Week 6 Flashcards
where are the receptors for the olfactory nerve
caudal aspect of nasal cavity in respiratory epithelium
where are the axons for olfactory nerve
in cribiform plate; travel as lateral olfactory tract to paleopallium to piriform lobe; some travel in medial olfactory tract to hypothalamus for unconscious smell perception
usually damage to olfactory nerve occurs where?
peripherally
where are receptors for optic nerve
retina to optic disc
where are the axons for optic nerve
optic nerve, through optic canal, to optic chiasm; to optic tracts,
to LGN and occipital lobe for conscious vision
to PTN for unconsious vision
what do you see when optic nerve is damaged
visual deficits or blindness
PLR if lesion cranial to chiasm
no plr
plr if lesion caudal to chiasm
plr present
where does most causes of blindness occur
in the eye
how else can you assess optic nerve
menace response
when you have compression of the oculomotor nerve, what innervation goes first?
parasympathetic innervation, then somatic innervation
somatic signs of damage of oculomotor
ventrolateral strabismus in SA and lateral strabismus in LA
Ptosis
what are the signs of damage of GVE oculomotor nerve
mydriasis
what do you see if the trochlear nerve is damaged
rotary strabismus (hard to assess in dogs); not clinically relevent
what do you see if the abducens nerve is damaged
medial deviation of globe
how do you assess II, IV, VI
look at position and movement of eye; oculocephalic reflex
where does the split for the trigeminal come occur
inside the brain case
where does the ophthalamic nerve exit
the orbital fissure (dog and horse)
foramen orbitorotundum in ox
where does the maxillary nerve
rostral alar foramen via round foramen (dogs and horse) foramen orbitorotundum (ox)
what is sensory to the external ear canal
CN VII
What is sensory to the caudal pinna
C2 spinal (greater auricular nerve)
trigeminal is motor to
muscles of mastication
know az in small animals and horse and ruminants
notes pg. 109-110
what occurs when you damage the trigeminal nerve
anesthesia and deficitis with palpebral, corneal, and trigeminofacial reflexes; LMN signs of muscles of mastication (via mandibular nerve); protrusion of the third eyelid due to atrophy of pterygoid muscles;
how can you assess trigeminal nerve (besides relfexes)
open mouth to assess jaw strength in unilateral flaccid paralaysis (if bilateral- drop jaw)
facial nerve is motor to
muscles of facial expression and lacrimal gland (gve parasympathetic)
facial nerve exits via
stylomastoid foramen
what are the 3 main branches of the facial nerve
buccal branches (dorsal and ventral; only 1 branch in horse) auriculopalpebral n. (innervates orbicularis oculi m. via palpebral nerve)
what do you see when the facial nerve is damaged
facial paralysis; check for normal tearing! (a lot of times tearing will be ok; already split from facial at stylomastoid foramen and hitches a ride with ophthalamic)
damage of facial in dog and cat
nasal deviation occasionally seen in dog
facial damage in horse
nasal deviation to opposite side of damage; ptosis (angularis oculi m.) (can view by angle of lashes)
facial nerve damage in cattle
ptosis (angularis oculi m.)
otitis media interna
can damage CN VII and VII;
medulla compressive tumors
VN VII brings info to medulla close to VII so can see with central and periptheral lesions (vestibular dz and loss of senstion of inner ear and other facial nerve signs)
vestibular component of vestibulocochlear receptors are in
inner ear in semicircular canals; utricle and macula
damage to cochlear component
deafness almost always a peripheral problem (some drugs are ototoxicl- aminoglycosides; congenital deafness- linked to white hearcoat)
vestibular component damage
vestibular disease; head tilt; vestibular dz is a unilateral dz and can be unilateral centrally or unilateral peripherally
glossopharyngeal nerve is motor to
pharyngeal muscles (involuntary phase of swallowing)
glossopharyngeal nerve sensory to
pharyngeal mucosa
vagus nerve sensory to
pharyngeal mucosa and larynx, trachea
vagus nerve motor to
pharynx, larynx, esophagus
what do you see if you damage CNN IX, X
dysphagia (9 and 10) dysphonia (x) inspiratory dyspnea (x) megaesophagus (x) cardiovascular changes
hypoglossal nerve motor to
tongue
damage of hypoglossal nerve
atrophy (typically lateral)
dyspagia (bilateral)
