113. Facial nerve. Nuclei – position, characteristic. The course, branches, area of distribution.

FACIAL NERVE

• The facial nerve is the seventh cranial nerve (CN VII).
• It is a mixed nerve responsible for various functions include:
• Motor: to muscles that developed from the 2nd pharyngeal arch = muscles of facial expression + platysma, posterior belly of digastric m. + stylohyoid m.
• Sensory: Carries special sensations (taste) from anterior 2/3 of the tongue and soft palate ← special sensory. It also carries general sensations from concha of the ear. → Somatic (general) sensory
• Parasympathetic: to lacrimal gland + submandibular gland & sublingual salivary glands. visceral motor
• The facial n. arise from two divisions: a motor root & a smaller sensory root. (Intermediate nerve)

Functional componants & nuclei

Nuclei — Fibers

1. Motor nucleus - Special visceral Efferent (SVE)

• at lower pontine tegmentum.
• Its fibers loops around the abducent nerve nucleus forming (Facial colliculus).

2. Superior salivatory nucleus. _ General Visceral Efferent (GVE)

• Parasympathatic nuclei.

3. nucleus of solitary tract _ Special Visceral Sensory Afferent (SVA)

• From tongue anterior 2/3 → Geniculate ganglion → upper part of solitary nu.

* Sensory fibers that carry information from peripheral receptor to the CNS often have associated ganglia.

4. Spinal nucleus of trigeminal nerve — General Somatic Afferent (GSA)

• Sensory nucleus