basilar membrane (BM) vibrates best to low frequencies near ______.
the apex of the cochlea
This is a K+-rich fluid that fills the scala media and bathes the apical ends of the hair cells.
This is caused by the head forming an acoustic shadow between the 2 ears.
an interaural level difference (ILD)
When does the hair cell hyperpolarize?
when the stereocilia bundle is pushed towards the direction of the shortest stereocilia
What comprises the external ear?
pinna --> external auditory meatus --> tympanic membrane
Human hearing spans frequencies of ____ to ____ Hz with a peak sensitivity around _____.
20-20,000; peak = 3000
What comprises the middle ear?
What is the function of the medial olicocochlear neurons (MOCs)?
they're feedback control to change the cochlear sensitivity
The ____ of sound increases when the air is compressed more forcefully, resulting in increased density of air.
What is presbycusis?
a loss of high frequency hearing
Where are the inner and outer hair cells found?
in the organ of Corti
What causes vertical displacement of the basilar and tectorial membranes?
cochlear fluid waves
What is the function of the stria vascularis?
pump K+ into the endolymph --> create (+) potential inside the scala media (the endocochlear potential)
What is the cochlear amplifier?
the mechanical amplification of the displacement of the basilar membrane (BM) by the outer hair cells (OHCs)
_____ lesions rostral to the cochlear nuclei produce bilateral deafness.
Movements of the basilar membrane (BM) are translated by _____ into electrical signals.
inner hair cells (IHCs)
Movements of the basilar membrane (BM) are translated by inner hair cells (IHCs) into ______.
Are there more type I or type II ANFs?
From the inferior colliculus, fibers project mainly to the ____.
ipsilateral medial geniculate in the thalamus
_____ are innervated by efferent neurons called medial olicocochlear neurons (MOCs).
Outer hair cells (OHCs)
What comprises the inner ear?
- the cochlea
- the semicircular canals
Unilateral lesions in the inferior colliculus (IC) or more central cause ______ deafness.
What are auditory nerve fibers (ANFs)?
the 8th CN (spiral ganglion) innervating the inner and outer hair cells
What are the 2 primary qualities of sound?