Part 5: Cranial nerves Flashcards
CN (cranial nerve general) + functions of the _______
12 prs of peripheral nerves (like spinal nerves)
* Numbered (Roman numerals) from I to XII
* Essentially run the functions of the head & neck
(except CN X)
CN pure ___/_____ or _____
- Some CNs pure motor, some pure sensory,others
mixed
CN arise and interact with _____ (which types? where?)
Arise from & interact with nuclei (motor, sensory,
parasympathetic) in brainstem
Cell bodies of sensory neurons live in
_____CN ganglia
(like dorsal root ganglia)
Label nerves
I – Olfactory
II – Optic
III – Oculomotor
IV – Trochlear
V – Trigeminal
VI – Abducens
VII – Facial
VIII –Vestibulocochlear
(Audiovestibular)
IX – Glossopharyngeal
X – Vagus
XI – Spinal Accessory
XII - Hypoglossal
CN I sits on ___ and extends in ___
cribiform plate
olfactory epithelium
CN I – Olfactory Nerve is ____ and responsible for ____.
Pure sensory – responsible for smell (olfaction)
Olfactory Nerve pathway
Terminate in olfactory bulb -> olfactory tract
* Olfactory tract -> 1o olfactory cortex (temporal lobe)
Olfactory nerve is the only sensory system to _____. Disease of nerve: _____
bypass thalamus (sensory relay station)
* Damage or Disease -> hyposmia and/or anosmia
CN II – Optic Nerve is _____ and responsible for ____
Pure sensory – vision
CN II nerve pathway
Axons of ganglion cells -> Optic Nerve (~ 1 million
axons)
* Optic n ->Optic Chiasm > Optic tract > lateral
geniculate nucleus (thalamus) > Optic Radiations >
1o Visual Cortex
* 1o Visual Cortex(posterior ) – medial aspect of occipital lobe on either side of Calcarine Sulcus
Visual fields are projected onto visual cortex _____
Damage or disease of CN II - >
in an inverted and reversed fashion
visual field defects (cortical blindness)
Calcarine Sulcus (def.)
caudal end of the medial surface of the brain
CN III, IV, VI share _____
similar function in controling muscles of eye
rectus muscle
straight
CN III – Oculomotor Nerve is a _______ and arises from ______
somatic motor and Parasympathetic (PS) – mixed nerve
midbrain
motor component of CIII supplies _____
medial rectus, superior rectus, inferior rectus, inferior oblique, levator palpebrae superioris (elevator of upper eyelid)
Hint to remember: eye muscle innervation
CIII controls all extra-ocular muscles except LR6SO4
- (LR6SO4 lateral rectus – CN VI, superior oblique – CN IV)
Parasympathetic action of CIII controls for________ .Damage or disease of CIII -> _____
pupillary constriction & accommodation (ciliary ganglion)
pupillary dilation (unopposed sympathetics) and ophthalmoplegia (eye movements weakened or paralysed)
CN IV - Trochlear Nerve comes off ___
posterior area of brainstem (wraps around)
CN IV – Trochlear Nerve is the ___. It is a ____ nerve. it supplies _______.
Smallest cranial nerve
Pure motor
supplies one muscle - superior oblique
isolated damage to CN IV is ______
uncommon
CN VI - Abducent Nerve is a _____. It supplies ______. It is located at ______. It is ______ of cranial nerves
-Pure motor nerve
-supplies one muscle – lateral rectus (abducts the eye, hence the name ‘abducent’)
-pontomedullary junction
longest intracranial course
CN VI is vulnerable to ______. Damage ->_______ –> ______ –> _____ —> _____
Patient complains of ______
-injury in head trauma or raised intracranial
pressure (intracranial hemorrhage, brain tumors)
-paralysis of lateral rectus
-unopposed action of medial rectus
-eye deviates medially
-squint (strabismus)
-double vision (diplopia)
Label muscles and nerves
black: levator palpebrae superioris m
purple: oculomotor nerve (CN 3)
orange: superior rectus
blue: ciliary ganglion
grey: medial rectus
pink: inferior rectus
green: inferior oblique
label nerves + muscles
green: superior oblique
purple: trochlear nerve (CN 4)
label muscles + nerves
blue: abducent nerve (CN 6)
orange: lacteral rectus
CN V - Trigeminal Nerve is _______ (from ___) and has ______ arising from ____. Disease: _____
Mixed nerve – sensory and motor (from pons)
Has 3 divisions (branches) arising from trigeminal
ganglion
- Disease – Trigeminal Neuralgia (Tic Douloureux)
- Mainly V2 and V3 (pain nerves one side)
branches of CN V - trigeminal nerve
- V1 – Ophthalmic nerve -> eye (pure sensory)
- V2 – Maxillary nerve - > cheek (pure sensory)
- V3 – Mandibular nerve -> mandible (motor + sensory)
CN V1 - ______Branch is ____ and supplies sensation to ____ and general sensory innervation to _____. It supplies sensation to ____ via _______
- Ophthalmic
-pure sensory
the frontal and ethmoidal paranasal air sinuses,
nasal cavity
-the upper eyelid, side of the nose, forehead and scalp via supraorbital nerves
label
blue: supraorbital nerves
green: ophthalmic nerve
purple: trigeminal ganglion
orange: ciliary ganglion
label
blue: infraorbital nerves
orange: maxillary nerve
purple: trigeminal ganglion
red: pterygopalatine ganglion
CN V2 – Maxillary Nerve is ____and enters _____ through ____. It supplies sensation to ______ and to ____ via _____
-Pure sensory
-floor of orbit
-inferior orbital fissure
- maxillary air sinus
- nasal cavity
- maxillary (upper) teeth and gums
- lower eyelid, skin of cheek, upper lip ( via infraorbital nerve)
CN V3 - Mandibular Branch is ______ and ____ branch of CNV
-Mixed nerve – somatic sensory and somatic motor -largest branch
CN V3 Motor supplies ______. Sensory part supplies _____ and _____ via _____ and general sensation to _____ via _____. CNV3 ends as ____ in ____. It carries proprioceptive information from _____ to control _____
muscles of mastication +smiling
-lower lip, skin of mandible
- mandibular teeth and gums via inferior alveolar nerve)
- anterior 2/3 of tongue via lingual nerve
-Ends as mental nerve in chin
-muscles of mastication to brainstem
-force of bite
Inferior Alveolar Nerve where?
the the CN V3 branch enters bone (where dentist numb)
label
green: lingual nerve
red: mandibular nerve
orange: trigeminal ganglion
blue: otic ganglion
yellow: inferior alveolar nerve
purple: submandibular ganglion
pink: mental nerve
CN VII – Facial Nerve is a ______. It is attached to ______. Its sensory nerve cell bodies are in ____ Damage:
Mixed nerve – Somatic motor, somatic sensory &
parasympathetic
* Attached to pons
geniculate ganglion
* Damage or disease :Patient may lose taste (partly), salivation (partly) or lacrimation in one eye or Bell’s Palsy (hemi-facial paralysis)
CN VII – Facial Nerve motor function _______. sensory function: _____.
-muscles of facial expression (5 sets of branches)
-taste to anterior 2/3 of tongue (via chorda
tympani – joins lingual n)
parasympathetic function of CN VII: ______
- lacrimal gland for tearing (lacrimation) via
pterygopalatine ganglion (V2) - Submandibular & sublingual salivary glands via
submandibular ganglion (V3)
label
black: pterygopalatine ganglion
purple: temporal branch
orange: zymogamtic branch
red: buccal branch
green: mandibular branch
yellow:cervical branch
blue: submandibular ganglion
dark green: stylomastoid foramen
pink: chonrda tympani nerve to tongue
grey: geniculate ganglion
brown: facial nerve (CN VII)
Chorda Tympani Nerve
of CN VII to tongue
CN VIII – Vestibulocochlear Nerve is ____ with _____
Damage or disease -> _______
-Pure sensory nerve with 2 components (Vestibular + Cochlear)
-difficulty in localizing sound (deafness rare)
2 components of vestibulocochlear nerve: Vestibular supplies ____ —> affects _____. Disease: _____
- supplies vestibular apparatus (semicircular canals +
vestibule)–> affect balance and equilibrium - Disease: Meniere’s syndrome (vertigo, nausea, vomiting)
2 components of vestibulocochlear nerve: Cochlear supplies ____ —> affects _____. A pathway in where carries this info to _______Disease: _____
- supplies organ of Corti in cochlea
-hearing - Bilateral central pathway in brainstem carries this
information to the temporal lobe -> 1o auditory cortex - Damage or disease -> difficulty in localizing sound
(deafness rare)
label
green: vestibular branch
blue: vestibular apparatus
purple: organ of corti
pink: cochlear branch
yellow: vestibulocochlear nerve
CN IX - Glossopharyngeal Nerve is a ______ that supplies ____ attached to ______ and regulates _____. Damage or disease: _____
- Mixed nerve – somatic motor, somatic sensory and
parasympathetic - Supplies the tongue and the pharynx
- Attached to medulla
- Regulates the gag reflex (important)
*difficulty in swallowing, loss of gag reflex
CN IX – Motor function? sensory general? sensory special? parasympathetic?
-Motor to one muscle: stylopharyngeus (elevates pharynx)
-Sensory (general):posterior 1/3 tongue, pharynx, carotid sinus + body (for carotid sinus reflex)
-Sensory (special) : taste to posterior 1/3 of tongue
-Parasympathetic : supplies parotid gland via otic ganglion
label
black: otic ganglion
yellow: lingual branch
red: cartoid sinus
green: pharyngeal branches
blue: parotid gland
pink: CN IX ( glossopharyngeal nerve
CN X – Vagus Nerve is _____ attached to ____. Damage: ______
Mixed nerve – motor, sensory and parasympathetic
* Attached to medulla
*difficulty in speech and swallowing
CN X – Somatic Motor Functions
- Motor to muscles of the palate, pharynx and larynx
+ voice box
CN X – Sensory Functions
Sensory to muscles of the palate, pharynx and larynx
*(stretch) Baroreceptor to hollow organs (ex. stomach + bowel)
* Carries visceral afferents from the organs to
the CNS
CN X – Parasympathetic Activity
- Essentially functions as the parasympathetic nerve
for viscera - Parasympathetic motor to smooth muscle in
thoracic and abdominal organs up to distal part of
transverse colon - Regulates heart rate (slows it down)
CN XI – Spinal Accessory Nerve has ______. attached to _____. supplies _____. damage: ______
Somatic Motor function only
* Attached to medulla and upper spinal cord
- supplies trapezius and
sternocleidomastoid muscles in the neck
*weakness when shrugging (elevating) shoulders, turning head to one side against resistance
CN XII - Hypoglossal Nerve is ____. attached to ____ supplies ____. damage: ____
Pure motor nerve
* Attached to medulla
* Supplies the muscles of the tongue
* Damage or disease – inability to protrude tongue
symmetrically
label
orange: accessory root
yellow: vagus nerve (CN X)
red: spinal accesory nerve (CN XI)
green: accesory branch
blue: spinal branch
pink: strenocleidomastoid
purple: spinal root
black: trapezius
label
black: hypoglossal nerve
