Cranial Nerve Overview Flashcards

1
Q

Pairs of cranial nn. And spinal nn. In PNS

A

12 cranial

31 spinal

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2
Q

Somatic component of peripheral nn. System

A

. Somatic sensory

. Somatic motor

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3
Q

Autonomic component of peripheral nervous system

A

. Visceral sensory

. Visceral nervous

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4
Q

T/F some cranial nn. Are mixed, and some only do sensory or motor

A

T

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5
Q

Nuclei

A

. Clusters of neuronal cell bodies located w/in CNS

. Cell bodies of motor and sensory neurons of CNS located in nuclei w/in gray matter in brainstem

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6
Q

Ganglia

A

. Clusters of neuronal cells odies outside of CNS

. Cell bodies of sensory neurons of CNS located in sensory ganglia in select locations throughout the head

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7
Q

Special sensory neurons

A

. Assoc. w/ special senses: visions, smell, taste, hearing, balance, equilibrium

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8
Q

Special motor neurons

A

. Assoc. w/ skeletal mm. That form w/in pharyngeal arch apparatus rather than directly from paraxial mesoderm
.

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9
Q

Cranial nn. In order

A
I: olfactory 
II: optic
III: oculomotor
IV: trochlear
V: trigeminal
VI: abducens 
VII: facial
VIII: vestibulocochlear
IX: glossopharyngeal 
X: vagus 
XI: spinal accessory 
XII: hypoglossal
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10
Q

Cranial nn. That carry only special sensory fibers

A

. CNI: olfaction from nasal mucosa
. CN II: vision from orbital retina
. CN VIII: hearing from cochlear duct, balance and equilibrium from sensory epithelium in semicircular ducts and vestibule

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11
Q

Cranial nn. That carry only motor fibers

A

. CN III: somatic and visceral motor, extraocular and intraocular mm.
. CN IV: somatic, extraocular mm.
. CN VI: somatic, extraocular mm.
. XI: somatic, trap, SCM, pharyngeal mm.
. XII: somatic, all intrinsic and most extrinsic tongue mm.

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12
Q

Trigeminal n. Ophthalmic division region supplied

A

. Somatic sensory

. Upper face: cornea, scalp, forehead, nose, nasal cavity, paranasal sinuses

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13
Q

CN V maxillary division region supplied

A

. Somatic sensory

. Mid face structures: skin over maxilla, upper lip, maxillary teeth, nasal cavity, maxillary sinuses, palate

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14
Q

CN V mandibular division region supplies

A

. Somatic sensory to lower face structures (skin over mandible, lower lip, temple, mandibular teeth, TMJ, mucosa of oral cavity and tongue)
. Somatic motor: mm. Of mastication

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15
Q

facial nn. Region supplied

A

. Somatic sensory : external ear
. Special sense: taste rom ant. 2/3 tongue
. Somatic motor: mm. Of facial expression
. Visceral motor: lacrimal gland, submandibular and sublingual salivaery glands, mucosa of nasal cavity, hard and soft palates

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16
Q

Glossopharyngeal n. Region supplied

A

. Somatic sensory: post. 1/3 tongue, oropharynx, mucosa of middle ear cavity, auditory tube
. Special sense: Taste from post. 1/3 of tongue
. Visceral sensory: chemoreceptors to carotid body and carotid sinus
. Somatic motor: stylopharyngeus m.
. Visceral motor: parotid gland

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17
Q

Vagus n. Region supplied

A

. Somatic sensory: external ear, larynx, laryngopahrynx, dura
. Special sense: taste from root of tongue and epiglottis
. Visceral sensory: chemo and baroreceptors to aortic body, esophagus, thoracic, and abdominal viscera
. Somatic motor: palatoglossus m., mm. Of pharynx, larynx, and soft palate
. Visceral motor: mucosa of pharynx and larynx, smooth mm. Of pharynx, larynx, thoracic, and abdominal organs, cardiac mm.

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18
Q

Olfactory nerve and pathway

A

. CN I
. Involved in olfaction, carries special sense fibers from nasal mucosa to forebrain
. Nerve fibers pass sup. Through cribiform plate to olfactory bulbs that sit on sup. Surface of cribiform plate
. Bulbs contain sensory neuron cell bodies w/ axons coursing caudally in olfactory tract to forebrain

19
Q

Anosmia

A

. Loss of partial or total sense of smell

. Can occur from blows to head causing tear in nerve that pass through cribiform plate

20
Q

Optic n. And pathway

A

. CN II
. Carries special sense fibers from retina to forebrain
. Considered sensory tract extensions rather than true peripheral nn.
. Paired optic nn. Run caudally from back of eyeball and pass through optic canals to enter neurocranial cavity
. Nn. Merge at optic chasm ant. To sella turcica and some nerve fibers cross to contralateral sides
. Reorganized fibers continue post. From optic chiasm as paired optic tracts that go to sensory nuclei in brain
. Dural sheath is continuous post. W/ cranial dura, fuses w/ sclera ant.

21
Q

Vestibulocochlear n. And pathway

A

. CN VIII
. Carries special sense fibers and connects to multiple brainstem nuclei
. Enter internal acoustic meats of temporal bone and divides into vestibular and cochlear divisions
. Vestibular division innervates special sense epithelium in semicircular ducts and vestibule of inner ear (maintain balance and equilibrium)
. Cochlear division innervates special sense epithelium in cochlear duct of inner ear (hearing)

22
Q

Oculomotor n. And pathway

A

. CN III
. Carries somatic motor and parasympathetic visceral motor fibers that originate in brainstem in separate nuclei
. Courses along lat. wall of cavernous sinus to enter orbit through sup. Orbital fissure
. Provides somatic motor innervation to levator palpebrae superioris m. And extraocular mm. (Sup., inf., and med. rectus, and inf. Oblique)
. Parries parasympathetic fibers to smooth mm. Of orbit (sphincter pupillae, ciliary mm.) from ciliary ganglion
. Sup. Division: to levator palpebrae superioris and sup. Rectus
. Inf. Division: other EOM and parasympathetics

23
Q

Parasympathetic general pathway in head

A

. Preganglionic fibers arise only w/ CN III, VII, IX, and X
. Fibers synapse in one of the parasympathetic head ganglia (ciliary, otic, pterygopalatine, and submandibular)
. Postganglionic fibers course w/ CN V branches to reach target

24
Q

Trochlear n. And pathway

A

. Somatic motor that originates in brainstem
. Courses along lat. wall of cavernous sinus to enter orbit through sup. Orbital fissure sup. To common annular tendon
. Innervates sup. Oblique m.

25
Q

Abducens n. And pathway

A

. Carries somatic motor fibers and originates in brainstem
. Courses lat. to internal carotid a. through cavernous sinus to enter orbit via sup. Orbital fissure and common annular tendon
. Innervates lat. rectus m.

26
Q

Spinal accessory n. And pathway

A

. CN XI
. Somatic motor fibers
. Spinal part and cranial part
. Spinal part: fibers from cervical spinal cord, course sup. To enter skull via foramen magnum and then joins cranial part fibers as they emerge from brainstem
. Spinal and cranial parts merge intracranial and exit skull through jugular foramen then diverge
. Spinal part provides motor to trap and SCM mm.
. Cranial part joints vagus n. In pharyngeal plexus to supply motor to pharynx

27
Q

Hypoglossal n. And pathway

A

CN XII
. Somatic motor fibers that originate in brainstem
. Exit skull via hypoglossal canal, course ant. And pass deep to mylohyoid m. To enter oral cavity
. Provides somatic motor innervation to intrinsic mm. Of tongue and all but 1 extrinsic tongue mm.
. Carries somatic motor fibers to C1 spinal n. That innervates ant. Neck mm.

28
Q

Trigeminal n. And general pathway

A

. Large sensory root and smaller motor root that emerge separately from brainstem
. Nerve merges w/ trigeminal ganglion in middle cranial fossa that contains cell bodies of trigeminal sensory neurons
. At ganglion, sensory fibers split into 3 divisions and motor division continues w/ mandibular division

29
Q

Ophthalmic n. And pathway

A

. Courses along lat. wall of cavernous sinus and enters orbit through sup. Orbital fissure
. Carries general sensory innervation from forehead, upper eyelid, eye, node, nasal cavity, and lacrimal gland

30
Q

Maxillary n. And pathway

A

. V2
. Courses along lat. wall of cavernous sinus and enters pterygopalatine fossa through foramen rotundum
. Carries sensory innervation from temple, skin of cheek, lower eyelid, mucosa of nasal cavity, maxillary sinuses, maxillary definition and gingivae, and palatal mucosa

31
Q

Mandibular n. And pathway

A

. V3
. Somatic sensory and somatic motor fibers enter infratemporal fossa through foramen ovale
. Carries sensory innervation from dura of ant. And middle cranial fossa, external ear, temple, skin, mucosa of cheek and chin, lingual mucosa of tongue, mandibular dentition and gingivae
. Supplies somatic motor innervation to muscles of mastication and a few others derived from pharyngeal arch 1

32
Q

Facial n. Pathway

A

. Composed of somatic motor, parasympathetic visceral motor, special sense, and somatic sensory fibers that originate in/attach to different regions of brainstem
. Courses along skull base, enters internal auditory meatus, and joins w/ geniculate ganglion (contains cell bodies of CN VII sensory neurons)
. Descends through temporal bone in facial canal before exiting the skull via stylomastoid foramen

33
Q

What occurs to facial n. At geniculate ganglion?

A

. Parasympathetic fibers branch off and emerge on intracranial skull base as greater petrosal n. Supplying lacrimal, nasal, and palatal mucosal glands to pterygopalatine ganglion
.

34
Q

Branches of facial n.

A

. Somatic motor branch to stapedius m. Of middle ear cavity
. Chorda tympani n.
. Somatic sensory branches to external ear
. Facial n. Proper emerges from stylomastoid foramen and consists of somatic motor fibers that innervate mm. Of facial expression (parotid plexus) and post. Belly of digastric m. And stylohyoid m.

35
Q

Chorda tympani n.

A

. Courses through middle ear cavity and exits skull via petrotympanic fissure
. Infratemporal fossa joins w/ lingual n. To continue to oral cavity
. Carries parasympathetic visceral motor fibers involved innervating salivary and mucosal glands of tongue and lower jaw to submandibular ganglion
. Carries taste sense fibers from ant. 2/3 of the tongue

36
Q

Lesions of facial n. Can negatively impact ___

A

. Facial expressions
. Salivation
. Tears production
. Taste and/or hearing

37
Q

Glossopharyngeal n. Pathway .

A

. Composed of somatic motor, parasympathetic visceral motor, taste fibers, somatic sensory, visceral sensory that originate from multiple regions brain stem
. Exits skull via jugular foramen and gives off tympanic n. That caries parasympathetic and somatic sensory fibers
. Parasympathetic branches off and remainder courses inf. Through neck

38
Q

Tympanic n.

A

. Enters middle ear cavity through tympanic canaliculus

. Contributes to the tympanic plexus which provides sensory innervation to mucosa of tympanic cavity and auditory tube

39
Q

Facial n. Parasympathetic fiber pathway

A

. Coalesce w/ lesser petrosal n. That emerges from middle ear
. Courses ant. Across middle cranial fossa to exit skull at foramen ovale
. Less petrosal n. Carries fibers to innervate salivary gland
. Fibers synapse at otic ganglion in infratemporal fossa

40
Q

Facial n. Innervation pathways in neck

A

. Somatic motor to stylopharyngeus mm.
. Somatic sensory branches from post. 1.3 tongue, oropharynx, palatine tonsils
. Special sense (taste) branches from post. 1/3 tongue
. Visceral sensory via branches to carotid body and carotid sinus that monitors bp

41
Q

Vagus n. Pathway

A

. Composed of somatic motor, parasympathetic visceral motor, taste fibers, somatic sensory, and visceral sensory fibers that originate from multiple regions of brainstem
. Exits skull through jugular foramen and descends through neck w/in carotid fascial sheath w/ internal jugular v. And internal carotid a.
. Gives off branches to head and neck
. Continues inf. Through neck into thoracic and abdominal cavities and carries parasympathetic and visceral sensory fibers to thoracic and abdominal organs

42
Q

. Branches of CN X in head and neck

A

. General sensory fibers from dura of post. Cranial fossa, external ear, larynx, and laryngopharynx
. Somatic motor fibers to palatoglossus, mm. Of soft palate, pharynx, and larynx
. Visceral motor to smooth mm. And glands of pharynx, larynx, thoracic and abdominal viscera
. Taste fibers to epiglottis and root of the tongue
. Visceral sensory fibers to aortic arch, esophagus

43
Q

Superior laryngeal n.

A

. Branch of vagus n. In neck
. Carries somaticsensory fibers from mucosa of the laryngopharynx and larynx (internal laryngeal branch), and somatic motor fibers to cricothyroid m. (External laryngeal branch)

44
Q

Recurrent laryngeal n.

A

. Loop around R subclavian a. And aortic arch
. Ascend to larynx btw trachea and esophagus to provide motor innervation to remaining laryngeal mm. And general sensory innervation to laryngeal mucosa