Brainstem and cranial nerves

the only nerve that exits dorsally

trochlear nerve (CN IV)

optic nerve?

CN II

CN II?

optic nerve

oculomotor nerve?

CN III

CN III?

oculomotor nerve

trochlear nerve?

CN IV

CN IV?

trochlear nerve

trigeminal nerve?

CN V

CN V?

trigeminal nerve

abducens nerve?

CN VI

CN VI?

abducens nerve

facial nerve?

CN VIII

CN VIII

facial nerve

glossopharyngeal nerve?

CN IX

CN IX?

glossopharyngeal nerve

vagus nerve?

CN X

CN X?

vagus nerve

hypoglossal nerve?

CN XII

CN XII?

hypoglossal nerve

spinal accesory nerve?

CN XI

CN XI?

spinal accessory nerve

CN I Olfactory nerve responsible for

ipsilateral smell

anosmia

loss of smell, associated with aging/dementia

olfaction is the only tract that crosses thru —

thalamus, before cortex

— is the only tract that crosses thru the thalamus

olfaction

axons of mitral cells in olfactory bulb project directly to — — and —

piriform cortex, amygdala (memory/emotion)

CNII optic nerve

axons of retinal ganglion cells

gives visual acuity

light-based responses/perceptions

retinal ganglion cells send their axons from the retina to the — — —, — —, and — —

lateral geniculate nucleus, superior colliculus, pretectal area

lateral geniculate nucleus (LGN)

path for visual info to reach cortex

superior colliculus (SC)

involved in directing eye movements

pretectal area

involved in pupillary eye reflex (and other functions)

what area is involved in pupillary eye reflex

pretectal area

what area is involved in directing eye movements

superior colliculus

what is the path for visual info to reach cortex

lateral geniculate nucleus

the optic chiasm sits right in front of what gland

pituitary gland

if the patient has pituitry issues whats first thing checked

temporal receptive fields

the extrinsic muscles of eye innervated by what 3 nerves

CN III (oculomotor) IV (trochlear) VI (abducens)

adduct

move medially

abduct

move eye temporal

intorsion

rotate upper pole of eye nasally

extorsion

rotate upper pole of eye temporally

yoking

the coordinated complementary movements of both eyes to avoid diplopia

what is the coord complementary movements of both eyes to avoid diplopia

yoking

CN III oculomotor nerve

moves all extraocular muscles (also elevates eyelid) except superior oblique/lateral rectus

parasymp to pupil constrictor/ciliary muscles for near vision

sign of oculomotor palsy

dilated eyes/unable to move/unable to constrict

eyeball drift down and out, ptosis

cranial nerve III does not innervate

lateral rectus, superior oblique

trochlear nerve CN IV

superior oblique, causes depression and intorsion of eye

because the trochlear nerve exits from the back, what are characteristics

extremely thin and long, easily damaged

trochlear palsy

head tilt towards side, eye shoots up towards it

abducens nerve CN VI

lateral rectus, abduction of eye

6th nerve palsy

eye does not go fully to side of lesion

edinger-westphal

parasymp nucleus for pupil

medial longitudinal fasciculus

interconnects eye motor nuclei

crit for yoking eye muscles

MLF syndrome

aka internuclear ophthalmoplegia, lesion in MLF, issues with yoking

anisocoria

condition characterized by an unequal size of the eyes’ pupils

CN V trigeminal nerve

sens of touch, pain, temp, joing pos, vibration of face, moth, anterior 2/3 of tongue, nasal sinuses, meninges

muscles of mastication (jaw) and tensor tympani muscle, mouth anterior 2/3 of tonue/nasal sinuses

trigeminal neuralgia (tic douloureux)

intense pain gen from CNV, ukn cause

pain and temp primary sensory neurons are located in the — — and then project to — — to then join the — —

trigeminal ganglion, Lissauer’s tract, anterolateral system

fine touch synapses on — — — of V, which crosses and joins — —

main sensory nucleus of V, joins medial lemniscus

facial nerve VII functions

facial expression muscles/stapedius muscle/part of digastric muscle

parasymp to lacrimal glands/sublingual/submandibular/all salviary glands except parotid

taste from anterior 2/3 of tongue

sensation from small region near external auditory meatus

facial nerve (VII) stapedius muscles helps

dampen sounds

damage to stapedius muscle causes

hyperacusis

upper motor neuron lesions of the facial muscle nerves tend to spare the top of the face from paralysis. why?

upper facial motor nucleus is bilaterally innervated

if right motor cortex damage, can we raise left eyebrow

yes bc still innervated by other side

anything below the eye is inneervated by

opposite side

muscle groups spared in bell’s palsy

extraocular (CN III, IV, VI)

does bell’s palsy target umn or lmn?

lmn CN VIII

bell’s palsy vs stroke

stoke: full body with neuro signs (can still move eyebrows)

bells: only paralysis of face

what nerve control eyelids

cn III and VII

which nerve closes eye

VIIwh

which nerve opens eye

III

bogorad’s syndrome (crocodile tears syndrome)

motor dyskinesis— instead of making saliva makes tears

vestibulochochlear nerve VIII function

hearing/vestibular

one common cause of vertigo

debris from otoliths settling on hair cells in vestibule

epley maneuver is used for

used to treat paroxysmal positional vertigo

hearing loss in one ear is due to lesions in

nerve level instead of cns

glossopharyngeal nerve IX fucntokn

stylopharyngeus muscle, parasymp to parotid gland, sens from mid ear/external auditory meatus/pharyns/posterior 1/3 of tongue

chemo- and baroreceptors of carotid body

stylopharyngeus muscle

helps to elevate larynx and pharynx

which nerve is resp for gag reflex

CN IX, X

which nerve has no nucleus

glossoparyngeal nerve

nucleus ambiguus

cluster of motor neurons in medulla oblongada responsible for speech and sound production (IX and X)

vagus nerve X functions

motor: pharynx and larynx

parasymp: heart, lungs, digestive tract

sensory: pharynx, meninges, area near auditory meatus

special sens: taste from epiglottis/pharynx, chemo/baroreceptors of aortic arch

how is the CNX damaged

viat intubation damaging the recurrent laryngeal nerve

accessory spinal nerve XI functions

motor control upper shoulders/neck

hypoglossal nerve XII function

intrinsic muscles of tongue

damage to hypoglossal nerve XII does what

tongue points toward lesion

— is the sensory branch of gag reflex and — is motor

CNIX, CNX