Is the facial nerve sensory, motor or mixed?
Describe the branchial motor supply of the facial nerve?
this is the major role...
efferent supply to the ipsilateral muscles of facial expression and the stapedius
Describe the visceral motor function of the facial nerve
sends preganglionic parasympathetics to the lacrimal, sumandibular, and sublingual glands
Describe the somatic sensory properties of the facial nerve.
afferent supply to the ipsilateral part of outer ear, nasal cavity and soft palate
Describe the visceral (special) sensory properties of the facial nerve
ipsilateral affterent supply for TASTE to the anterior 2/3 of the tongue
Where is the facial motor nucleus located?
in the ventrolateral caudal pons
Where do ribers leave the facial motor nucleus?
exit up and over the abducens at the genu and then out from the lasteral pons
What will damage to the facial nerve or its motor nucleus cause?
paralysis of the muscles on the same side of the face
Describe the corneal blink reflex. What two CN are involved?
CN 5 and 7:
You touch the cornea and sensory efferents travel in V2 to the trigeminal ganglion and then descend in the spinal trigeminal tract to the rostral spinal trigeminal nucleus.
output from the spinal trigeminal nucleus it to BILATERAL motor nuclei of the facial nerve
efferents from the motor nuclei of the facial nerve to the orbicularis oculi cause the bilateral blink.
What is special about coricobulbar tract output to the facial motor nuclei?
Most output is bilateral to cranial nerve nuclei, but that's not the case with the facial motor nucleus - it's different depending on where you are on the face:
lower half of the face: corticobulbar fibers to the motor neurons are contralateral
upper half: corticobulbar fibers are distributed bilaterally
Because of the odd corticobulbar innervation to the facial nerve, what will UNILATERALcorticobulbar damage cause?
weakness of only the contralateral LOWER quadrant of the face
Paralysis of the entire left face resulted from what type of lesion?
The ipsilateral lowe rmotor neuron
Paralysis of the left lower face only resulted form what type of lesion?
contralateral upper rmotor neuron damage
Is bell's palsy a lowe rmotor neuron lesion or an upper motor neuron lesion?
lower motor neuron - you get paralysis of entire ipsilateral face