Facial Nerve (CN VII)

Question 1

what are the 6 fxns of the facial n.?

Answer 1

mm. of facial expression, including closing eyelids
lacrimation (crying)
mucous production in the nasopharyngeal region
salivation fron sublingual and submandibular glands
taste from the anterior 2/3 of the tongue
dampening abrupt, loud noises

Question 2

what types of nn. run in the facial n.?

Answer 2

motor- to mm. of facial expression (plus a few extra)
autonomic- to lacrimal and salivary glands, to mucous glands of the nose and palate
general sensory- sensation from the skin around the outer ear
special sensory- taste from the anterior 2/3 of the tongue

Question 3

where are the cell bodies of the motor component of the facial n.?

Answer 3

pons of the brainstem

Question 4

what does the motor component of the facial n. innervate?

Answer 4

mm. derived from the 2nd pharyngeal arch

Question 5

what is the route of the motor component of the facial n.?

Answer 5

exit the cranial cavity through the internal auditory meatus, then travels in the facial canal just posterior to the ear and descends to exit the stylomastoid foramen

Question 6

what happens when the facial n. enters the parotid gland on its way to the mm. of facial expression?

Answer 6

splits into 5 branches:
Temporal
Zygomatic
Buccal
Mandibular
Cervical

Question 7

a few fibers split off to innervate which mm.?

Answer 7

stylohyoid, post belly of digastric, occipitalis, post auricularis mm.

Question 8

one br of the facial n. comes of in the facial canal to innervate what mm. and for what action?

Answer 8

stapedius

dampens sudden, loud sounds

Question 9

damage to the motor component of the facial n. cause what?

Answer 9

loss of mm. of facial expression on that side of the face

hyperacusis

Question 10

where are the cell bodies of the general sensory component of the facial n.?

Answer 10

geniculate ganglion

Question 11

how to central process of the general sensory component get to the brainstem?

Answer 11

central processes project through nervus intermedius of CN VII to the brainstem

Question 12

what is the course of the general sensory component of the facial n.?

Answer 12

peripheral processes go in CN VII as it descends in the facial canal to provide sensation to skin covering the external auditory meatus and some skin of the auricle of the ear

Question 13

damage to the general sensory component of the facial n. would cause what?

Answer 13

minor loss of sensation around the ear

Question 14

where are the cell bodies of the special sensory component of the facial n.?

Answer 14

geniculate ganglion

Question 15

how to central process of the special sensory component get to the brainstem?

Answer 15

central processes project through nervus intermedius of CN VII to the brainstem

Question 16

from where does the taste from the palate come in?

Answer 16

via the greater petrosal n.

Question 17

from where does the taste from the anterior 2/3 of the tongue come in?

Answer 17

chorda tympani

Question 18

damage to the special sensory component of the facial n. would cause what?

Answer 18

some loss of taste from these areas

Question 19

what type of autonomic fibers run in the facial n.?

Answer 19

preganglionic parasympathetic fibers

Question 20

what do the autonomic fibers in the facial n. innervate?

Answer 20

lacrimal gland
mucous glands of nose, palate, and pharynx
submandibular and sublingual glands

Question 21

where are the cell bodies of the autonomic fibers of the facial n.?

Answer 21

superior salivatory nucleus of the brainstem

Question 22

autonomic fibers to the sublingual and submandibular glands run through what?

Answer 22

chora tympani

Question 23

autonomic fibers to the sublingual and submandibular glands synapse where?

Answer 23

submandibular ganglion

Question 24

after autonomic fibers synapse in the submandibular ganglion what happens?

Answer 24

postganglionic parasympathetic fibers go to the glands

Question 25

autonomic fibers to the nose, palate, and pharynx run through what?

Answer 25

greater petrosal n.

n. of pterygoid canal

Question 26

autonomic fibers to the nose, palate, and pharynx synapse where?

Answer 26

pterygopalatine ganglion

Question 27

after autonomic fibers destined for the nose, palate, and pharynx synapse in the pterygopalatine ganglion what happens?

Answer 27

postganglionic parasympathetic fibers go to the glands

Question 28

autonomic fibers to the lacrimal gland run through what?

Answer 28

greater petrosal n.

n. to pterygoid canal

Question 29

autonomic fibers to the lacrimal gland synapse where?

Answer 29

pterygopalatine ganglion?

Question 30

after autonomic fibers destined for the lacrimal gland synapse in the pterygopalatine ganglion what happens?

Answer 30

postganglionic parasympathetic fibers go through br. of CN V2 to the lacrimal br. of V1 then to the lacrimal gland

Question 31

damage to the autonomic component of the facial n. would cause what?

Answer 31

slight dry mouth, decreased nasal secretions, DRY EYES

Question 32

How do you test for facial n. fnxn?

Answer 32

raise eyebrows
close eyes tightly
show teeth
pull corners of mouth laterally and inferiorly

Question 33

what is bell’s palsy?

Answer 33

loss of all the mm. of facial expression on one side of the face

Question 34

what happens in a stroke?

Answer 34

loss of mm. of facial expression only below the eyebrow on one side of face