Hearing & Balance pt.2 (II) Flashcards
where is the A1 located
- on superior temporal lobe
- within sylvian fissure
where do pure tones activate?
temporal lobe
ventral stream
- temporal lobe
- pitch, volume, tone
- receives info from 1 ear (contralateral projection from brain stem)
wernicke’s area
- speech sound information
- language and comprehension
- cerebral hemisphere (junction between temporal and parietal lobe)
wernicke’s aphasia
- damage to wernicke’s
- can’t understand what people are saying
why do songs get stuck in your head
- cortical volume of heschl’s gyrus is smaller in people who are prone to earworms
- frontal lobe inhibition centers are physically smaller in these people
hearing loss
- reduced capacity to interpret sound
deafness
- profound inability to hear
what are the 3 main causes of hearing loss and deafness
- conduction deafness
- sensorineural deafness
- central deafness
conduction deafness
- disorders of the outer ear or middle ear that prevent sounds from reaching the cochlea
sensorineural deafness
- originates from cochlear or auditory nerve lesions
central deafness
- caused by brain lesions such as stroke
teflon prosthetics
- for fused ossicles (can be genetic)
cochlear implants
- deafness due to hair cell loss
- electrical currents stimulate the auditory nerve
hearing aids
- electronic amplification to deliver louder sounds to the impaired (but still functional) auditory system
motion sick and car sick
faulty vestibular system
functions of vestibular system
- detects position and movement of the head
2. generates compensatory movements/body position adjustments to maintain posture
vestibular labyrinth
- located in inner ear
next to cochlea - vestibular system
semicircular canals
- vestibular system
- 3 fluid filled tubes in different planes
otolith organs
- vestibular system
- fluid filled sac that responds to movement
nodding up and down
semicircular canals
tilting left and right
semicircular canals
shaking side to side
semicircular canals
what does movement of head do in relation to semicircular canals
- pushes endolymph through canals to the ampulla
ampulla
- located at the end of each canal
- contains hair cells surrounded by cupula (gelatinous) coating
what does endolymph moving/bending result in?
distors cupula (cilia of hair cells) similar to the auditory system
- opens K+ ion channels
- depolarization opens Ca2+ channels
- glutamate released into synapse with CN8 (vestibulocochlear)
motion sickness
- mismatch between vestibular and visual inputs
role for area postrema
- brain believes you must be hallucinating
- triggers vomiting
cerebellum
- vestibular pathways: balance and gait control (helping you move around)
aka motor correction
midbrain (tectum)
- vestibular pathways: eye movements
spinal cord
- vestibular pathways: (vestibulospinal tract) postural and balance movements
function of otolith organs
- inner ear, detect forward and backward movement
- horizontal and vertical acceleration
utricle
- otolith organ
- for horizontal movement
saccule
- otolith organ
- for vertical movement
otoconia
tiny calcium carbonate crystals
how does the otoconia affect when the head changes position
added weight from the otoconia produces drag on the hair cells when it changes
when the head changes position what happens
- opening of K+ channels depolarizes hair cell
2. results in Ca2+ influx and glutamate release into vestibulocochlear nerve
