Cranial Nerve lecture

Question 1

CN I

Answer 1

Olfactory n

->Sense of smell

Question 2

Olfactory neurons originate where

Answer 2

Olfactory epithelium of the caudal nasal mucosa

Question 3

Where do olfactory neuronal axons pass?

Answer 3

Through cribiform plate to reach olfactory bulb of the brain

Question 4

Relevance of CN I

Answer 4

Anosmia (loss of sense of smell)

Detector dogs

Search and rescue dogs

Question 5

CN II

Answer 5

Optic n

->Vision, pupil size, visual reflexes/responses

Question 6

Where do optic n originate?

Answer 6

Retina (ganglion cells)

Question 7

Optic n neuronal axons leave where to form what

Answer 7

Leave eye at optic disc to form optic n

Question 8

Where is visual info relayed?

Answer 8

Occipital cortex

Question 9

Pupillary Light Reflex uses what n?

Answer 9

CN II- Optic
->Sensory

CN III-Oculomotor
->Motor

Question 10

Menace Response uses what n?

Answer 10

CN II- Optic
->Sensory

CN VII- Facial (blink-orbicularis oculi)
_>Motor

Question 11

What n is involved with vision, PLR and menace response?

Answer 11

Optic n

CN II

Question 12

What n are in charge of eye movement. What muscles do all of the control?

Answer 12

CN III-Oculomotor

CN IV- Trochlear

CN VI- Abducent

Extraocular muscles (skeletal muscle)

Question 13

Oculomotor n (CN III) muscles

Answer 13

DMV rectus
Ventral oblique
Levator palebrae superioris

Question 14

Trochlear n (CN IV) muscles

Answer 14

Dorsal oblique

Question 15

Abducent n (CN VI) muscles

Answer 15

L rectus

Rectractor bulb

Question 16

Strabismus

Answer 16

Altered eye position

Question 17

CN III dysfunction may result in

Answer 17

Dilated pupil

parasympathetic component

Question 18

Ventrolateral strabismus w/dilated pupil can be caused by

Answer 18

CN III

Question 19

Extorsion can be caused by

Answer 19

CN IV

Question 20

Medial strabismus can be caused by

Answer 20

CN VI

Question 21

What are some oculomotor (CN III) fxns?

Answer 21

Extraocular muscle control

Constrictor muscle of pupil (sphincter pupillae)

Question 22

Where does CN III originate

Answer 22

Brainstem and supplies motor innervation to extraocular muscles and constrictor muscle of pupil

Question 23

For pupil symmetry/size describe CN II and III

Answer 23

II=sensory

III=constriction, parasymp

Question 24

For pupil symmetry/size explain sympathetic involvement

Answer 24

Dilation with excitement

Originates from T1-T2 (pregang) and travels in vagosymp trunk (cervical symp compoent) to cranial cervical ganglion (postgang)

Question 25

CN V - Sensory - Motor

Answer 25

Trigeminal n Sensory-face, eye, mouth Motor-muscles of mastication

Question 26

3 branches of trigeminal n (CN V)

Answer 26

Ophthalmic (sensory) Maxillary (sensory) Mandibular (sensory and motor)

Question 27

CN VII

Answer 27

Facial n

Question 28

Fxns of CN VII (facial n)

Answer 28

Muscles of facial expression (menace response-blink) Sensory to inner pinna of ear Taste rostral 2/3s of tongue (chorda tympani branch travels with lingual n of V) Parasymp to lacrimal gland. salivary glands

Question 29

CN VIII

Answer 29

Vestibulocochlear | ->Hearing and balance

Question 30

Components of CN VIII

Answer 30

Vestibular component (relays sensory info for BALANCE) Auditory component (hearing)

Question 31

Test to measure effectiveness of CN VIII

Answer 31

Brainstem Auditory Evoked Response Test (BAER)

Question 32

CN IX

Answer 32

Glossopharyngeal n

Question 33

Fxns of CN IX (Glossopharyngeal n)

Answer 33

Gag response (sensory and motor to pharynx) Sensory caudal 1/3 tongue (including taste) Carotid sinus (baroreceptors), carotid body (chemoreceptor) Parasympathetic to salivary gland (ANS, parotid, zygomatic)

Question 34

CN X

Answer 34

Vagus n

Question 35

CN X fxns

Answer 35

Gag response (Sensory and motor to pharynx) Sensory to viscera supplied by the vagus (distal ganglion of the vagus) Parasympathetic to viscera (ANS) Carries recurrent laryngeal n (motor to larynx via caudal laryngeal n (motor to larynx via caudal laryngeal n) Cranial laryngeal (cricothyroid muscle, laryngeal mucosa)

Question 36

Explain CN X (Vagus n) innervation to larynx

Answer 36

Recurrent laryngeal n becomes caudal laryngeal n and supplies all of muscles of larynx EXCEPT CRICOTHYROID Cranial laryngeal n innervates cricothyroid muscle and laryngeal mucosa

Question 37

Explain what n would be involved with laryngeal paralysis

Answer 37

CN X Arytenoids would not be able to open easy to allow food to pass. To fix, tie back one side of arytenoid BUT it will always remain open and can lead to aspirating pneumonia.

Question 38

CN XI

Answer 38

Accessory n Motor to trapezius and other neck muscles

Question 39

CN XII

Answer 39

Hypoglossal Motor to tongue muscles (intrinsic and extrinsic)

Question 40

What n comes out of the orbital fissure?

Answer 40

CN 3,4,5(ophthalmic n),6

Question 41

What n comes out of the optic canal?

Answer 41

CN 2

Question 42

What n comes out of the rostral alar foramen?

Answer 42

CN 5 (maxiallary n)

Question 43

What n comes out of oval foramen?

Answer 43

CN 5 (mandibular)

Question 44

What n comes out of the hypoglossal canal?

Answer 44

CN 12

Question 45

What n comes out of the tympano-occipital fissure?

Answer 45

CN 9, 10, 11

Question 46

What are branches of mandibular branch of CN 5

Answer 46

Inferior alveolar n Lingual n

Question 47

What branch of facial n travels with lingual n of CN 5 (mandibular branch)

Answer 47

Chorda tympani

Question 48

What are branches of CN 7

Answer 48

Palpebral n Rostral auricular n Auriculopalpebral n