Block 3 - Cranial Nerves

Question 1

cranial nerves are either what?

Answer 1

afferent (neurons only)

mixed (some combination of afferent (sensory) and efferent (motor))

Question 2

mixed nerves are

Answer 2

primarily motor or sensory

Question 3

two types of cranial nerves contain ONLY sensory neurons

Answer 3

cranial nerve I (optic)

cranial nerve II (olfactory)

Question 4

cranial nerve VIII (vestibulocochlear) contains

Answer 4

predominately sensory but has motor function present

Question 5

what are the “sensory” nerves

Answer 5

cranial nerve I, II, VIII

Question 6

no cranial nerves are exclusively

Answer 6

motor throughout their entire length

Question 7

cranial nerves III, IV, VI, XI, XII are

Answer 7

predominately motor neurons

Question 8

cranial nerves V, VII, IX, and X are

Answer 8

mixed cranial nerves

Question 9

cranial nerves V, VII, IX and X contain

Answer 9

both sensory and motor neurons

Question 10

cranial nerves IV and VI innervate

what is unique

Answer 10

trochlear (superior oblique) and abducens (lateral rectus)(eye)

both muscles of extrinsic muscles of the eye

Question 11

the trochlear and abducens nerves are

Answer 11

primarily motor with proprioreception of its muscle being its sensory function

Question 12

what do all motor cranial nerves possess

Answer 12

neurons that INNERVATE somatic (skeletal) muscles

Question 13

what motor cranial nerves have autonomic motor axons

Answer 13

III (oculomotor), VII (facial), IX (glossopharyngeal), X (vagus)

Question 14

what are the autonomic axons a part of

Answer 14

parasympathetic division, and innervate glands, smooth muscles, and cardiac muscles

Question 15

what does “in-situ” mean

Answer 15

in place

Question 16

describe the olfactory nerves

Answer 16

Cranial Nerve I
entirely sensory
sense of smell
olfactory bulb and tract are NOT in CN I

Question 17

Describe the receptors of the olfactory nerves

Answer 17

receptors are bipolar
axons of receptors extend thru the cribiform plate of the ethmoid
the bundles are the olfactory nerve

Question 18

when a patient cannot perceive a common non-offensive smell

Answer 18

anosmia

Question 19

describe the optic nerves

Answer 19

Cranial Nerve II
entirely sensory
myelinated axons

Question 20

what are light sensitive cells

Answer 20

optic (cranial nerve II) - rods and cons in retina

Question 21

describe signal pathway of rods and cones

Answer 21

sense light –> bipolar cells –> ganglion cells in retina

Question 22

what forms the optic tract

Answer 22

axons of the ganglion cells form the optic nerve which then form the optic tract

Question 23

when a patient cannot utilize/perceive peripheral vision

Answer 23

damage to optic nerve (CN II)

Question 24

describe cranial nerve III

Answer 24

oculomotor
mainly MOTOR
controls extrinsic eye muscles not innervated by IV, VI
innervates intrinsic eye muscles: ciliary muscle (on lens) sphincter pupillae (iris)

Question 25

what type of innervation does occulomotor possess

Answer 25

parasympathetic innervation to intrinsic eye muscles

Question 26

the occulomotor innervates the muscle of the upper eyelid

Answer 26

levator palpebrae superioris

Question 27

patient test of oculomotor

Answer 27

pupils constrict when light is shined in only one eye

Question 28

describe trochlear

Answer 28

Cranial Nerve IV mainly motor smallest of cranial nerves innervates superior oblique muscle of eye

Question 29

what cranial nerve arise from the posterior aspect of the brain stem

Answer 29

trochlear

Question 30

what is the trochlea

Answer 30

pulley-like loop that the superior oblique muscle passes thru

Question 31

what moves the eyeball inferiorly and laterally

Answer 31

superior oblique

Question 32

test for cranial nerves III, IV, VI

Answer 32

following moving object with the eyes

Question 33

describe trigeminal

Answer 33

cranial nerve V mixed nerve largest of all cranial nerves emerges from pons isolated from other CNs

Question 34

what does trigeminal provide

Answer 34

sensory to face, head, and ANTERIOR 2/3 of tongue (TACTILE) motor for chewing movements function is mastication, facial sensation

Question 35

what are the two trigeminal roots

Answer 35

smaller motor root for mastication | larger sensory root: ophthalmic nerve, maxillary nerve, mandibular nerve

Question 36

what are the three sub nerves of the CN V?

Answer 36

opththalmic nerve (v1), maxillary nerve (v2), mandibular (v3)

Question 37

physical exam for trigemial

Answer 37

assessment of motor function; bite down while feeling the masseter muscle, then to have the patient attempt to open their mouth against resistance applied by the examiner

Question 38

corneal relfex tests for

Answer 38

ophthalmic nerve (CNV1)

Question 39

describe dermatome

Answer 39

area of skin that is mainly supplied by afferent nerve fibers from a single dorsal root of spinal nerve which forms a part of a spinal nerve.

Question 40

cranial nerve V is the what for the skin of face and scalp

Answer 40

dermatome

Question 41

describe CN VI

Answer 41

abducens | lateral rectus muscles - lateral movement