cranial nerves Flashcards
(121 cards)
the cranial nerve nuclei
- each nucleus has a single function
- location of nucleus in brain stem follows organization of neural tube
somatic efferent column includes what 4 nuclei?
- hyoglossal nucleus
- abducens nucleus
- trochlear nucleus
- oculomotor nuclei
somatic efferent column nuclei order of ascending the brain stem
caudal > rostral
hypoglossal > abducens > trochlear > oculomotor
hypoglossal nucleus function
- controls intrinsic and extrinsic muscles of the tongue
where do the hypoglossal nucleus axons exit?
between the pyramid and inferior olive and join in to make CN XII (12)
signs and symptoms of hypoglossal nerve lesion
- paralysis of ipsilateral half of the tongue
- on protrusion, tongue deviates to side of lesion (unopposed action of genioglossus muscle)
- atrophy and fasciculations
hypoglossal nucleus location and shape
- in the medulla
- spherical/dome shaped
- alpha motor neurons innervating the tongue
abducens nucleus location and shape
- in caudal pons
- spherical
what does the abducens nucleus control?
- lateral rectus muscle
where does the abducens nucleus axons exit?
attached at junction of pons and medulla and in CN VI (6)
signs and symptoms of lesion on CN VI (abducens nucleus)
- medial strabismus
- diplopia
- inability to abduct eye
trochlear nucleus location
caudal midbrain
what does the trochlear nucleus control?
- superior oblique muscles
where do the trochlear nucleus axons exit?
- CN IV (4)
- CN IV leaves on dorsal side of brain stem and decussates
signs and symptoms of lesion on CN IV (trochlear)
- limitation of downward gaze when looking medially
- postural adjustments
oculomotor nuclei location
rostral midbrain
what does the oculomotor complex contain? what do they control?
- subnuclei that control medial rectus, superior rectus, inferior rectus, and inferior oblique muscles
- subnucleus that controls levator palpebrae superior
where do the oculomotor complex axons exit?
from interpeduncular fossa into CN III (3)
signs and symptoms of a lesion on CN III (oculomotor complex)
- eye is down and out
- ptosis (drooping of eyelid)
general visceral efferent column includes…
- dorsal motor nucleus of the vagus
- salivatory nuclei (inferior and superior)
- Edinger-westphal nucleus
location of dorsal motor nucleus of X
in medulla, ventral to 4th ventricle
what is the dorsal motor nucleus of X and what does it do?
- preganglionic parasympathetic fibers
- supply heart, lungs, stomach, and intestine
where do the dorsal motor nucleus of X axons exit and synapse?
exit: CN X
synapse: in parasympathetic ganglia of organs innervated
inferior salivatory nucleus location
dorsal pons