Cranial nerves V

Question 1

what is the pathway for first order neurons of the auditory pathway?

Answer 1

1. peripheral processes - receptor hair cells 2. cell bodies - spiral ganglion 3. central processes - form root of cochlear nerve and enters pons, bifurcate and synapse in dorsal and ventral cochlear nuclei

Question 2

what is the pathway for second order neurons of the auditory pathway?

Answer 2

1. cell bodies - dorsal and ventral cochlear nuclei (pons) 2. ventral nucleus axons - ventral stria (trapezoid body) terminate in nucleus of trapezoid body, superior olivary nucleus, nucleus of lateral lemniscus, inferior colliculus 3. dorsal nucleus axons - dorsal stria terminate in inferior colliculus (via lateral lemniscus)

Question 3

where are the third order neurons of the auditory pathway?

Answer 3

1. cell bodies - superior olivary nuclei (localization) 2. carry information from both ears

Question 4

what is the “main pathway” of the auditory system?

Answer 4

lateral lemniscus to inferior colliculus

Question 5

what is the input and output of the inferior colliculus?

Answer 5

1. input - lateral lemniscus 2. output - medial geniculate nucleus

Question 6

what is the role of the medial geniculate nucleus? what does it give rise to?

Answer 6

1. processes sound intensity and frequency 2. auditory radiation - projects to auditory cortex

Question 7

what is the role of the primary auditory cortex? secondary?

Answer 7

1. primary - localization of sound, detecting alterations in pattern 2. interpretation of sound, voice, language, music

Question 8

what are the descending auditory projections? what is their role?

Answer 8

1. olivocochlear bundle 2. modulates transmission of auditory input to CNS

Question 9

what is the pathway for first order neurons of the vestibular pathway?

Answer 9

1. peripheral processes - hair cells in maculae of utricle and saccule; cristae of semicircular canal ampullae 2. cell bodies - vestibular ganglion 3. central processes - form root of vestibular nerve, enter pons and bifurcate in vestibular nuclei to go to inferior cerebellar peduncle / flocculonodular lobe of cerebellum

Question 10

what is the pathway for second order neurons of the vestibular pathway?

Answer 10

1. cell bodies - vestibular nuclei 2. axons join medial longitudinal fasciculus to go to eye muscles, reticular formation, cervical spinal cord, cerebellum, thalamus

Question 11

what is the pathway for third order neurons of the vestibular pathway?

Answer 11

1. cell bodies - VPL and VPI nuclei of thalamus 2. project to primary vestibular cortex

Question 12

what is the SVA of CN 9? GSA?

Answer 12

1. SVA - taste from posterior 1/3 of tongue 2. GSA - general sensation from posterior 1/3 of tongue

Question 13

what are the sensory ganglia of CN 9?

Answer 13

1. superior ganglion 2. inferior (petrosal) ganglion

Question 14

what is the pathway of pseudounipolar central processes from the superior ganglion of CN 9?

Answer 14

descend in spinal V tract to spinal V nucleus (GSA)

Question 15

what is the pathway of pseudounipolar central processes from the inferior ganglion of CN 9?

Answer 15

join solitary tract to terminate in solitary nucleus (GVA, SVA)

Question 16

what is the parasympathetic ganglion of CN 9? what is the course of its postganglionic axons?

Answer 16

1. otic 2. terminate in parotid gland

Question 17

what are the nuclei associated with CN 9?

Answer 17

1. inferior salivatory 2. nucleus ambiguus 3. solitary nucleus

Question 18

what is contained in the inferior salivatory nucleus? where do its axons terminate?

Answer 18

1. cell bodies of preganglionic parasympathetic neurons (GVE)2. otic ganglion

Question 19

what is contained in the nucleus ambiguus?

Answer 19

cell bodies of motor neurons

Question 20

what is contained in the solitary nucleus?

Answer 20

receives central processes of GVA and SVA neurons

Question 21

what are the nuclei of the vagus nerve? what are their functions?

Answer 21

1. dorsal motor nucleus - parasympathetic 2. nucleus ambiguus - motor (larynx, pharynx) 3. solitary nucleus - taste and visceral sensory; receives fibers from CN 7, 9, 10

Question 22

what are the ganglia of the vagus nerve?

Answer 22

1. superior (jugular) 2. inferior (nodose) 3. parasympathetic

Question 23

what is the pathway of the pseudounipolar central processes of the superior (jugular) ganglion of CN 10?

Answer 23

descend in spinal V tract to spinal V nucleus

Question 24

what is the pathway of the pseudounipolar central processes of the inferior (nodose) ganglion of CN 10?

Answer 24

join solitary tract to terminate in solitary nucleus