Facial Nerve (CN VII) Flashcards
what are the 6 fxns of the facial n.?
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
what types of nn. run in the facial n.?
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
where are the cell bodies of the motor component of the facial n.?
pons of the brainstem
what does the motor component of the facial n. innervate?
mm. derived from the 2nd pharyngeal arch
what is the route of the motor component of the facial n.?
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
what happens when the facial n. enters the parotid gland on its way to the mm. of facial expression?
splits into 5 branches: Temporal Zygomatic Buccal Mandibular Cervical
a few fibers split off to innervate which mm.?
stylohyoid, post belly of digastric, occipitalis, post auricularis mm.
one br of the facial n. comes of in the facial canal to innervate what mm. and for what action?
stapedius
dampens sudden, loud sounds
damage to the motor component of the facial n. cause what?
loss of mm. of facial expression on that side of the face
hyperacusis
where are the cell bodies of the general sensory component of the facial n.?
geniculate ganglion
how to central process of the general sensory component get to the brainstem?
central processes project through nervus intermedius of CN VII to the brainstem
what is the course of the general sensory component of the facial n.?
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
damage to the general sensory component of the facial n. would cause what?
minor loss of sensation around the ear
where are the cell bodies of the special sensory component of the facial n.?
geniculate ganglion
how to central process of the special sensory component get to the brainstem?
central processes project through nervus intermedius of CN VII to the brainstem
from where does the taste from the palate come in?
via the greater petrosal n.
from where does the taste from the anterior 2/3 of the tongue come in?
chorda tympani
damage to the special sensory component of the facial n. would cause what?
some loss of taste from these areas
what type of autonomic fibers run in the facial n.?
preganglionic parasympathetic fibers
what do the autonomic fibers in the facial n. innervate?
lacrimal gland
mucous glands of nose, palate, and pharynx
submandibular and sublingual glands
where are the cell bodies of the autonomic fibers of the facial n.?
superior salivatory nucleus of the brainstem
autonomic fibers to the sublingual and submandibular glands run through what?
chora tympani
autonomic fibers to the sublingual and submandibular glands synapse where?
submandibular ganglion
after autonomic fibers synapse in the submandibular ganglion what happens?
postganglionic parasympathetic fibers go to the glands
autonomic fibers to the nose, palate, and pharynx run through what?
greater petrosal n.
n. of pterygoid canal
autonomic fibers to the nose, palate, and pharynx synapse where?
pterygopalatine ganglion
after autonomic fibers destined for the nose, palate, and pharynx synapse in the pterygopalatine ganglion what happens?
postganglionic parasympathetic fibers go to the glands
autonomic fibers to the lacrimal gland run through what?
greater petrosal n.
n. to pterygoid canal
autonomic fibers to the lacrimal gland synapse where?
pterygopalatine ganglion?
after autonomic fibers destined for the lacrimal gland synapse in the pterygopalatine ganglion what happens?
postganglionic parasympathetic fibers go through br. of CN V2 to the lacrimal br. of V1 then to the lacrimal gland
damage to the autonomic component of the facial n. would cause what?
slight dry mouth, decreased nasal secretions, DRY EYES
How do you test for facial n. fnxn?
raise eyebrows
close eyes tightly
show teeth
pull corners of mouth laterally and inferiorly
what is bell’s palsy?
loss of all the mm. of facial expression on one side of the face
what happens in a stroke?
loss of mm. of facial expression only below the eyebrow on one side of face
