Cranial Nerves

Question 1

CN I
longest or shortest CN?
function
modality

Answer 1

shortest CN
olfactory nerve
function: smell; detects food through odiferous molecules
SVS (special visceral sensory)

Question 1

damage to CN I causes

Answer 1

anosmia (inability to smell)
parosmia (distortion to smell or taste)

Question 2

CN II
modality
part of what system
function

Answer 2

optic nerve
SSS: special somatic sensory
part of visual sensory system
transmits signals generated by photoreceptors of retina

Question 3

what are 2 reflexes of CN II?

Answer 3

light reflex (constricts pupils)
accommodation reflex (adjusts thickness of lens for NEAR focusing)

Question 4

CN III
modality and function
modulates what reflex

Answer 4

oculomotor nerve
GSM general somatic motor (skeletal muscles) - moves extrinsic eye muscles
GVM general viseral motor (smooth muscles) - pupil sphincter and cilliary muscle
modulates accomodation reflex

Question 5

damage to CN III results in]
how to exam damage

Answer 5

damage to globe causing double vision or ptosis
tested by having eye follow moving object

Question 6

ptosis

Answer 6

eye rotated down and out with a fixed, dilated pupil

Question 7

CN IV
modality
smallest/biggest and longest/shortest nerve?
function

Answer 7

trochlear nerve
GSM- general somatic motor
smallest & longest oculomotor nerve
function: superior oblique (moves eye down & medially)

Question 8

damage to CN IV results in

Answer 8

diplopia - double vision

Question 9

CN V
function
smallest/largest nerve?
modality
divisions (3)

Answer 9

function: sensation to scalp, forehead, nose, sinus, & muscles of mastication
largest nerve
3 divisions: opthalmic, maxillary, mandibular
GSS- general somatic sensory

Question 10

CN VI
function (mention specific muscle_
originates from what brain structure
modality

Answer 10

abducens nerve
function: ctrls lateral rectus muscle (outward movement of eye)
originates from pons
GSM - general somatic motor

Question 11

damage to CN VI

Answer 11

inward deviation (adduction) of eye

Question 12

CN VII
modalities & functions (4)

Answer 12

facial nerve
1. General somatic sensory: sens. to ext. ear
2. Special visceral sensory: taste
3. Special visceral motor: muscles of facial expr.
4. General visceral motor: glands

Question 13

damage to CN VII results in
tested by

Answer 13

bells palsy - idiopathic (usually) temporary facial paralysis
tested by: asking pt to make expression and test for symmetry

Question 14

CN VIII
modality
function

Answer 14

vestibulocochlear nerve
SSS- special somatic sensation
funct : hearing & balance

Question 15

damage to CN VIII results in
pathologies of CN VIII

Answer 15

damage to cochlear nerve = partial/complete deafness
pathologies: vertigo, loss of equilib., nystagmus

Question 16

nystagmus

Answer 16

rapid, involuntary eye movement

Question 17

CN IX
innervates ______
modalities and brief description

Answer 17

glossopharyngeal nerve
innervates stylopharyngeous of pharynx
GSS- posterior pt of tongue & ear
GVS- carotid body & sinus
SVS- taste from posterior pt of tongue
GVM- parotid gland
SVM- stylopharyngeus

Question 18

damage to CN IX results in

Answer 18

abscence of gag reflex
reduced taste to bitter/sour
difficulty swallowing

Question 19

CN X
innervates ____
longest/shortest cranial nerve
component of which pt of nervous system

Answer 19

innervates muscles of phonation
longest cranial nerve
main component of PNS

Question 20

modalities of CN X

Answer 20

GSS- ext. ear, larynx, pharynx
GVS- sensation of organs in abd/thoracic cavities
SVS- taste signals
GVM- cardiac muscle & parastalsis
SVM- pharynx/larynx (phonation and swallowing

Question 21

which cranial nerve is responsible for reducing resting heart rate?
what medication can reduce heart rate?

Answer 21

CN X - vagus nerve
beta blockers

Question 22

CN XI
modalities and function
what are its 2 roots?

Answer 22

accessory nerve
GSM- trapezius (shrug shoulders) & sternocleidomastoid (turn head)
2 roots: cranial and spinal

Question 23

CN XII
modality
ex of voluntary and involuntary function
clinical examanition

Answer 23

hypoglossal nerve
GSM- voluntary and involuntary muscles of tongue
voluntary (speech, eating) & invol (clearing saliva)
clin exam: ask pt to put tongue against cheek