Auditory pathway Flashcards
where is the auditory pathway located int he skull?
the petrous part of the temporal bone
why is the middle ear a high risk space?
IT is connected to nasopharynx and mastoid air cells so prone to infection
internal jugular vein lies inferior creating a risk of thrombosis
internal carotid arter lies anterior - link to pulsatile tinnitus
what are the three cavities in the petrous part of the temporal bone?
vestibule
semicircular canal
cochlea
what type of fluid does the cochlea contain?
PERILYMPH
what type of fluid does the cochlear duct contain?
ENDOLYMPH
what is the cochlear duct?
a membranous sac running through the cochlear
filled with endolymph
what are the two chambers the cochlear duct separates the cochlea into?
the scala vestibuli and scala tympani
where does the scala vestibuli lie in relation to the cochlear duct?
above the cochlear duct
where does the scala tympani lie in relation to the cochlear duct?
below the cochlear duct
what is the helicotrema?
the apex of the cochlea where the scala vestibuli and scala tympani are continuous
what is the roof of the cochlear duct formed by?
the vestibular membrane
what is the floor of the cochlear duct formed from?
the basement or basilar membrane
what is the auditory receptor?
the spiral organ of corti
where is the spiral organ of corti located?
on the basilar membrane
what do the primary auditory fibres do in the auditory pathway
they form the cochlear nerve which becomes part of the vestibulocochlear nerve that enters the brainstem at the cerebellopontine angle
where does the primary auditory neurone synapse with the secondary?
in ventral and dorsal cochlea nuclei
where does neuron pass to after the cochlear nuclei?
the superior olivary nucleus
where does the neuron pass after the superior olivary nucleus?
the inferior colliculus - this is in the midbrain and fibres may cross here
where does it go after the inferior colliculus?
medial geniculate nucleus
where does it go after the medial geniculate nucleus of the thalamus?
Heschl’s gyrus of cerebral cortex
where does the neurone travel in the lateral lemniscus?
between the superior olivary nucleus and the inferior colliculus
where does the neuron travel in the inferior brachium?
from the inferior colliculus to the medial geniculate nucleus
where is the neuron travelling in the trapezoid body
from the cochlear nuclei to the superior olivary nucleus
what is the basics of the auditory pathway?
from the cochlear nuclei the neurone travels in the trapezoid body to the superior olivary nucleus. the neurone then travels in the lateral lemniscus to the inferior colliculus. the neurone then travels in the inferior brachium to the medial geniculate nucleus. then from the medial geniculate nucleus to heschl’s gyrus in the cortex
