Cranial Nerves Flashcards

1
Q

General CN Info

A

All are part of the PNS and arise directly from the brain (brainstem) except CNs I and II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

CN I: Olfactory Nerve

A

Afferent Only
Function: Special sense of olfaction/smell
Clinical Significance: Loss of smell due to erosion from adenocarcinomas (nasla tumor)
Processes from receptor cells on roof of nasal epithelium assemble into bundles that extend to olfactory bulb
Foramen: Cribiform Plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

CN II: Optic Nerve

A

Afferent Only
Function: Convey visual information
Extension of fiber tracts of diencephalon (part of CNS)
Receptors are rods and cones
Foramen: Optic Canal
Clinical Significance: Neuro exam (Menace, PLRs, Visual tracking). Hypovitaminosis A changes structure of optic canal in cows, leads to blindness)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

CN III: Oculomotor Nerve

A

Efferent Only
Function:
Innervates extraocular muscles: Dorsal, ventral, and medial rectus + ventral oblique.
Innervates upper eyelid: Levator palpebrae
Parasympathetic Innervation of constrictor pupillary mm and ciliary muscle for pupil contraction
Clinical Significance: Strabismus (ventrolateral: Down and out)
Foramen: Orbital Fissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

CN IV: Trochlear Nerve

A

Efferent Only
Function: Innervates contralateral dorsal oblique mm. (extraocular muscles)
Only CN on dorsal aspect of brainstem and only CN to innervate contralateral side
Foramen: Orbital Fissure
Clinical Significance: Only seen in slit pupil species-> Dorsomedial strabismus (V shaped pupils)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

CN V: Trigeminal Nerve

A

Mixed
3 Branches: Ophthalmic, Maxillary, Mandibular
Afferent: Sensory to the face (uses all three branches)
Efferent: Innervates muscles of mastication (mandibular branch)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

CN VI: Abducens Nerve

A

Efferent Only
Function: Innervates lateral rectus muscle and retractor bulbi
Foramen: Orbital Fissure
Clinical Significance: Medial Strabismus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

CN VII: Facial Nerve

A

Mixed Only
Function (4):
Afferent Sensory-> Small area of ear
Afferent Special-> Taste: rostral 2/3 of tongue + hard & soft palate.
Efferent-> Muscles of Facial Expression. All 5 groups: Nostrils, Lips, Cheek, Eyelid (w/ CNIII), and external ears
Parasympathetic Innervation-> Glands of the head. Controls salivation (IX and X contribute afferently as well) through mandibular and lingual salivary glands (fibers traveling through chorda tympani nerve which senses taste from rostral 2/3s of tongue)
Foramen: Stylomastoid
Clinical significance: Droopy face

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

CN VIII: Vestibulocochlear Nerve

A

Afferent Only
Function: Vestibular-> Balance and Cochlear-> Hearing
Foramen: Internal Acoustic Meatus (Does not exit skull)
Clinical Significance: Leaning towards one side and head tilt for vestibular portion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

CN IX: Glosspharyngeal Nerve

A

Mixed
Function:
Afferent-> Sensory information from upper pharynx and caudal 1/3 of the tongue
Important for gagging and swallowing reflex
Taste to caudal 1/3 of tongue
Carries visceral sensory information from chemoreceptors and baroreceptors in the carotid body and sinus. i.e. BP, PaCO2, blood pH
Efferent-> Innervates muscles of pharynx
Parasympathetic innervation-> Salivary gland
Foramen-> Jugular Foramen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

CN X: Vagus Nerve

A

Mixed
Function:
Afferent: Carries visceral information from larynx, esophagus, trachea, abdominal, thoracic viscera, stretch receptors of aortic arch and chemoreceptors of the aortic bodies
General sensory from pharynx, back of ear and external meatus
Minor taste sensation from epiglottic region
Efferent-> Motor to muscles of pharynx and most of larynx
Parasympathetic Innervation-> smooth muscles. Also glands of pharynx + larynx and viscera of thorax/abdomen.
Foramen: Jugular Foramen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

CN XI Accessory Nerve

A

Efferent Only
Spinal and Cranial part.
Efferent-> Motor to muscle of larynx and esophagus, neck and shoulders (trapezius, cleidocervicalis, sternocephalicus and cleidomastoideus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

CN XII: Hypoglossal Nerve

A

Efferent Only
Function: Motor to intrinsic tongue muscles and some extrinsic including hyoglossus, genioglossus, styloglossus
Foramen: Hypoglossal Foramen
Clinical Significance: Paresis/paralysis-> atrophy of tongue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

CN V: Ophthalmic Branch

A

Afferent
Function: Sensory (skin) of upper face, dorsal nasal cavity (nasocortical reflex along w/ maxillary), and large part of the eye and its associated structures (corneal reflex, also palpebral reflex along w. maxillary.)
Afferent Skin/Eye-> Frontal, lacrimal, and infratrochlear nerves. Long ciliary nerves for cornea.
Afferent Nasal Cavity-> Ethmoidal nerve
Foramen: Orbital Fissure
Clinical Significance: No protection of cornea with deficit-> Corneal ulcer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

CN V: Maxillary Branch

A

Afferent
Function: Sensory (skin) of upper eyelid, nasal mucosa, upper teeth, upper lip, and nose and lower eyelid
Foramen: Round/Rostral Alar
Clinical Significance: Lack of closing jaw

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

CN V: Mandibular Branch

A

Afferent-> Sensory to rostral 2/3 of tongue, oral cavity, lower face and teeth
Efferent-> Motor to muscles of mastication. Also innervates tensor tympani, tensor veli palatini (minor)