LEC54: Cranial Nerves II Flashcards
function of SVE, special visceral efferent, fibers?
fibers innervating muscles derived from a branchial arch
function of SVA, special visceral afferent, fibers?
fibers that deal w/ GUT-RELATED SENSE of head/neck:
1) taste
2) smell
function of SSA, special somatic afferent, fibers?
NON-GUT related to special SENSE fibers of head/neck:
1) vision
2) balance
3) hearing
what kinds of nerve fibers present in head/neck?
both special and general just b/c in head/neck, doesn’t mean it’s ONLY special fibers- also have general
which CN are special sensory nerves?
1) CNI: olfactory
2) CNII: optic
3) CNVII: vestibulocochlear
what is unique about CNI, CNII?
CNI, olfactory & CNII, optic ARE NOT REALLY NERVES;
nerve must come from a nucleus, go to effector organ, or have sensory ganglia somewhere;
these are actually BRAIN TRACTS
fiber type in CNI, olfactory n? fxn?
SVA ONLY
helps w/ flavor detection by bringing in air
fiber type of CNII, optic n? fxn?
SSA ONLY
nerve of vision
transmits info from retina > brain
function and significance of central artery of the retina?
an END ARTERY w/ NO collaterals
when lose this, lose vision
fiber type of CNVII, vestibulocochlear n? fxn?
SSA only
balance!
vestibular and auditory systems
which CN are myotomal?
1) CNIII, oculomotor
2) CNIV, trochlear
3) CNVI, abducens
4) CNXII, hypoglossal
derivation of myotomal CNs?
somites
what fiber type for all myotomal CN?
GSE
fiber types/fxn of CNIII, occulomotor?
GSE & GVE-autonomics
what do autonomics of CNIII do?
preganglionic parasympathetics, do pupillary constriction
location of CNVI, abducens? susceptibility therein?
lies on clivus bone
v susceptible to pontine tumors
which CN is big motor nerve of tongue?
CNXII, hypoglossal
which CN are branchioneric?
1) CNV: trigeminal
2) CNVII: facial
3) CNIX: glossopharyngeal
4) CNX: vagus
5) CNXI: spinal accessory n
* branchioneric = derived from branchial arches, so have to do w/ neural crest cells*
muscle type related to branchioneric nerves?
skeletal
what is most widespread nerve in the head?
CNV, trigeminal
fiber types for CNV, trigeminal
SVE, GSA
(mainly GSA)
divisions of trigeminal n?
1) opthalmic
2) maxillary
3) mandibular
what controls ability to stick out tongue?
CNV, trigeminal’s GSA fibers
what does CNV, trigeminal, innervate?
1) muscles of mastication
2) muscles of tongue
3) corneal reflex
4) facial sensory innervation
5) mucosa of inernal paranasal sinuses
which divisions of CNV, trigeminal n innervate which parts of face?
what is trigeminal neuralgia?
aka tic douboureaux
usu limited to 1 division of trigeminal on 1 side
extremely painful
fiber types for CNVII, facial n
1) SVE
2) GSA - swatch near auricle
3) SVA - taste!
4) GVE
what is chorda tympani?
nerve that originates in taste buds in front of tongue; runs through middle ear; carries taste messages to brain
joins CNVII (facial n) inside facial canal
therefore facial n, CNVII, carries taste
fiber types of CN IX, glossopharyngeal n?
1) SVE
2) GSA
3) SVA
4) GVE
5) **GVA - **coming back from pharynx
endodermal
*5 fiber types here - greater # found in any CN!*
fiber types of CN X, vagus n
1) SVE
2) GSA
3) SVA
4) GVE
5) GVA
* *5 fiber types, like CN IX!* *
what is cricothyroid m? what supplies it?
muscle of larynx
CNX, vagus n supplies it
fiber types for CN XI, spinal accessory n? structure of CN XI?
SVE
1) cranial root
2) spinal root
distribution of cranial root of CN XI, spinal accessory n? fiber type?
1) goes into CNX, vagus
2) distributed in recurrent laryngeal n
SVE fibers
distribution of spinal root of CN XI, spinal accessory n?
fiber type?
what does it innervate?
1) goes into vagus, CN X
2) comes out as own nerve, spinal accessory n
SVE fibers
innervates trapezius, sternocleidomastoid mm
what do CN IX and CN X share? what is their relationship?
4 brain stem nuclei
are very tight nerves
is there a correlation btwn nerve deafness and nerve balance features? why/why not?
no
b/c vestibular and cochlear nerves come from diff pts on brain stem
major motor innervator of tongue?
CN XII, hypoglossal n
where does thyroid come from?
foramen cecum
what is secondary motor innervator of the tongue?
palatoglossas n, from CNX, XI
what is anterior 2/3 of tongue covered in?
ectoderm
what embryonic tissue type is posterior 1/3 of tongue derived from?
endoderm
what provides general sensation to anterior 2/3 of tongue?
GSA from CN V
what provides taste for anterior 2/3 of tongue?
SVA from CN VII
chorda tympany
what fiber type & from which nerve provides sensory innervation to posterior 1/3 of tongue?
GVA by CN IX
GVA not GSA since endodermally derived
what fiber type & from which nerve carry taste for posterior 1/3 of tongue?
SVA, CN IX, glossopharyngeal
which CN carries taste sensation for epiglottis?
CN X
what is main sensory nerve for gag reflex?
CN IX, glossopharyngeal n
