hearing and equilibrium Flashcards
what is in the middle ear
malleus, incus, stapes
where is the pinna
external ear
what is in the inner ear
semicircular canals, oval window, cochlea, vestibular apparatus
what separates inner fluid fillled ear from the air filled middle ear
round window and oval window
what separates outer and middle ear
tympanic membrane
what is percieved during hearing
frequency and amplitude
what is measured in hertz
frequency
what is measured in dB
amplitude
what is loudness
amplitude
hat is pitch
frequency
hearing process
sound waves strike tympanic membrane and become vibrations
sound wave E is transferred to the three small bones which vibrate
stapes attached to oval window membrane vibrations transfer to fluid waves in cochlear
fluid waves push on flexible cochlear ducts and hair cells bend and ion channels open creating electrical signal-altering neurotransmitter release
neurotransmitter release onto sensory neurons creates AP that travel through cochlear nerve to brain
some energy waves from cochlear duct into tympanic duct and dissipated back into middle ear at round window
what initiates neural pathway of auditory perception
hair cells in cochlear duct
what does increased depolarization of hair cells lead to
increased AP rate of sensory neurons
what moves and depolarizes in response to fluid waves
cilia of hair cells
what synapses with nerve fibres of cochlear nerve
hair cells
where do cochlear nervee info feed into
auditory cortex
what is detected at narrow stiff region of basilar membrane
high frequency
what is detected in the wide flexible region of basilar membrane
low frequency
what does loudness lead to
more rapid firingof sensory neurons
where is transformation of temporal aspects retained
in auditory cortex like piano keyboard
mix of all frequencies
white noise
a blend of high and low freq
pink noise
low freq to generate deep rumble
brown noise
what is the pathway of ascending tracts of sound signals
are split at the medullar between left and right brain
what is integrative and requires simultaneous input from both ears
sound localization
normal speaking db
60
hamful db
greater than 85
VOR
mediates unblurred vision during head movement like walking and running via opposite eye movement
what causes opposite eye movemnt in VOR
extraocular muscle move at the same velocity as the head movement. keeps our line of sight fixed on tsame point in visual space both during and following eye movement
eye towards nose
medial rectus
eye away from nose
lateral rectus
eye up
superior rectus
eye down
inferior rectus
down towards nose in primary gaze
superior oblique
upward towards temple in primary gaze
inferior oblique
what detects angular acceleration/ rotational acceleration
cupulae of the cristeae of the ampulae o fthe semicircular canals in the vestibular apparatus
what stimulates hair cells
movement of the endolymph bends the cupula
what does the primary vistibular afferent consist of
head angular rotational velocity info detected by hair cells of the cupula of the cristae ampullarae of the semicircular canals in the inner ear
what is the 1st order in the 3 neuron VOR arc
primary vistibular afferent from cristae ampullarae of horizontal canals to vestibular interneurons in the medial vestibular nucleus
2nd order in VOR reflex
vestibular internerons to abducens nucleus
3rd order in VOR
abducens nucleus to extraocular lateral rectus muscle motorneurons
what maintains binocular eye alignment
abducens nucleus to internuclear neurons to to contralateral pool of extraocular medial rectus motorneurons
combination of alternating slow and fast phase eye movements in opposite directions
nystagmus
compensatory eye movements are within limits of eye rotatoin
short head moveements
eye reaches limit of excursion before head moveemnt is complete. at eyes extreme position, it is rapidly flicked back to a new starting position
large amplitude head movements
what bends cupula
shifting of endolymph
the afferent VOR
hair cells
what detects linear acceleration or movement
maculae sensory strucures of otolith organs (utricle and saccule) of vestibular apparatus
what stimuates hair cells in linear acceleration
position shifts of the otolith drags the otolith membrane
what separated the fluid filled innner ear from the air filled middle ear
oval window and round window
where are the semincurcular canals
in the inner ear
what consists of head angular rotational velocity inforamtion
primary vestibular afferent
superior oblique direction
down towards nose
medial rectus dierction
towards nose
lateral rectus direction
away from nose
superior rectus direction
upwards
what direction do oblique muscles in eyes go
opposite of name
what direction do rectus muscles in eye go
according to name
