auditory Flashcards
what range do we hear?
20-20,000 Hz
what does wavelength refer to?
pitch
what does amplitude refer to?
loudness
what does waveform refer to?
tone / timbre
where is the pinna & what does the pinna of the ear do?
pinna: outer ear
changes frequencies, learn between sound behind vs infront of us
cochlea
(feature and why)
fluid filled, allowing for a high impedence of sound (compared to air)
how can you describe movement of the ossicles?
small movements, high pressure
allowing for more effective transmission
organ of corti
transducer of the auditory system
inner hair cells
sensory transduction of sound
via cilia that sticks out
outer hair cells
(not transducing)
supplied by efferent nerves
contractile allow stiffening between basilar membrane & tectorial membrane to filter how much energy will be experienced
modulators via alt. how much activation occurs
cilia of inner vs outer hair cells
inner are arranged messier (being embedded in gelatinous membrane) and outer hair cells are in neat chevrons
hair cell mechanics
cilia form bundles @ different heights, when they move they move as a bunch
@ base of basilar membrane?
short, thick fibres
high frequency
@ apex of basilar membrane?
long, thin fibres
low frequency
shearing force
two membranes move at different pivot points
shearing force on hair cells, make them get bent @ deflection of basilar membrane
tectorial membrane movement
moves side to side
basilar membrane movement
up and down
mechanoelectrical transduction via hair cells
high potassium in scala media, therefore inward gradient into cell = depolarisation = Ca2+ influx = NT release activating afferent nerve receptors
via mechanically gated K+ channels
scala media vs scala tympani ion concentrations
media: high K+ low Na+
tympani: low K+ high Na+
how do you encode frequency?
where its coming from on the basilar membrane
auditory pathway to brain
spiral ganglion - auditory nerve - superior olive (brainstem) - medial geniculate (thalamus) - primary auditory cortex
how do we detect location of sound?
inter-aural time difference
detect difference in time for sound to reach, allocating location to plane space
cortical territory (what is it + 2 features)
different frequencies at different place on basilar membrane
unevenly magnified (more interest in speech) & plastic
