Lecture 44 - Cranial Nerves 1 & 2 Flashcards
T/F: cranial nerves are classified as part of the peripheral nervous system
TRUE
which cranial nerves carry parasympathetic motor fibers?
CN 3, 7, 9, and 10
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?
CN 3 and 5
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?
glossopharyngeal (9)
what does the nucleus refer to
collection of cell bodies in the CNS
T/F: spinal nerves are always sensory
FALSE - always mixed function
Give the cranial nerve in the:
telencephalon
CN 1
give the cranial nerve in the:
diencephalon
CN 2
give the cranial nerve in the:
mesencephalon
CN 3 and 4
give the cranial nerve in the:
metencephalon
CN 5
give the cranial nerve in the:
myelencephalon
CN 6 - 12
what travels through the optic canal
optic nerve (CN 2)
what travels through the orbital fissure
oculomotor n. (CN 3)
trochlear n. (CN 4)
ophthalmic branch of CN 5
abducent (CN 6)
what travels through the round foramen
maxillary n. branch of CN 5
what travels through the tympano-occipital fissure
glossopharyngeal n. (CN 9)
vagus n. (CN 10)
Accessory n. (CN 11)
regular motor
to striated muscle
autonomic motor
parasympathetic to glands and smooth muscle
general sensory
nerves to brain
special sensory
nerves to the brain for smell, sight, taste, hearing, and balance
what is the function of CN 1?
olfactory (smell) - special sensory
what does CN 1 pass-through
cribriform plate
if CN 1 is damaged what happens
anosmia (loss of sense of smell)
what is the optic chiasm?
crossing of optic n. fibers
what is the function of CN 2 (optic)?
sight - special sensory
what is unique about the optic n.
extension of the brain rather than an actual nerve
what does the menace response test
CN 2 and 7
what does the pupillary light response test
CN 2 and 3
if the CN 2 is damaged what happens
no menace/pupillary response
what is innervated by CN 3 (oculomotor n.)
levator palpebrae superioris m.
dorsal rectus m.
medial rectus m.
ventral rectus m.
ventral oblique m.
constrictor pupillae m.
if the eye appears to be pulled laterally, what muscle is not correctly working
medial rectus m.
ptosis is caused by what muscle
levator palpebrae
anisocoria
dilated eye
what part of the oculomotor nerve is parasympathetic
the branch going to the ciliary body and constrictor pupillae m.
what is innervated by CN 4 (trochlear n.)
trochlea and dorsal oblique m.
T/F: extorsion (CN 4 damage) is most noticeable in animals with non-round pupils
TRUE
what are the three branches of CN 5 (trigeminal n.)
ophthalmic
maxillary
mandibular
give what the ophthalmic nerve passes through and innervates
orbital fissure
medial orbit/canthus, eyeball, nasal mucosa, frontal sinus
if the ophthalmic n. is damaged what happens
no closure of the eye when the medial canthus is touched
give what the maxillary nerve passes through and innervates
round foramen
lateral orbit/canthus, nasal mucosa, hard/soft palates, skin of rostral face, upper lip and teeth
if the maxillary n. is damaged what happens
no response when the lateral canthus or upper lip/whiskers are touched
give what the mandibular nerve passes through and innervates
oval foramen
muscles of mastication (temporalis, masseter, buccal, pterygoid), rostral 2/3rds of tongue, lower lip and teeth
if there is a bilateral lesion to the mandibular n. what happens
dropped jaw
if there is a unilateral lesion to the mandibular n. what happens
ipsilateral m. atrophy
the upper teeth are innervated by
maxillary n. and infraorbital n.
the lower teeth are innervated by
the inferior aveolar and mental n. branches of the mandibular n.
what does CN 6 (abducens) innervate
lateral rectus m.
retractor bulbi m.
if the CN 6 (abducens) nerve is damaged what happens
medial strabisimus
what does CN 7 (facial) nerve pass-through
the middle and inner ear
what does CN 7 (facial) nerve innervate
ear pinna (sensory)
facial muscles (motor)
lacrimal, nasal, and palatine glands
taste buds (rostral 2/3rds; special sensory)
damage of the facial n. results in
loss of menace response
facial paralysis
T/F: CN8 (vestibulocochlear n.) never leaves the skull
TRUE
what are common vestibular disease signs
- head tilt
- nystagmus
- ataxia
what is temporohyoid osteoarthropathy
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
what does CN 9 (glossopharyngeal) nerve innervate
salivary glands
muscles of pharynx
taste (1/3rd caudal)
sensory to caudal tongue
what 3 nerves pass through the tympano-occipital fissure
CN 9, 10, and 11
what does CN 10 (vagus n.) innervate
taste buds on epiglottis
mm. of larynx, pharynx, esophagus
viscera
what nerves can be tested via the gag reflex
CN 9 and 10
What muscles does the CN 11 (accessory nerve) innervate
trapezius
cleidocephalicus
sternocephalicus
omotransversarius
what is cribbing
hypertrophy of sternocephalicus in horses
what does CN 12 (hypoglossal n.) innervate
muscles of the tongue
what is guttural pouch disease and what nerves may we be worried about
bacterial/fungal infection of the auditory tube expansion
CN 9, 10, 11, and 12
