cranial nerves Flashcards
the cranial nerves come
directly from the brain or brain stem
how many cranial nerves
12
CN I
olfactory- sensory
CN II
optic- sensory
CN III
oculomotor
inv superior rectus, inferior rectus, medial rectus, inferior oblique, levator palpebral
parasympathetic- from edinger-westphal nucleus to sphincter pupillae, ciliary muscle
parasympathetic for CN III
from edinger-westphal nucleus to sphincter pupillae, ciliary muscle
CN IV
trochlear
innervates superior oblique muscle
look down/inward
CN VI
abducens
innervates lateral rectus muscle
move eyes side to side
CN V
trigeminal- motor/sensory
“dentist’s” nerve
branches of trigeminal
ophthalmic, maxillary, mandibular
CN VII
facial- motor/sensory
muscles of facial expressions
innervates posterior digastric
sensory external ear and taste anterior 2/3 of tongue
parasympathetic fibers of facial nerve to
lacrimal gland, submandibular, and sublingual gland
CN VIII
vestibulocochlear (auditory)- sensory
innervates inner ear
for hearing, equilibrium, balance
CN IX
glossopharyngeal- motor and sensory
parasympathetic innervation to parotid
innervates stylopharyngess muscle
active in gag reflex- elevates soft palate
what cranial nerve is active in gag reflex
glossopharyngeal (CN IX)
vagus (CN X)
CN X
vagus- motor, sensory
innervates muscles of pharynx and larynx, thoracic and abdominal viscera
involved in gag reflex and swallowing
CN XI
spinal accessory- motor
innervates muscles of pharynx (cranial part and travel with vagus), trapezius (upper), SCM
shrug shoulders, turn head side to side
what cranial nerve has unique origin from spinal cord
spinal accessory (CN XI)
CN XII
hypoglossal- motor
innervate genioglossus, hyoglossus and styloglossus of tongue, plus intrinsic muscles of tongue
assess speech, stick tongue out, move side to side
when does CN screening need to be done
when there is OFP that cannot be localized
parts of ANS
parasympathetic, sympathetic, enteric considered 3rd part (regulates digestion)
2 neuron systems of ANS
preganglionic (myelinated) and postganglionic (unmyelinated)
neurotransmitters of ANS
norepinephrine (postsynaptic)
acetylcholine (presynaptic)
sympathetic NS known as
fight or flight
parasympathetic NS known as
rest and digest
enteric system-major neurotransmission is
Ach, nitric oxide, serotonin
hypothalamus exerts control over
ANS and helps maintain homeostasis
base level of ANS
tone
is ANS always active
yes
sympathetic NS nerves originate in
spinal column between T1 and L2, preganglionic
sympathetic NS pass into
sympathetic chain on each side of spinal column
sympathetic NS nerves leave ganglia as
postganglionic or may travel up or down sympathetic chain
sympathetic NS nerve may pass back into
spinal nerves at all levels, mostly C fibers
what percent of skeletal nerves are sympathetic fibers
8%
sympathetically maintained OFP involves
sphenopalatine ganglion associated with injury to V2 of CN V, related to vascular heads and facial neuralgia
involves stellate ganglion, most common post herpetic neuralgia
parasympathetic distribution
CN III Occulomotor
CN VII Facial
CN IX Glossopharyngeal
CN X Vagus
parasympathetic- preganglionic fibers go to
the structures being targetted
parasympathetic- post ganglionic neurons are in
wall of targeted structure- 1mm to few cm long
what percent of all nerve fibers in CN X (vagus)
75%
parasympathetic CN- CN III Occulomotor
to pupillary sphincters and ciliary muscles of the eye
parasympathetic CN- CN VIII Facial
to lacrimal, nasal and submandibular glands
parasympathetic CN- CN IX Glossopharyngeal
to parotid gland
parasympathetic CN- CN X Vagus
to thoracic and abdominal regions
