Cranial Nerves (non AI)

GSA is what type of fiber and utilize what type of neuron

peripheral sensory; pseudounipolar

GSE is what type of fiber and utilize what type of neuron system

motor (voluntary); one neuron system

GVA is what type of fiber and utilize what type of neuron

sensory (body); pseudounipolar

GVE is what type of fiber and utilize what type of neuron system

motor (involuntary); two neuron

SSA is what type of fiber

special sensory afferent (vision, olfaction, taste, balance, hearing)

somatosensory = ____ fiber

branchiomoter = ____ fiber

viscerosensory = ____ fiber

visceromoter = _____ fiber

special sensory = _____ fiber

GSA, GSE, GVA, GVE, SSA

which cranial nerves are associated with the forebrain

CNI, CNII (olfactory, optic)

which cranial nerves are associated with the Midbrain

CNIII, CNIV (oculomotor, trochlear)

which cranial nerves are associated with the pons

CNV, CNVI, CNVII (trigeminal, abducens, facial)

which cranial nerve is associated with the pons and medulla

CNVIII (vestibularcochlear)

Which cranial nerves are associated with the medulla

CN VIII, CN IX, CNX, CNXI, CNXII (vestibulocochlear, glossopharyngeal, vagus, spinal accessory, hypoglossal)

which cranial nerves are associated with the medulla and spinal cord

CN XI (Spinal accessory)

What is the functional modality of CN I

SSA, olfaction/smell

____ cell acons form the olfactory tract

Mitral

Olfactory mucosa houses bipolar neurons in the nasal cavity that project through the cribriform plate of the ethmoid bone to synapse where

olfactory bulb

Hyposmia is a decrease in the sense of smell
Anosmia is the complete loss of smell
what typically causes these conditions

inflammation of the mucosal membrane, can be assoc. with age

What is the functional modality of the optic nerve

SSA-vision

What is the pathway for CN I

forebrain to the olfactory mucosa

what is the pathway for CN II

forebrain → optic canal → orbit

What are the functional modality of CN III

GSE, GVE

Explain the GSE modality of CN III

superior division innervates the levator palpebrae superioris & superior rectus; inferior division does the inferior rectus, inferior oblique, and medial rectus

Explain the GVE modality of CN III

preganglionic parasympathetic fibers synapes in the ciliary ganglia these fibers go to the ciliary muscle and the sphincter pupillae

what is the pathway of CN III

midbrain → cavernous sinus → superior orbital fissure → orbit

What is the pathway of CNIV

midbrain→ run posteriorally then anteriorally to the superior oblique

What is the functional modality of CNIV

GSE- sensory

What is the functional modality of CN VI

GSE- sensory

What is the path of the abducens (VI)

pons → runs anteriorly to innervate the lateral rectus

The superior rectus (CN III) allows for what eye movements

Up & In

The inferior rectus (CN III) allows for what eye movements

Down & Out

The inferior oblique (CN III) allows for what eye movements

Up and Out

Medial rectus (CN III) allows for what eye movements

Medial (adduction)

Superior oblique (CN IV) allows for what eye movements

Down & Out

Lateral rectus (CNIV) allows for what eye movements

lateral (abduction)

The oculomoter (CN III) nerve splits into

a superior and inferior division

what happens in the superior division of CN III split

innervates the lev. palprebrae superioris (GSE- voluntary motor)

what happens in the inferior division of CN III split

innervates the ciliary muscles and pupillary sphincter (GVE- involuntary movement) → bifurcates and innervates the medial rectus, inferior rectus, and inferior oblique (GSE- voluntary movement)

What is CN V (trigeminal) funcational modalities

GSA & GVE

What is the general CN V pathway for GSA

Pons → split into 3 branches → middle cranial fossa → trigeminal ganglion

CN V1 (ophthalmic) goes from the middle cranial fossa through the ______

superior orbital fissure

CN V2 (maxillary) goes from the middle cranial fossa through the ________ and is assoc. with ________

foramen rotundum; pterygopalatine fossa

CN V3 (mandibular) goes from the middle cranial fossa through the ________ and is assoc. with _______

foramen ovale; infratemporal fossa

CN 5 and its branches are the main ______ for the head

sensory nerve

aneurysms in the posterior communicating, posterior cerebral, or superior cerebellar arteries can result in damage of what cranial nerve

CN III (oculomoter)

a patient with limited downward movement of the eye signals damage to what nerve

CN IV (trochlear)

a patient presents with the inability to abduct one of their eyes, which nerve is likley damaged

abducens

The afferent limb of the optic nerve and the efferent limb of the oculomoter nerve work together to achieve what in the eyes

bilateral pupillary constrictions

the corneal blink reflex is a bilateral response that relys on sensory information from ______ and motor information from ________

ophthalmic n (CN V1); facial n (CN VII)

What are the functional modalities of the facial nerve (CN VII)

GSE, GVE, GSA, GVA, SSA (taste)

what is the pathway of the facial nerve (CN VII)

pons → posterior cranial fossa → inernal acoustic meatus (temporal bone) → facial canal → exits via stylomastoid foramen

GSE of CN VII innervate

muscles of facial expression, stapedius, stylohyoid, posterior belly of digastric muscle

GVE of CN VII distribute to what two ganglia

pterygopalatine, submandibular

GVE of CN VII innervate what glands

lacrimal, nasal, palatine, submandibular, and sublingual

all pseudounipolar neuron cell bodies are house where

geniculate ganglion

GSA of CN VII provides sensory information for

posterior ear and internal auditory meatus

GVA of CN VII provides sensory information for

oral and nasal cavities via the greater petrosal nerve

CN VII provides SSA (taste) for

anterior 2/3rd of the tongue via chorda tympani

Inflammation of the facial nerve near the stylomastoid foramen w/ symptoms that can include paralysis of facial expression muscles, inability to close the eye, and difficulty keeping food in the mouth

Bells Palsy

what is a major concern during a parotidectomy

severing a facial nerve branch

what are the functional modalities of CN VIII (vestibulocochlear)

Two SSAs, hearing and balance

What is the pathway for CN VIII

pons & medullar → posterior cranial fossa → internal acoustic meatus (temporal bone) → inner ear

CN VIII has bipolar sensory neurons with cell bodies in what ganglia

vestibular and cochlear

a lesion of the vestibular ganglion presents as what symptoms

vertigo, dizziness/loss of balance

a lesion of the cochlear ganglion presents as what symptoms

hearing loss; tinnitus

CN IX (Glossopharyngeal) functional modalities

GSE, GVE, GSA, GVA, SSA (taste)

CN IX pathway

medulla → posterior cranial fossa → jugular foramen

GSE fibers of CN IX go where

Stylopharyngeus

GVE fiver of CN IX go where

preganglionic parasympathetic fiber that distribute into otic ganglion

once the GVE fibers reach the otic ganglion they then ride with the auriculotemporal nerve to reach what

the parotid gland

GSA of CN IX gas cell bodies in the superior ganglion that provide sensation to what structures

auricle and external auditory meatus

CVA of CN IX cell bodies in the inferior ganglion provide sensation to what structures

tympanic plexus, baroreceptor (carotid sinus)/chemoreceptor (body), pharyngeal plexus, and posterior 1/3 of the tongue

SSA of CN IX does what

provides taste to the posterior 1/3rd of the tongue

CN X functional modalities

GSE, GVE, GSA, GVA, SSA (taste)

CN X pathway

medulla → posterior cranial fossa → jugular foramen

CN X GSE provides motor innervation to

laryngeal & pharyngeal muscles, palatoglossus, soft palate muscles (not tensor veli palatini, V3)

CN X GVE provides parasympathetics motor innervation to

thoracic and abdominal region

CN X GSA provides sensory innervation via what to what structures

cell bodies in superior ganglion; sensation to auricle and external auditory meatus

CN X GVA provides sensory innervation via what to what structures

cell bodies in inferior ganglion; pharyngeal plexus, chemoreceptors in carotid body, laryngeal mucosa, and smooth muscle/glands from abdominal viscera

CN X provides SSA (taste) to what structure

epiglottis

if a patient presents with the absence of taste on the posterior 1/3rd of the tongue and an absent gag reflex on one side, what is the most likely cause

lesion of CN IX (gag reflex absent on the side of the lesion)

Patient presents with a difficulty swallowing, speaking, and elevating the soft palate. You also notice that the uvula is deviated towards one side, what is the most likely cause

lesion of CN X branches

With a lesion of the CN X branches, is the uvula deviating towards the affected or normal side

normal

CN IX provides the _______ info for the gag reflex

sensory

CN X provides the _______ info for the gag reflex

motor

CN XI functional modality

GSE

CN XI pathway

medulla & spinal cord → posterior cranial fossa → jugular foramen

CN XI does motor innervation of

sternocleidomastoid, trapezius

CN XII functional modality

GSE

CN XII pathway

medulla → posterior cranial fossa → hypoglossal canal

CN XII provides motor innervation for

extrinsic and intrinsic muscles of the tongue