Cranial nerves IV

Question 1

what is the sensory ganglion of the facial nerve?

Answer 1

geniculate ganglion

Question 2

what are the two parasympathetic ganglia associated with the facial nerve?

Answer 2

1. pterygopalatine 2. submandibular

Question 3

what are the two nuclei associated with the facial nerve?

Answer 3

1. facial nucleus (motor) 2. superior salivatory nucleus (parasympathetic)

Question 4

taste is projected to what nucleus? via which tract?

Answer 4

to the solitary nucleus via the solitary tract

Question 5

orofacial pain from the facial nerve territory is projected to what nucleus? via what tract?

Answer 5

to spinal V nucleus via the spinal V tract

Question 6

what are the three branches of the facial nerve within the termporal bone? what are their functions?

Answer 6

1. greater petrosal - lacrimation, nasal and salivary secretions 2. chorda tympani - taste 3. nerve to stapedius - hearing

Question 7

the cell bodies of the nervus intermedius reside in which nucleus?

Answer 7

geniculate ganglion

Question 8

how is the hypothalamus involved in taste sensation?

Answer 8

solitary nucleus projects to hypothalamus which mediates visceral responses to unpleasant sensation (gag reflex, vomit reflex)

Question 9

where are nociceptive fibers from the facial nerve (and CN 9 and 10) sent?

Answer 9

spinal tract of trigeminal nerve

Question 10

what is the pattern of termination of the corticonuclear fibers on the facial nucleus?

Answer 10

1. upper half - bilateral corticonuclear projections 2. lower half - contralateral corticonuclear projections

Question 11

Bell’s palsy is due to what type of lesion? on which side?

Answer 11

LMN paralysis lesion affecting entire half of face on ipsilateral side

Question 12

what are the symptoms of Bell’s palsy?

Answer 12

dry eye, hyperacusis, diminished taste sensation, weakness / paralysis on one side of face

Question 13

what are the symptoms of crocodile tear syndrome? what is the cause?

Answer 13

1. patients produce tears instead of saliva when they see / taste food 2. facial nerve lesion in facial canal proximal to geniculate ganglion - axon sprouts that should grow toward submandibular but instead grow to pterygopalatine ganglion

Question 14

what is the pathway of the pyramidal system of conscious, voluntary control of facial muscle movement?

Answer 14

UMNs of corticonuclear tract - facial nucleus in brainstem - LMNs via facial nerve - muscles of facial expression

Question 15

what is the alternate pathway to facial nucleus involved in involuntary, genuine facial expression?

Answer 15

accessory motor areas in frontal lobe and basal ganglia - reticular formation - bilateral projections to facial nucleus - LMNs to muscles of facial expression

Question 16

what are the components of the corneal blink reflex pathway?

Answer 16

1. stimulation of peripheral processes of pseudounipolar neurons in cornea relay to trigeminal ganglion 2. central processes of trigeminal ganglion travel to both the spinal trigeminal nucleus and main sensory nucleus of trigeminal 3. second order neurons synapse at facial motor nucleus which projects to orbicularis oculi muscle via the facial nerve - blinking occurs