Cranial Nerves

Question 1

cranial nerves overview

Answer 1

• 12 pairs
• attached to brain
• can be sensory, motor, or mixed
• control head/neck/ face (except vagus nerve)

Question 2

sensory nerves

Answer 2

long dendrites of only sensory neurons

Question 3

motor nerves

Answer 3

long axons of only motor neurons

Question 4

mixed nerves

Answer 4

long dendrites and long axons

Question 5

special sensory nerves

Answer 5

carry information for sight, smell, hearing, or balance

Question 6

CN I

Answer 6

olfactory nerve

• special sensory nerve –> sense of smell
• originates in olfactory epithelium
• terminates in olfactory bulbs
• attached to cerebrum (unlike all others, which are attached to brain stem)

Question 7

CN II

Answer 7

optic nerve

• special sensory nerve –> sense of sight
• originates in retina of each eye, crosses at optic chiasm
• synapses in thalamus, which sends info to visual cortex of occipital lobe

Question 8

CN III

Answer 8

oculomotor nerve

• motor nerve –> eye movement + pupil dilation
• somatic motor movement (muscles)
• visceral motor movement (pupils)

Question 9

purpose of pupil dilation

Answer 9

controls the amount of light let into the eye

Question 10

CN IV

Answer 10

trochlear nerve

• motor nerve: innervates superior oblique muscle –> eye movement
• somatic motor movement (muscles)

Question 11

CN V

Answer 11

trigeminal nerve

• mixed nerve –> mastication, sensation of face/nose/mouth
• 3 branches

Question 12

opthalmic branch of trigeminal nerve

Answer 12

• entirely sensory

- receives info from skin around forehead, eyebrows, upper part of nose

Question 13

maxillary branch of trigeminal nerve

Answer 13

• entirely sensory

- receives info from lower eyelids, upper lip/gums, part of pharynx

Question 14

mandibulary branch of trigeminal nerve

Answer 14

• sensory –> receives info from lower lip/gums, teeth, tongue (except taste)
• motor –> innervates muscles of mastication

Question 15

CN VI

Answer 15

abducens nerve

• motor nerve –> abduction of eye (outward/lateral mvmt)
• innervates lateral rectus muscles

Question 16

CN VII

Answer 16

facial nerve

• mixed nerve
• responsible for facial expressions, sensation of tongue, taste (anterior tongue)
• visceral motor functions –> controls tear glands, nasal mucous glands

Question 17

CN VIII

Answer 17

vestibulocochlear nerve

• special sensory nerve –> hearing + balance
• 2 branches
• travels via internal acoustic meatus in temporal bone

Question 18

vestibular branch of vestibulocochlear nerve

Answer 18

responsible for balance and equilibrium

Question 19

cochlear branch of vestibulocochlear nerve

Answer 19

responsible for sense of hearing

Question 20

CN IX

Answer 20

glossopharyngeal nerve

• mixed nerve
• motor –> innervates swallowing muscles
• sensory –> taste (posterior tongue)
• visceral motor functions –> controls parotid salivary glands

Question 21

CN X

Answer 21

vagus nerve

• mixed nerve
• responsible for digestion, heart rt regulation, sensation of digestive tract
• spreads out widely in abdomen

Question 22

CN XI

Answer 22

accessory nerve

• motor nerve
• controls muscles involved in head rotation, mvmt of upper shoulders

Question 23

CN XII

Answer 23

hypoglossal nerve

• motor nerve
• responsible for voluntary tongue movements