W22-L5: Hearing Flashcards
What is the function of the ossicles?
Matches the impedance of the air to impedance of the fluid within the inner ear
What are the three chambers of the cochlea?
Scala vestibuli
Scala media
Scala tympani
The basilar membrane is wider at the
Apex
The basilar membrane is stiffer at the
Base
The base responds to which frequencies?
High
What is the organ of corti?
Auditory receptors and hair cells sandwiched between basilar membrane and reticular lamina
Deflection of the hair bundle towards tallest stereocilium causes
opening of channels, and depolarization
Displacement of the hair bundle in either directions alters what?
membrane potential
T/F The change in membrane potential due to displacement is symmetric
False, Larger depolarizations than hyperpolarization
Why is potassium important in hearing?
Potassium serves to both depolarize and repolarize the cell
The endolymph has high or low potassium?
High
What are the two types of hair cells and where do they project to?
Inner hair cells:
95% of nerves that project
to brainstem nuclei
Outer hair cells:
Efferent inputs from the superior olivary complex
What can outer hair cells do during low intensity stimuli to amplify signal?
Change length, Depolarization causes cell contraction
Hyperpolarization causes cell elongation
How do antibiotics cause hearing loss?
Loss of outer hair cells, reduces basilar membrane movement
What is the auditory pathway to the cortex?
Cochlear nucleus, lateral lemniscus, inferior colliculus, MGN, cortex
