Cranial nerves Flashcards
all the nuclei are located in the brainstem except CN
I, II, XI
CN I, II, VIII are devoted to
special sensory input
purely motor
III, IV, VI, XI, XII
purely sensory
I, II, VIII
mixed
V, VII, IX, X
CN III, IX, and X carry
sympathetic fibers
CN located in diencephalon
I, II
CN located in midbrain
III and IV
CN located in pons
V, VI VII VIII
CN located in medulla
IX, X, XI, XII
innervates striated muscles that are somite derivatives
somatic efferent (GSE) CN III IV VI
innervate branchial arches derivatives
SVE/ branchial efferent V, VII, IX, X, XI
preganglionic parasympathetic components of cranial
division
GVE
convey sensation from the alimentary tract, heart, vessels
and lungs by way of nerves IX and X.
GVA IX, X
convey sensation from the skin and the mucous membranes
of the head (mainly CN V)
GSA
found in CN I (smell), CN II (vision) and CN VIII (hearing and
equilibrium)
SSA
most primitive of all CN
CN I
CN I does not pass thru
thalamus
2 parts of CN I
olfactory bulb
olfactory stalk
olfactory stalk carries
afferent axons
olfactory bulb lies above the
cribriform plate
CN I terminates in
primary olfactory cortex and entorhinal cortex
CNI pathway
receptor cells - olfactory nerves - O bulb, O stalk, anterior olfactory nucleus
olfactory cells are surrounded by _______ with bowman’s glands that secrete _____
sustentacular cells; mucus
_____ are the ones that respond to olfactory chemical stimuli
olfactory cilia
2 type of interneurons of olfacotry bulb
periglomerular cells
granule cells
receives signals from olfactory sensory neurons an
centrifugal fibers
periglomerular cells
most numerous interneurons
granule cells
most characteristic feature of the
olfactory bulb in all vertebrates where these elements interact
olfactory glomeruli
(SYNAPTIC TRIAD):
a. olfactory axon (input fiber)
b. mitral and tufted cells (principal neurons)
c. periglomerular cell (intrinsic neuron)
the olfactory tract/ stalk consists of central axons of the ________ of the
bulb and some centrifugal fibers from the opposite olfactory
bulb
mitral and tufted cells
regulate information flow between nearly every region where
odor information processing occurs.
Anterior Olfactory Nucleus
center of highest visual acuity
fovea
fovea is the center of
highest visual acuity
CN II optic nerve conveys visual impulses from the
retina
the optic nerve passes through the _____ to the orbit
optic papilla
the optic nerve becomes the optic tract after passing through the
optic chiasm
rods are for _______ vision
night (scotopic)
cones are for ____ vision
day (photopic)
CN III oculomotor nerve nucleus is located at
midbrain
CN III controls
eye movement, pupillary constriction
axons of oculomotor nucleus supplies all extraocular muscles
muscles except:
Superior oblique (CN IV) and lateral rectus (CN V)
the superior oblique muscle intort the eye when the eye is _____
abducted
the superior oblique muscle _____ the eye when the eye is adducted
depress
the only crossed cranial nerve
trochlear
CN IV is the only one to leave the ____
posterior surface of the brainstem
CN IV Enters the ________ below CN III and exits the ______ to innervate the superior oblique
cavernous sinus; superior
orbital fissure
nerve of the 1st pharyngeal arch
CN V
3 div of CN V
opthalmic
maxillary
mandibular
the sensory root of CN V arises from the ________ which lies in the _______ lateral to the cavernous sinus
Gasserian ganglion; meckel’s cavity
the opthalmic division enters the cranium through the
superior orbital fissure
maxillary div enters through the
foramen rotundum
mandibular div sonsory enters through the
foramen ovale
abducens nerve is pure _____
GSE nerve
CN VI innervates ______ which abduct the eye
lateral rectus
most frequently injured CN
CN VI
the abducens has the ____________ among CN
longest intracranial course
where abducent nerve hangs)
clivus
increased ICP leads to______ because _______-
bilateral nerve palsy; clivus pushed downward
the internuclear neurons of CN VI innervates
medial rectus
the ______ sends parasympathetic preganglionic
fibers to the _____ to innervate the _____ and via the chord tympani nerve to the submandibular and sublingual
nervus intermedius; pterygopalatine ganglion; lacrimal
gland
internal auditory meatus is the passageway for
CN VII and VIII
CN VII exits through the
styloid foramen
CN VII innervates the
muscle for facial expression
CN VIII arises from the _____ in the labyrinth of the inner ear
spiral and vestibular ganglion
CN VIII is confined to the
temporal bone
The primary auditory cortex (areas 41 and 42) includes the _______
on the upper surface of the superior temporal
gyrus.
gyrus of Heschl
CN IX contains branchial efferents from the ________ to the _________
nucleus ambiguous to the stylopharyngeus muscle
CN IX supplies general sensation to the
pharynx
soft palate
posterior 1/3 of tongue
CN XI innervates
head and shoulder movement and innervation of laryngeal muscles
2 components of CN XI
cranial
spinal
cranial component of CN XI form the
internal branches
spinal component of CN XI form the
external branches
the cranial component of CN xi innervates ________ and is regarded as a
component
branchiometric musculature; special visceral efferect (SVE)
the spinal component of CN XI innervates the
ipsilateral sternocleidomastoid muscle and
upper parts of the trapezius muscle.
Paralysis of the upper part of the trapezius muscle – results
shoulder drop
CN XII mediates
tongue movement
CN XII innervates
ipsilateral half of the tongue
CN XII nucleus is located
internal to trigonum hypoglossi
CN XII nucleus is surrounded by gray matter which contains
perihypoglossal nuclei
nucleus intercalatus is between
hypoglossal nucleus and motor nucleus of vagus
normal reflex consisting of retching; may be produced by
touching the soft palate in the back of the mouth
gag reflex
the movement of the eyes as a unit in the opposite direction
when the head is moved
doll’s eye phenomenon