Cranial Nerves (minus V and VII) Flashcards
What ar the cranial nerve names and their brain associations?
Forebrain: CN I (olfactory); CN II (optic)
Midbrain: CN III (oculomotor) CN IV (trochlear)
Pons: CN V (trigeminal) CN VI (abducens) CN VII (facial) CN VIII (vestibulocochlear)
Medulla oblongata: CN IX (glossopharyngeal) CN X (vagus) CN XI (accessory) CN XII (hypoglossal)
Which ones have parasympathetic fibers? What kind? Where do they synapse?
CN III (oculomotor) to ciliary ganglion
CN VII (facial) to submandibular and pterygopalatine
CN IX (glossopharyngeal) to otic
CN X (vagus) to the lower body
all have pregangionic parasympathetic fibers
- The cell bodies of all general sensory neurons are located in ganglia of which cranial nerves?
- These ganglia are analogous to the _____.
- What kind of neurons are they?
- Which ones have taste neurons?
- (V) Trigeminal nerve
(VII) Facial nerve*
(IX) Glossopharyngeal nerve*
(X) Vagus nerve * - dorsal root ganglia of the spinal cord
- (pseudounipolar neurons)
- *have taste
Where are motor neurons located?
What kind of neurons are they?
in all cranial nerves in NUCLEI in the brainstem (analogous to the ventral horn of the spinal cord)
multipolar neurons
The _____ innervate all of the structures derived from the branchial arches. They are?
Skeletal muscles derived from branchial arches are said to be innervated by ____ fibers, as opposed to all other muscles which are innervated by ____ fibers.
branchiomeric cranial nerves
Trigeminal nerve (V) Branchial arch 1 Facial nerve (VII) - Branchial arch 2 Glossopharyngeal nerve (IX) - Branchial arch 3 Vagus nerve (X) - Branchial arches 4 - 6 Accessory nerve (XI) - Branchial arches beyond arch 6?
**so all the ones with general sensor PLUS accessory nerve
branchial motor or special visceral efferent; general somatic efferent
This nerve supplies a branchial arch, but has no general sensory neurons in its ganglia.
Accessory (CN XI) supplies branchial arches >6
These nerves have both taste and general sensory neurons AND supply branchial arches.
(VII) Facial nerve (2)
(IX) Glossopharyngeal nerve (3)
(X) Vagus nerve (4-6)
What are the ocular muscles and what supplies them?
SO4 LR6 AR3
superior oblique eye muscle - CN IV (trochlear)
lateral rectus eye - CN VI (abductens)
all the rest - CN III (occulomotor)
Levator palpebrae superioris; Superior, Medial, and Inferior rectus eye muscle; Inferior oblique eye muscle
Trace the course of CN III, pay close attention to the parasympathetic fibers.
Oculomotor nerve:
emerges from ventral aspect of midbrain
proceeds through lateral wall of cavernous sinus
enters orbit thorugh superior orbital fissure (with CN IV and VI)
divides into superior and inferior division
parasymp component is in inferior division and leaves as parasympathetic (motor) root of the ciliary ganglion; goes to ciliary ganglion and sypanses; postgang fibers travel as short ciliary nerves to eyeball
Describe control of the pupil.
Parasympathetic: short ciliary nerves from ciliary ganglion supply ciliary muscle (change lense for near vision) and sphincter of the pupil (controls light)
Sympathetic: dilator of the pupil is controled by postgang fibers from superior cervical ganglion
Describe CN VIII.
Vestibulocochlear nerve
has two divisions: vesibular (sensory re: balance and equilibirium) and cochlear (sensory re: hearing)
enters internal acoustic meatus with CN VII (facial)
What kind of fibers does CN IX have?
Glossopharyngeal
- branchial motor / special visceral
- pregang. parasym
- visceral sensory (carotid body/sinus)
- special sensory (taste)
- general sensory
What are the branches of CN IX?
- tympanic
- carotid nerve (carotid sinus/bodies)
- motor to stylopharyngeus muscle (only muscle)
- pharyngeal and tonsillar branches (sensory)
- lingual branch (sensory/taste to posterior 1/3 of tongue)
Describe the course of CN IX out of the skull.
- emerges from medulla oblongata from post olivary sulcus
- has two sensory ganglia (sup, inf) in jugular foramen
- exits skull in jugular foramen with CN X, XI
What is an example of referred pain via CN IX?
How do you test if there is a lesion of CN IX? Why not a gag reflex test?
middle ear pain from tonsillitis
taste test in posterior 1/3 of tongue; you can try to use gag refelx by stroking posterior 1/3 of tongue, if vagus is still in tact. however, if vagus is also compromised, IX may induce gag reflex but pharyngeal muscles are mostly innervated by vagus so they will not be functional, thus is there no gag b/c afferent or efferent is faulty?