Cranial Nerves Pt2 Flashcards
What are the branchial motor/SVE functions of the facial nerve (CN VII)?
To supply the stapedius, stylohyoid, posterior belly of digastric, muscles of facial expression including buccinator, platymsa and occipitalis muscles
What is the visceral motor/GVE function of CN VII?
For stimulation of the lacrimal, submandibular and sublingual glands as well as the mucous membrane to the nose and hard/soft palate
What is the general sensory/GSA function of CN VII?
To supply the skin of the concha of auricle, small area of skin behind the ear, possibly to supplement V3 which supplies the wall of the acoustic meatus and external tympanic membrane
What is the special sensory function of CN VII (facial)?
For taste from the anterior 2/3 of the tongue and hard and soft palates
What are two important branches of the CN VII?
Chorda tympani and greater petrosal nerves
What are conditions caused by damage to CN VII?
Decreased tearing (dry eye) and decreased salivation (dry mouth), loss of taste sensation to anterior 2/3 of tongue and/or facial nerve palsy (sometimes called Bell palsy) characterized by paralyzed facial muscles, eyelid droop, sagging at corner of mouth
Branches of facial nerve (CN VII
A tiny zebra bit my cheek Posterior superior auricular Temporal Buccal Mandibular Cervical branch
What does the facial nerve pass through to innervate muscles of facial expression?
Stylomastoid foramen
Deep petrosal nerve of CN VII is what?
Postganglionic sympathetics
Greater petrosal nerve and chorda tympani of CN VII are what?
Preganglionic parasympathetic
Chorda tympani is also special sense (taste)
Describe visceral (parasympathetic) motor innervation to lacrimal gland
Greater petrosal nerve arises from CN VII at geniculate ganglion and emerges from superior surface of petrous part of temporal bone to enter middle cranial fossa ->
Greater petrosal nerve joins deep petrosal nerve (sympathetic) at foramen lacerum to form nerve of pterygoid canal ->
Nerve of pterygoid canal travels through pterygoid canal and entered pterygopalatine fossa ->
Parasympathetic fibers from nerve of pterygoid canal in pterygopalatine fossa synapse in pterygopalatine ganglion ->
Post synaptic parasympathetic fibers from this ganglion innervate lacrimal gland via zygomatic branch of CN V2 and lacrimal nerve branch
Describe visceral (parasympathetic) motor innervation to submandibular and sublingual glands
Chorda tympani branch arises from CN VII just superior to stylomastoid foramen ->
Crosses tympanic cavity medial to handle of malleus ->
Passes through petrotympanic fissure b/w tympanic and petrous parts of the temporal bone to joint the lingual nerve (CN V3) in infratemporal fossa ->
Parasympathetic fibers of chorda tympani synapse in submandibular ganglion and postsynaptic fibers follow arteries to glands
What is the special sensory function of the CN VIII (vestibulocochlear)?
Auditory info from the cochlea (cochlear) and balance information from the semicircular canals (vestibular)
Where does CN VIII originate?
Vestibular branch: hair cells in the vestibule of the inner ear
Cochlear: cochlea of the inner ear
What is the pathway of CN VIII?
Sensory cell bodies of vestibular branch are located in the vestibular ganglion, while sensory cell bodies of the cochlear branch are located in the spiral ganglion near the cochlea
The vestibular and cochlear branches merge and together enter cranial cavity through internal auditory canal and travel to junction of the pons and the medulla oblongata