Lecture 44 - Cranial Nerves 1 & 2

Question 1

T/F: cranial nerves are classified as part of the peripheral nervous system

Answer 1

TRUE

Question 2

which cranial nerves carry parasympathetic motor fibers?

Answer 2

CN 3, 7, 9, and 10

Question 3

Firulais, a terrier mix, is showing signs of a CNS lesion. He displays a normal response to the menace response test in both eyes, and an absent pupillary light reflex (PLR) in the left eye. You also notice lateral strabismus in the left eye. Tapping on the medial and lateral canthus of the left eye does not elicit a response, nor does manipulating the whiskers on the left side of the maxilla. Pinching the skin on the left side of the mandible also does not elicit a response.

Which cranial nerve(s) are showing deficits in little Firulais?

Answer 3

CN 3 and 5

Question 4

You are presented with a cat whose owner is reporting that she has been coughing and hacking when trying to eat and drink. Testing her gag reflex shows that the reflex is absent. The tongue responds to stimulation and seems to move normally. Her vocalizations also seem normal, and the owner is reporting normal bowel movements/urination.

Which cranial nerve(s) are showing a deficit?

Answer 4

glossopharyngeal (9)

Question 5

what does the nucleus refer to

Answer 5

collection of cell bodies in the CNS

Question 6

T/F: spinal nerves are always sensory

Answer 6

FALSE - always mixed function

Question 7

Give the cranial nerve in the:

telencephalon

Answer 7

CN 1

Question 8

give the cranial nerve in the:

diencephalon

Answer 8

CN 2

Question 9

give the cranial nerve in the:

mesencephalon

Answer 9

CN 3 and 4

Question 10

give the cranial nerve in the:

metencephalon

Answer 10

CN 5

Question 11

give the cranial nerve in the:

myelencephalon

Answer 11

CN 6 - 12

Question 12

what travels through the optic canal

Answer 12

optic nerve (CN 2)

Question 13

what travels through the orbital fissure

Answer 13

oculomotor n. (CN 3)
trochlear n. (CN 4)
ophthalmic branch of CN 5
abducent (CN 6)

Question 14

what travels through the round foramen

Answer 14

maxillary n. branch of CN 5

Question 15

what travels through the tympano-occipital fissure

Answer 15

glossopharyngeal n. (CN 9)
vagus n. (CN 10)
Accessory n. (CN 11)

Question 16

regular motor

Answer 16

to striated muscle

Question 17

autonomic motor

Answer 17

parasympathetic to glands and smooth muscle

Question 18

general sensory

Answer 18

nerves to brain

Question 19

special sensory

Answer 19

nerves to the brain for smell, sight, taste, hearing, and balance

Question 20

what is the function of CN 1?

Answer 20

olfactory (smell) - special sensory

Question 21

what does CN 1 pass-through

Answer 21

cribriform plate

Question 22

if CN 1 is damaged what happens

Answer 22

anosmia (loss of sense of smell)

Question 23

what is the optic chiasm?

Answer 23

crossing of optic n. fibers

Question 24

what is the function of CN 2 (optic)?

Answer 24

sight - special sensory

Question 25

what is unique about the optic n.

Answer 25

extension of the brain rather than an actual nerve

Question 26

what does the menace response test

Answer 26

CN 2 and 7

Question 27

what does the pupillary light response test

Answer 27

CN 2 and 3

Question 28

if the CN 2 is damaged what happens

Answer 28

no menace/pupillary response

Question 29

what is innervated by CN 3 (oculomotor n.)

Answer 29

levator palpebrae superioris m. dorsal rectus m. medial rectus m. ventral rectus m. ventral oblique m. constrictor pupillae m.

Question 30

if the eye appears to be pulled laterally, what muscle is not correctly working

Answer 30

medial rectus m.

Question 31

ptosis is caused by what muscle

Answer 31

levator palpebrae

Question 32

anisocoria

Answer 32

dilated eye

Question 33

what part of the oculomotor nerve is parasympathetic

Answer 33

the branch going to the ciliary body and constrictor pupillae m.

Question 34

what is innervated by CN 4 (trochlear n.)

Answer 34

trochlea and dorsal oblique m.

Question 35

T/F: extorsion (CN 4 damage) is most noticeable in animals with non-round pupils

Answer 35

TRUE

Question 36

what are the three branches of CN 5 (trigeminal n.)

Answer 36

ophthalmic maxillary mandibular

Question 37

give what the ophthalmic nerve passes through and innervates

Answer 37

orbital fissure medial orbit/canthus, eyeball, nasal mucosa, frontal sinus

Question 38

if the ophthalmic n. is damaged what happens

Answer 38

no closure of the eye when the medial canthus is touched

Question 39

give what the maxillary nerve passes through and innervates

Answer 39

round foramen lateral orbit/canthus, nasal mucosa, hard/soft palates, skin of rostral face, upper lip and teeth

Question 40

if the maxillary n. is damaged what happens

Answer 40

no response when the lateral canthus or upper lip/whiskers are touched

Question 41

give what the mandibular nerve passes through and innervates

Answer 41

oval foramen muscles of mastication (temporalis, masseter, buccal, pterygoid), rostral 2/3rds of tongue, lower lip and teeth

Question 42

if there is a bilateral lesion to the mandibular n. what happens

Answer 42

dropped jaw

Question 43

if there is a unilateral lesion to the mandibular n. what happens

Answer 43

ipsilateral m. atrophy

Question 44

the upper teeth are innervated by

Answer 44

maxillary n. and infraorbital n.

Question 45

the lower teeth are innervated by

Answer 45

the inferior aveolar and mental n. branches of the mandibular n.

Question 46

what does CN 6 (abducens) innervate

Answer 46

lateral rectus m. retractor bulbi m.

Question 47

if the CN 6 (abducens) nerve is damaged what happens

Answer 47

medial strabisimus

Question 48

what does CN 7 (facial) nerve pass-through

Answer 48

the middle and inner ear

Question 49

what does CN 7 (facial) nerve innervate

Answer 49

ear pinna (sensory) facial muscles (motor) lacrimal, nasal, and palatine glands taste buds (rostral 2/3rds; special sensory)

Question 50

damage of the facial n. results in

Answer 50

loss of menace response facial paralysis

Question 51

T/F: CN8 (vestibulocochlear n.) never leaves the skull

Answer 51

TRUE

Question 52

what are common vestibular disease signs

Answer 52

1. head tilt 2. nystagmus 3. ataxia

Question 53

what is temporohyoid osteoarthropathy

Answer 53

disease of the articulation between temporal bone and hyoid apparatus in horses pressure of swallowing can cause fractures to the temporal bone affects CN 7 and 8

Question 54

what does CN 9 (glossopharyngeal) nerve innervate

Answer 54

salivary glands muscles of pharynx taste (1/3rd caudal) sensory to caudal tongue

Question 55

what 3 nerves pass through the tympano-occipital fissure

Answer 55

CN 9, 10, and 11

Question 56

what does CN 10 (vagus n.) innervate

Answer 56

taste buds on epiglottis mm. of larynx, pharynx, esophagus viscera

Question 57

what nerves can be tested via the gag reflex

Answer 57

CN 9 and 10

Question 58

What muscles does the CN 11 (accessory nerve) innervate

Answer 58

trapezius cleidocephalicus sternocephalicus omotransversarius

Question 59

what is cribbing

Answer 59

hypertrophy of sternocephalicus in horses

Question 60

what does CN 12 (hypoglossal n.) innervate

Answer 60

muscles of the tongue

Question 61

what is guttural pouch disease and what nerves may we be worried about

Answer 61

bacterial/fungal infection of the auditory tube expansion CN 9, 10, 11, and 12