20 (pt 2) Auditory and Vestibular System Flashcards
external ear
pinna
auditory canal
middle ear
tympanic membrane
ossicles
oval window
muscles
what separates the outer ear and inner ear
tympanic membrane
ossicles
malleus, incus, and stapes transfer movement of the tympanic membrane to movement of the oval window
important for sound force amplificaton
oval window
membrane covering a hole in the skull that transmits vibrations to the cochlea
foot plate
the bottom part of the stapes that is connected to the oval window
movement of footplate moves oval window
two parts of inner ear
auditory apparatus: cochlea
vestibular apparatus: semicircular canals, utricle, saccule
3 fluid filled chambers of the cochlea
scala vestibuli
scala media
scala tympani
organ of corti
part of the cochlea that contains the auditory receptor cells → initiate mechanoelectrical transduction
basilar membrane
vibrates in response to sound
mechanoelectrical transduction
sound wave hits tympanic membrane → ossicles move, causing vibration of membrane at opening of cochlea → fluid in cochlea moves → basilar membrane and embedded hair cells to vibrate → hair cells bend against tectorial membrane → hair cells depolarize → cochlear nerve endings activated
location of auditory cortex
temporal lobe
brainstem auditory center
cochlear nuclei: medulla
superior olive: pons
lateral lemniscus: pons
inferior colliculi: midbrain
superior olive function
sound localization
lateral leminiscus function
transmits sound information from the cochlear nuclei to inferior colliculus.
inferior colliculus function
processes sound frequencies
sound localization
superior colliculus functon
orients eyes and head toward direction of sound
primary auditory cortex
determines intensity of sounds
secondary auditory cortex
classifies sounds
memories of sounds
peripheral vestibular system
semicircular canals
otoliths
semicircular canals
rotational acceleration
anterior: flex/ext
posterior: side bending
horizontal: rotation
otoliths
linear acceleration
utricle: horizontal movements
saccule: vertical movements
ampulla vs. cupulla
ampulla: base of semicircular canal
cupula: is a gelatinous structure that sits on top of the crista inside the ampulla.
crista
sensory organ in the ampulla
macula
specialized sensory regions in the otolith organs which are responsible for detecting linear acceleration and head position relative to gravity.
synonymous to cupulla of SCC
semicircular canal functional pairs
R/L horizontal SCCs
R anterior/L posterior SCCs
R posterior/L anterior SCCs
otoconia
calcium carbonate crystals in the macula that move on top of the gel later to bend the hair cells
info is converted to neural signals to the vestibular nerve to which lobe of the cerebellum
vestibulocerebellum (flocculonodular lobe)
central vestibular system
vestibular nuclei
6 pathways
vestibulocerebellum
vestibular cortex
descending vestibular pathways
vestibulospinal tracts
vestibuloreticular pathway
vestibulocolic pathway
medial vestibulospinal tract
Head/neck stabilization via neck muscles
- vestibulo-cervical reflex
vestibulo-cervical reflex
postural adjustments of head in response to activation of SCCs
lateral vestibulospinal tract
postural control via extensor muscles
-vestibulo-spinal reflex
vestibulo-spinal reflex
postural and tone adjustments of body
vestibulocolic pathway
goes to CN XI nucleus to affect cervical muscles’ postural control
what results from disrupted descending pathways
balance deficits which impacts movement abilities/control
ascending vestibular pathways
vestibulothalamocortical pathway
vestibulocerebellar pathways
medial longitudinal fasciculus
where do ascending vestibular pathways start?
vestibular nuclei
vestibulothalamocortical pathway
Vestibular nuclei → Thalamus → Vestibular cortex (posterior parietal cortex)
Perception of balance, spatial orientation
vestibulocerebellar pathways
medial longitudinal fasciculus
vestibular nuclei → CN III, IV, VI
mediates VOR → influences eye and head movements
