Cranial Nerve VIII, Auditory Systems and Auditory Tract Flashcards
adequate stimulus for auditory
air pressure waves
inner ear
transfer vibration to perilymph of bony labyrinth
inner ear
transduction of signal
primary afferents for CN VIII
cell bodies in spiral ganglion
auditory ossicles
malleus, incus, stapes
create lever system that transfers 60% of energy to inner ear
course of inner ear
stapes > oval widow > scala vestibuli > scala tympani > round window
CN VIII circuit
to cochlear nuclei
-then bilateral
trapezoid body
connect cochlear nuclei to superior olive bilaterally
lateral lemniscus
connect superior olive to inferior colliculus
CN VIII pathway
primary afferent (spiral ganglion) > cochlear nuclei > trapezoid body > superior olive > lateral lemniscus > inferior colliculus > brachium of inferior colliculus > medial geniculate nucleus (thalamic relay) > auditory cotex
medial geniculate nucleus
prethalamic relay for CN VIII pathway
transverse temporal gyri
destination of input from CN VIII
-from medial geniculate nuclei
primary auditory cortex
brodmans 41 and 42
conduction deafness
failure to conduct vibrations from external ear to vestibular window
sensorineural deafness
transduction failure or failure to transmit APs to CN VIII
