Cranial Nerve lecture Flashcards
CN I
Olfactory n
->Sense of smell
Olfactory neurons originate where
Olfactory epithelium of the caudal nasal mucosa
Where do olfactory neuronal axons pass?
Through cribiform plate to reach olfactory bulb of the brain
Relevance of CN I
Anosmia (loss of sense of smell)
Detector dogs
Search and rescue dogs
CN II
Optic n
->Vision, pupil size, visual reflexes/responses
Where do optic n originate?
Retina (ganglion cells)
Optic n neuronal axons leave where to form what
Leave eye at optic disc to form optic n
Where is visual info relayed?
Occipital cortex
Pupillary Light Reflex uses what n?
CN II- Optic
->Sensory
CN III-Oculomotor
->Motor
Menace Response uses what n?
CN II- Optic
->Sensory
CN VII- Facial (blink-orbicularis oculi)
_>Motor
What n is involved with vision, PLR and menace response?
Optic n
CN II
What n are in charge of eye movement. What muscles do all of the control?
CN III-Oculomotor
CN IV- Trochlear
CN VI- Abducent
Extraocular muscles (skeletal muscle)
Oculomotor n (CN III) muscles
DMV rectus
Ventral oblique
Levator palebrae superioris
Trochlear n (CN IV) muscles
Dorsal oblique
Abducent n (CN VI) muscles
L rectus
Rectractor bulb
Strabismus
Altered eye position
CN III dysfunction may result in
Dilated pupil
parasympathetic component
Ventrolateral strabismus w/dilated pupil can be caused by
CN III
Extorsion can be caused by
CN IV
Medial strabismus can be caused by
CN VI
What are some oculomotor (CN III) fxns?
Extraocular muscle control
Constrictor muscle of pupil (sphincter pupillae)
Where does CN III originate
Brainstem and supplies motor innervation to extraocular muscles and constrictor muscle of pupil
For pupil symmetry/size describe CN II and III
II=sensory
III=constriction, parasymp
For pupil symmetry/size explain sympathetic involvement
Dilation with excitement
Originates from T1-T2 (pregang) and travels in vagosymp trunk (cervical symp compoent) to cranial cervical ganglion (postgang)
CN V
- Sensory
- Motor
Trigeminal n
Sensory-face, eye, mouth
Motor-muscles of mastication
3 branches of trigeminal n (CN V)
Ophthalmic (sensory)
Maxillary (sensory)
Mandibular (sensory and motor)
CN VII
Facial n
Fxns of CN VII (facial n)
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
CN VIII
Vestibulocochlear
->Hearing and balance
Components of CN VIII
Vestibular component (relays sensory info for BALANCE)
Auditory component (hearing)
Test to measure effectiveness of CN VIII
Brainstem Auditory Evoked Response Test (BAER)
CN IX
Glossopharyngeal n
Fxns of CN IX (Glossopharyngeal n)
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)
CN X
Vagus n
CN X fxns
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)
Explain CN X (Vagus n) innervation to larynx
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
Explain what n would be involved with laryngeal paralysis
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.
CN XI
Accessory n
Motor to trapezius and other neck muscles
CN XII
Hypoglossal
Motor to tongue muscles (intrinsic and extrinsic)
What n comes out of the orbital fissure?
CN 3,4,5(ophthalmic n),6
What n comes out of the optic canal?
CN 2
What n comes out of the rostral alar foramen?
CN 5 (maxiallary n)
What n comes out of oval foramen?
CN 5 (mandibular)
What n comes out of the hypoglossal canal?
CN 12
What n comes out of the tympano-occipital fissure?
CN 9, 10, 11
What are branches of mandibular branch of CN 5
Inferior alveolar n
Lingual n
What branch of facial n travels with lingual n of CN 5 (mandibular branch)
Chorda tympani
What are branches of CN 7
Palpebral n
Rostral auricular n
Auriculopalpebral n
