Auditory Pathway Flashcards
External ears recieve what waves
sound
Middle ear receives what waves and turns to what
Sound -> mechanical
Inner ear receives what waves and turns to what
Mechanical -> electrical
Why is middle ear high risk space
Connected to nasopharynx Connected to mastoid air cells Connected to IJV Connected to IC artery Traversed by chorda tympani and facial canal
two parts of temporal bone
petrous bone - hardest bone of entire body
squamous bone - flat
inner acoustic meatus has what through it
vestibulocochlear nerve
facial nerve
where does vestibulocochlear nerve terminate
in the petrous part of the temporal
the facial continues on and gives off some branches….
where does the chorda tympani go?
to the tongue
order of small bone hits
malleus to incus to stapes
electrolyte make up of perilymph
high in sodium
low in potassium
mainly made of ECF
allows formation of electrical potentials
what is the cochlear duct?
'a water balloon' membranous sac full of endolymph low in sodium high in potassium more like intracellular fluid
name of two chambers in cochlear duct
which is distal
scala vestibuli
scala tympani
vestibuli is on top
which window does energy waves go through and excess water go out?
in through oval
out through round
so which lymph effects which lymph
perilymph distorts the endolymph in the cochlear duct
roof of the cochlear
vestibular membrane
base of the cochlear
basement/basilar membrane
which layer has hair cells
basement/basilar
what causes an influx of ions?
the cilia produce sheering forces which open ions channels which causes an influx of ions
where are first order fibres contained
spiral ganglion - bipolar neuron
what do the first order fibres go on to form
cochlear nerve which becomes part of vestibulocochlear
where do the first order fibres enter the brain stem
cerebellopontine angle
where do first order synapse with second order neuron
dorsal and ventral cochlear nuclei
where does vestibulocochlear go to
cochlear nuclei
cochlear nuclei go where
superior olivary nucleus
superior olivary nuclei go where
inferior colliculus
inferior colliculus go where
medial geniculate nucleus of the thalamus
medial geniculate fibres go where
the temporal lobe
where so many auditory centres?
Polysynaptic and bilateral
what is bilateral in respect to hearing and how does it work
hearing on both sides so sound can be localised
does this via comparing timing and loudness
from cochlear nuclei, how is the information distributed
to superior olivary nucleus via trapezoid body and slightly more goes to the right hand side
what happens to information in the inf. colliculus
communication between both sides
where and what is the primary auditory cortex
heschl’s gyrus deep in the sup. temporal lobe
how does pitch work in the basilar membrane
apex responds to low pitch and sends this information to anterolateral part of heschl’s gyrus
broca’s area
anterior - motor/production of words
wernicke’s area
posterior - sensory/understanding
secondary auditory areas
broca’s and wernicke’s
which artery feeds broca’s and wernicke’s
middle cerebellar artery
descending fibres pathways for auditory
from cochlear nuclei -> cochlear giving feedback
sup. olivary to stapedius and tensor tympani
inf. colliculus causes reflex head and eye movement
Superior olivary nucleus sends motor fibres to what via what
Why
To stapedius via CNVII
To tensor tympani via CNV3
Prevents damage during loud noise
Inf. colliculus sends motor fibres to what via what
Why
Reflex head and eye movements
CNIII, VI
