Hearing & Cochlear Flashcards
What is the compression of a sound wave
height of the wave
What is the function of the pinna
localise sound in the vertical plane
Where is the tympanic membrane
end of the outer ear
What are the three bones/ossicles in the middle ear
malleus, incus, stapes
What are the parts of the inner ear
Vestibule area, cochlear, semicircular canal
Which connection in the middle ear is rigid
malleus to incus
Which connection in the middle ear is flexible
incus to stapes
What is the function of the middle ear ossicles
amplify sound
Where is endolymph present
inner ear - cochlear and vestibular system
Describe the properties of endolymph
high potassium concentration, high positive potential
Where is the tectorial membrane attached
inner part of cochlear
What are inner hair cells connected to
primary afferents
What are outer hair cells capable of
sensory transduction
What are the three fluid filled compartments of the middle ear
Scala vestibular, scala tympani, scala media
Which part of the basilar membrane reacts more to high frequency sounds
base
What sit on the basilar membrane
hair cells
What is the effect of the stapes moving outwards
ions move in, hair cell depolarises
What are stereo cillia
modified microvilli
Where are stereo cilia present
hair cells
What connects stereo cilium rows
tip links
What happens if the hair cells pull the tip link
mechano-electrical transducer channel opens
What liquid has a lower potassium content - endolymph or perilymph
perilymph
What can glutamate bind to
NMDA, AMPA, kainate
What happens when calcium moves into hair cells
fusion, release of neurotransmitter
What is the neurotransmitter in hair cells
glutamate
What is the function of outer hair cells
amplify movement of basilar membrane, increase stimulation of IHCs
Why does the middle ear have to amplify sound
overcome increased impedance of fluid within cochlear
What does the organ of corti contain
hair cells
What does the mechanical energy of sound cause
displacement of basilar membrane
How is the cochlear organised
tonotopically
