Cranial Nerves (VII-XII) Flashcards
Functions of Facial Nerve
Motor SVE - muscles of face (facial
expression) and scalp, stapedius muscle, posterior belly of digastric, stylohyoid muscles
Sensory SVA - taste from anterior 2/3 of tongue from floor of mouth and palate
Sensory GSA - sensation from a small region near the external auditory meatus
Parasympathetic GVE - secretomotor to submandibular and sublingual glands, lacrimal glands and glands of nose and
palate
Carries brachial motor fibers for facial expression
Main Trunk
In facial nerve, Carries fibers for PSY (tearing and salivation), taste, and GSA
Nervus Intermedius
3 nuclei of facial nerve
- Main Motor Nucleus
- Parasympathetic Nuclei
● Superior salivatory nucleus
● Lacrimal nucleus - Sensory Nucleus
● Nucleus tractus solitarius
● Trigeminal nucleus
Facial nucleus
Lies deep in the reticular formation of the
lower part of the pons
Part of the nucleus supplies muscles of the
upper part of the face receives fibers from
both cerebral hemispheres
Main Motor Nucleus
Motor cortex supplying lower part of face
contralateral side of motor
cortex
Motor cortex supplying upper part of face
both sides of motor cortex
facial nuclei that Lie posterolateral to the main motor nucleus
parasympathetic nuclei
Parasympathetic nucleus of facial nerve that receives afferent fibers from thalamus through descending autonomic pathways
Superior Salivatory Nucleus
PSY facial nuclei that Receives afferent fibers from hypothalamus
for emotional responses and from sensory
nuclei of trigeminal nerve for reflex
lacrimation due to irritation
Lacrimal Nucleus
has Afferent fibers: geniculate ganglion of CN VII
Efferent fibers cross midline and ascend to VPM of opposite thalamus
Nucleus of Tractus Solitarius
Upper part (rostral) of nucleus of tractus solitarius
sensory nuclei
● formed of Central processes of unipolar cells of
geniculat ganglion
● Also contain efferent preganglionic PSY
fibers from parasympathetic nuclei
Sensory Root (nervus intermedius)
lies in the genu and
contains primary sensory neurons for taste in anterior ⅔ of tongue, GSA for a region
near external auditory meatus
Geniculate ganglion
Main portion of facial nerve exits the skull through
stylomastoid foramen
facial nerve Pass through the parotid gland and divides
to 5 major brachial motor branches that control facial expression
○ Temporal
○ Zygomatic
○ Buccal
○ Mandibular
○ Cervical
○ Other smaller motor branches
innervate the stapedius, occipitalis,
posterior belly of digastric, and
stylohyoid muscles
Dampen movements of middle ear
ossiclesproviding feedback
modulation of acoustic signal
intensity
stapedius
tensor tympani innervated by
trigeminal
carried by greater
petrosal nerve (takes off the main trunk of CN VII) to reach sphenopalatine
(pterygopalatine) ganglion where
postganglionic PSY project to lacrimal
glands and nasal mucosa
Preganglionic PSY fibers from Superior
Salivatory Nucleus
leaves CN VII just before
the stylomastoid foramen and travels back
upward to traverse the middle ear cavity
before exiting the skull at the petrotympanic
fissure, just medial to the TMJ.
Chorda tympani
Chorda tympani carry
SVA taste for anterior
⅔ of tongue