Will Stephan Pass Bio 33?

Facial Nerves


Facial nerves leave the brain stem and weave their way thru the temporal bone through the internal acoustic meatus, coming out through the stylomastoid foramen to reach the face.
The noive,er,NERVE then goes to five of the facial muscles:
A. the temporal,
B. the zygomatic,
C. the buccal,
D. the mandibular and
E. the cervical muscles.
These are all somatic motor neurons.
(image courtesy of http://www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/h_n/cn/cn1/mainframe.htm)

The facial nerve is mixed, since besides motor neurons, they are also parasympathetic and sensory. The parasympathetic motor impulses go to:
- lacrimal (tear) glands
-nasal and paltine glands
-submandibular and sublingual salivary glands

(image courtesy of http://tmjc.com.ne.kr/tmj/info/drinfo/tmjneed7.htm)

As far as senses go, sensory inpulses come from the tongue(first two-thirds of it.)
The facial nerve is tested sensory-wise by giving the subject sweet, salty, sour and bitter substances. The motor neuron efficiency is tested by asking the subject to close eyes, smile, whistle(which i never learned to do, uh oh, i'd fail this one), and so on. Tearing is tested by using ammonia fumes on the subject, or withholding the treat i was promised for taking part in this test.