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Neuroanatomy > Unit 4: Cranial Nerves pg 121 - 137 > Flashcards

Unit 4: Cranial Nerves pg 121 - 137 Flashcards

1
Q

Neuron cell bodies located in the trochlear nucleus are at the level of the

A

Inferior colliculus in midbrain

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2
Q

Lesions of the trochlear nerve (CN IV) are

A

Unusual and difficult to detect

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3
Q

Action of the superior oblique muscle:

A
  • Depress
  • Abduct
  • some Intorsion (medial rotation)

…Of the eye.

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4
Q

The superior oblique muscle is innervated by

A

Trochlear nerve (CN IV)

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5
Q

Abducens nerve (CN VI) originates from abducens nucleus in the ______ within the _______

A
  • Lower pons

- facial colliculus in the floor of the IV ventricle

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6
Q

What innervates the lateral rectus muscle?

A

Abducens nerve (CN VI)

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7
Q

Unilateral lesion of VI nerve or nucleus results in

A
  • flaccid paralysis of ipsilateral lateral rectus muscle

- inability to abduct the ipsilateral eye

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8
Q

Medial strabismus = esotropia

A

Eye is strongly adducted

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9
Q

Diplopia

A

Double-vision

Occurs in medial strabismus (esotropia) because both eyes cannot look at the same target

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10
Q

Oculomotor nerve (CN III) originates from

A

Oculomotor nuclear complex in the midbrain at the level of superior colliculus

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11
Q

Oculomotor nuclear complex contains what nucleus?

A

Edinger-Westphal (E-W) nucleus

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12
Q

Edinger-Westphal (E-W) nucleus is what kind of neurons

A

Preganglionic parasympathetic neurons (autonomic nucleus)

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13
Q

Superior rectus and inferior rectus, medial rectus, inferior oblique and elevator palpebrae superioris are innervated by

A

CN III

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14
Q

Action of superior rectus and inferior rectus, medial rectus, inferior oblique and elevator palpebrae superioris

A
  • Adduction

- Vertical movement

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15
Q

Preganglionic parasympathetic neurons (E-W neurons) innervate

A

Postganglionic parasympathetic neurons of the ciliary ganglion

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16
Q

Postganglionic parasympathetic neurons of the ciliary ganglion innervate

A
  • Constrictor pupillae

- Ciliary muscles

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17
Q

Pupillary light reflex

A

Reflexive constriction of both pupils in response to increase in light intensity on the retina

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18
Q

What do you expect to see in pupillary light reflex?

A

Contraction of the pupil of the stimulated eye AND contraction of the non-stimulated eye

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19
Q

Afferent limb of pupillary light reflex is (and trace the pathway)

A

CN II

Requires visual p/way: optic nerve —> optic tract —> superior brachium —> synapse on pretectal nucleus —> send axons to both left and right E-W nuclei via posterior commisure

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20
Q

Efferent limb of the pupillary light reflex is (and trace the pathway)

A

CN III formed by the right and left Edinger-Westphal nuclei

Send axons to ciliary ganglia —> innervate sphincter pupillae muscles of both eyes

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21
Q

When you shine light in right eye and you expect to see a response in the right eye, its called what kind of response?

A

Direct pupillary light response (pupillary constriction of the eye)

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22
Q

When you shine light in right eye and expect to see a response in the left eye, it’s called what?

A

Consensual (indirect) pupillary light response: pupillary constriction of non-stimulated eye

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23
Q

Oculomotor nerve is at the level of the

A

Superior colliculi (upper midbrain)

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24
Q

Reflexive actions that occur when one’s gaze is shifted from distance target to a nearer target

A

Accommodation or accommodation-convergence reflex

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25
Q

Convergence eyes is by the contraction of

A

Both medial recti muscles

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26
Q

Pupillary constriction of both eyes makes contraction of

A

Both sphincter pupillae muscles

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27
Q

Accommodation of both lenses uses the contraction of

A

Both ciliary muscles

This will increase convexity of the lenses and allow for focus on a near target

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28
Q

The neural pathway for the accommodation or accommodation-convergence reflex involves

A

CN II —> Optic tract —> LGB

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29
Q

Afferent limb of the accommodation or accommodation-convergence reflex

A

CN II

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30
Q

Efferent limb of accommodation or accommodation-convergence reflex

A

CN III

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31
Q

Unilateral lesion of CN III results in

A
  1. Flaccid Paralysis (because damage to LMN fibers) of all ipsilateral mm innervated by CN III
  • Superior and inferior rectus
  • Medial rectus
  • Inferior oblique
  • Levator palpebrae superioris

—> Inability to adduct the eye and move eye vertically
—> lateral (external)strabismus would occur = eye strongly abducted

  1. Ptosis = drooping of superior palpebrum (upper eyelid)
  2. Loss of innervation to ciliary ganglion
    —> no pupillary light reflex (direct nor consensual) response in ipsilateral eye (because motor efferent limb is interrupted)
    —> dilation of pupil in ipsilateral eye
    —> loss of accommodation of lens of ipsilateral eye
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32
Q

Weber’s Syndrome can be cause from

A

Vascular lesion of the anterior midbrain (basal part of cerebral peduncle)

Note: interrupting fibers of pyramidal system probably as well because cerebral crus is located here as well. The descending pyramidal fibers will be affected

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33
Q

Weber’s syndrome interrupts

A

Ipsilateral CN III and descending motor control fibers of cerebral crus (pyramidal system)

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34
Q

Weber’s syndrome results in

A

Ss/SXs of a CN III lesion of ipsilateral eye

UMN lesion:

  • contralateral spastic hemiplegia
  • contralateral spastic paralysis of muscles of facial expression of the contralateral lower 1/2 of the face and muscles of the contralateral tongue 👅
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35
Q

Trigeminal motor nucleus is located in

A

Upper pons

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36
Q

LMNs of V nerve receive what kind of innervation

A

Bilateral CB/CN innervation (review from exam 4)

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37
Q

CN V fibers exit the pons to innervate

A
  • Muscles of mastication
  • Tensor tympani m
  • Tensor veil palatini m
  • Mylohyoid m
  • Anterior belly digastric m
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38
Q

Interruption of the motor fibers of the V nerve results in

A

Flaccid paralysis and eventual atrophy = deviation of the mandible

Note: Peripheral nerve lesion or CN nerve lesion are LMN lesions which result in flaccid paralysis. (UMN lesion result in spastic paralysis)

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39
Q

Lesion of the LEFT V nerve, the mandible will deviate towards what side?

A

LEFT side, the lesioned (paralyzed) side

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40
Q

CN VII (Facial) sensory fibers exit brainstem with CN VII preganglionic parasympathetic neurons as the

A

Nervus intermedius

41
Q

Peripheral processes of the geniculate ganglion (primary neuron cell bodies of CN VII) for general S-S neurons innervate:

A
  • Skin of external ear
  • Wall of external auditory canal
  • External surface of tympanic membrane
42
Q

Trochlear and Abducens nerve fibers are entirely composed of ________.

43
Q

Axons of abducens nerve exit ______ surface of the brainstem at the ________.

A
  • ventral surface

- pontomedullary junction

44
Q

Where in the pontomedullary junction is abducens nerve located?

A

Most medially

From medial to lateral, the cranial nerves in the pontomedullary junction are 6,7,8

45
Q

Cranial nerve III/ oculomotor nerve contains what kind of fibers?

A

contains LMNs & autonomic preganglionic parasympathetic neurons

46
Q

Axons of oculomotor nerve exit the brain stem at ________.

A

Interpeduncular fossa

47
Q

Peripheral processes of the geniculate ganglion (primary neuron cell bodies of CN VII) for gustatory neurons innervate

A
  • chorda tympani

- greater petrosal nerve to the palate — taste receptors

48
Q

Central processes of General SS Neurons of CN VII enter brainstem, join spinal trigeminal tract and synapse in the

A

2˚ Spinal trigeminal nucleus

49
Q

General SS Neurons of CN VII terminate in where in the cortex

A

1˚ somatosensory cortex

50
Q

Central processes of gustatory neurons of CN VII enter brainstem and terminate in the

A

Rostral part of the solitary nucleus

51
Q

Two types of motor neurons/fibers of the facial nerve:

A
  • Somatomotor neurons (LMNs)

- preganglionic parasympathetic neurons

52
Q

Afferents to the CN VII motor nucleus include

A
  • Corticobulbar/C-N fibers (UMN)
  • superior olivary nucleus for reflexive contraction of stapedius in response to loud noise
  • SS input from sensory nuclei of trigeminal nerve CN V for stimulation of corneal reflex (“blink” reflex)
53
Q

Preganglionic parasympathetic neurons of CN VII comprise 2 nuclear groups in the lower pons

A
  1. Superior salivatory nucleus

2. Lacrimal nucleus

54
Q

Fibers of the Superior salivatory nucleus are distributed in

A

Chorda tympani

55
Q

Fibers of Superior salivatory nucleus (preganglionic parasympathetic neurons) terminate in ______ ganglion on what kind of neurons

A

Submandibular ganglion; postganglionic parasympathetic neurons

56
Q

What do you expect in a full compression of all unilateral (CN VII) fibers

A
  • paralysis of all upper and lower ipsilateral facial muscles
  • paralysis of ipsilateral stapedius m —> hyperacusis
  • diminished taste sensation of anterior 2/3 tongue
  • decreased salivation —> dry mouth
  • loss of direct & consensual corneal reflex of ipsilateral eye
  • decreased /loss of lacrimation: no lacrimation, loss or decreased ability to blink ipsilaterally = increased contralateral blinking
57
Q

IX nerve sensory components (3)

A
  1. S-S neurons
  2. Gustatory neurons
  3. General visceral afferent neurons (GVAs)
58
Q

Postganglionic parasympathetic neurons that terminated in submandibular ganglion provide secretomotor innervation to:

A
  • submandibular gland
  • sublingual gland
  • lingual gland
  • labial gland
59
Q

The fibers of the lacrimal nucleus are distributed in

A

Greater petrosal nerve

60
Q

Fibers of lacrimal nucleus terminate in _____ ganglion on what kind of neurons

A

Pterygopalatine ganglion (sphenopalatine ganglion) on postganglionic parasympathetic neurons

61
Q

Postganglionic fibers that terminated on pterygopalatine ganglion provide secretomotor innervation to

A
  • nasal glands
  • palatine glands
  • lacrimal glands
62
Q

Common disturbance of CN VII is a condition called

A

Bell palsy

63
Q

Bell Palsy could be caused by

A

increased pressure on VII nerve

  • as it traverses facial canal in petrous temporal bone or
  • as the motor root travels through the parotid gland
64
Q

Glossopharyngeal nerve (CN IX) 3 sensory neurons

A
  1. S-S neurons
  2. Gustatory neurons
  3. General visceral afferent neurons (GVAs)
65
Q

S-S afferents of the IX nerve serve as the afferent limb of the

A

Gag reflex

66
Q

Efferent limb of the gag reflex include which nerves

A 
CN X (palate and pharynx mm)
CN XII (tongue mm)
CN V (mastication mm)
CN VII (facial expression mm)
67
Q

Peripheral processes of CN IX distribute to the following areas

A
  • posterior 1/3 tongue 👅
  • upper pharynx
  • tympanic cavity
  • Eustachian tube
67
Q

Peripheral process of CN IX gustatory neurons distribute through

A

Lingual branches of IX nerve to taste receptors on posterior 1/3 tongue 👅

69
Q

Peripheral processes of GVAs (general visceral afferent neurons) of IX nerve distribute to specialized receptors in the:

A 
Carotid sinus (baro)
Carotid body (chemo)
70
Q

What do GVAs (general visceral afferent) do?

A

Reflex regulation of cardiovascular, respiratory, alimentary function

70
Q

Carotid sinus is what kind of receptor

A

Baroreceptor

71
Q

Carotid body is what kind of receptor

A

Chemoreceptor

72
Q

CN IX 2 types of motor components:

A

LMNs and Autonomic neurons

73
Q

Somatomotor neuron fibers distributed through pharyngeal branches of CN IX to supply:

A

Ipsilateral stylopharyngeus m

74
Q

Somatomotor neurons of CN IX receive bilateral

A

CB/CN innervation

75
Q

Preganglionic parasympathetic neurons of CN IX have cell bodies that comprise what nucleus?

A

Inferior salivatory nucleus (medulla)

76
Q

Unilateral lesion of CN IX would lead to:

A
  • loss of gag reflex (when ipsilateral posterior 1/3 tongue/upper pharynx stimulated)
  • Decreased taste sensation
  • Decreased salivation
  • Paralysis of ipsilateral stylopharyngeus muscle
77
Q

Vagus nerve (CN X) has 3 types of sensory fibers:

A
  1. S-s neurons
  2. Gustatory neurons
  3. General visceral afferent neurons
78
Q

Motor component for CN X includes 2 types:

A

LMNs and preganglionic parasympathetic neurons

79
Q

Peripheral processes of the S-S neurons of Vagus Nerve innervate:

A
  • Some external ear
  • Portion of external auditory canal (these 2 bullet points along with C2, CN VII, V3 of CN V)
  • Lower pharynx
  • Larynx
  • Upper esophagus
80
Q

Peripheral processes of gustatory neurons of CN X (Vagus) innervate

A

Epiglottis

81
Q

General visceral afferent neurons (GVAs) of CN X innervate:

A
  • Baroreceptors in the aortic arch
  • Chemoreceptors in the aortic arch
  • Receptors in hollow organs through thoracic and abdominal cavities: GI tract through transverse colon
82
Q

Somatomotor neuron cell bodies of CN X are located in nucleus ambiguus and emerge from brainstem as either/or:

A
  • Part of vagus nerve or

- as cranial root of spinal accessory nerve

83
Q

Somatomotor neuron fibers of the X nerve supply:

A
  • all muscles of palate (EXCEPT tensor veil palatini)
  • m of pharynx (EXCEPT stylopharyngeus)
  • m of larynx
  • upper esophagus
84
Q

Postganglionic fibers of CN X are distributed to visceral effector cells:

A
  • cardiac m
  • smooth m
  • gland cells
85
Q

Unilateral lesion of vagus nerve would result in:

A
  • ipsilateral paralysis of all muscles of palate (except
    tensor veli palatine), all muscles of pharynx (except stylopharyngeus), muscles of the larynx, & upper esophagus
  • during phonation, uvula will deviate AWAY from lesioned side

Vocal fold dysfunction:

  • some difficulty swallowing (dysphagia)
  • some difficulty breathing (dyspnea)
  • hoarseness of voice
86
Q

bilateral lesion of vagus nerve:

A

Rare

  • paralysis of laryngeal and pharyngeal muscles

Could be fatal

87
Q

Spinal accessory nerve CN XI supplies what?

A
  • sternocleidomastoid m

- trapezius m

88
Q

Accessory nerve (CN XI) has two roots

A

Spinal root

Cranial root

89
Q

Cell bodies of CN XI spinal root are located in ____ nucleus in the:

A

Spinal accessory nucleus; ventral horn spinal cord segments C1-C5

90
Q

Cell bodies of CN XI cranial root located in

A

Nucleus ambiguus

91
Q

At what foramen does the cranial roof CN XI join the vagus nerve and explain what it does

A

Enters Jugular foramen and provides X nerve innervation to muscles of palate and larynx

92
Q

Inferior to jugular foramen, Spinal root of XI provides motor innervation to

A
  • SCM

- Trapezius

93
Q

In regards to CN XI, unilateral Corticospinal/UMN lesions result in

A

Paralysis of contralateral trap and SCM muscles

Because contralateral corticospinal innervation to LMNs of spinal root of CN XI

94
Q

In regards to CN XI, unilateral peripheral XI nerve lesions result in

A

Ipsilateral trap and SCM paralysis

95
Q

Hypoglossal nerve XII has LMNs fibers distributed to innervate:

A

All ipsilateral tongue muscles EXCEPT palatoglossus

96
Q

Unilateral lesion of XII nerve results in

A

Paralysis of all ipsilateral tongue muscles

👅 will deviate towards the lesioned/paralyzed side

97
Q

CN XI is associated with what foramen?

A

Jugular foramen

98
Q

Unilateral Corticospinal/UMN lesions will result in what kind of deficit in regards to XII

A

Paralysis of contralateral tongue muscles (like CN XI)

Tongue will deviate toward the lesioned side (paralyzed side).

Neuroanatomy (21 decks)

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