Audition Flashcards
3 parts of outer ear
- Pinna
- Ear canal
- Tympanic membrane
2 functions of pinna
- Selectively amplifies frequencies within speech range
2. Enhances sound localization ability
Tympanic membrane relays info to
Malleus
2 ossicles (out to in)
Malleus
Incus
Stapes
Middle ear compromise causes
Conductive hearing loss
Staples relays info to
Oval window
Reissner’s membrane separates
Cochlear duct from scala vestibuli
Basilar membrane separates
Cochlear duct from scala tympani
The organ of corti is covered by? floating in?
tectorial membrane
endolymph
What makes endolymph
stria vascularis
Main differences between IHC and OHC
- one row IHC, three rows of OHC
- 90% of fibers innervate IHCs
- 10 fibers innervate IHCs,
The tallest stereocilia is
Embedded in the tectorial membrane
2 functions of hair cells
- Mechano-electrical transduction
2. Neurotransmission
Which neurons are more sharply tuned?
Those with high best frequencies
What are cochlear cell tuning curves?
Reactivity of hair cells to their best frequency
Spontaneous ear noises are called
Thought to be caused by
Oto-acoustic emmissions
OHC electromotility: amplifies traveling wave in a positive feedback system. Cell length changes length in response to an electrical stimulus by a confomational change in motor protein in the lateral wall
What is the pattern of auditory nerve firing
- Brisk firing at onset of stimulus
- Plateaus with adaptation
- Transient drop out with termination of stimulus
2 ways neurons code signal
- Place code: fibers are in a tonotopic map relating to best frequency
- Frequency code: firing rate reflects stimulus frequency
Where does signals from both ears meet first?
Olivary nucleus
4 stops after olivary nucleus?
- Lateral lemiscus
- Inferior colliculus
- Medial geniculate nucleus
- Cortex
2 Functions of cochlear nucleus
- Switchboard sending auditory info
2. processing time and frequency info
What is the acoustic reflex
Tightening of stapedious muscle in response to loud noises
What forms the outer wall of the scala media
Stria vascularis
2 directions of hair cells and response
- Toward kinocilium: Depolarization
2. Away from kinocilium: hyperpolarization
3 subdivisions of Olivary Nucleus and functions
COINCIDENCE DETECTORS
MSO: sound localization using interaural delay cues
LSO: localization using intensity cues
Superior Olivary Complex: projects to inferior colliculus
What kind of map does the IC have
Spatio-topic map of auditory environment
