UNIT 2: Cranial Nerves Flashcards

1
Q

ascending pathways are

A
  • afferent (sensory) inputs to higher regions of the CNS
  • create cognitive perception of incoming signals
  • guide the creation of execution of motor responses to enviro stimuli
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2
Q

3 neurons of the ascending pathways

A

primary neuron (spinal or cranial nerve), secondary neuron, tertiary neuron

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3
Q

descending pathways are

A
  • efferent (motor) outputs from cortex and brainstem to somatic and visceral motor neurons
  • execution of motor activity
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4
Q

2 neurons of the descending pathways are

A

upper motor neuron (corticospinal or corticobular) and lower motor neuron (spinal or cranial nerve)

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5
Q

describe the primary neuron of the afferent pathway

A
  • “nerve” (outside the brain)
  • dendrites innervate end receptor cells
  • cell body is typically located at a different location in a ganglion
  • axon extends to synapse in the sensory nucleus in the brain stem
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6
Q

describe the secondary neuron of the afferent pathway

A
  • cell body in the brainstem nucleus that is associated w the nerve
  • axon extends to the thalamus… the sensory relay station
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7
Q

describe the tertiary neuron of the afferent pathway

A
  • cell body in the thalamus
  • axon extends to the primary sensory cortex (most often in the postcentral gyrus of the parietal lobe)
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8
Q

describe the somatic motor pathway of the efferent pathway

A
  • upper motor neuron has a cell body in the motor cortex
  • axon extends to the level of the brainstem
  • motor nucleus is located in the brainstem
  • the lower motor neuron has the cell body in the brainstem nucleus which is associated w a nerve
  • axon extends to and innervates muscle fibres an/or glans
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9
Q

describe the visceral motor pathway of the efferent pathway

A
  • for the upper neuron, input comes from other nuclei like the limbic system
  • then travels to brainstem to the lower motor neuron
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10
Q

most cranial nerves provide bilateral innervation because

A

gives some redundancy in especially important areas like the face and throat for example

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11
Q

describe spinal nerves

A
  • contain both afferent and efferent fibres
  • project from the spinal cord
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12
Q

cervical spinal nerves correspond to

A

neck, shoulder, arms

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13
Q

thoracic spinal nerves correspond to

A

upper trunk

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14
Q

lumbar and sacral spinal nerves correspond to

A

lower trunk, legs, feet

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15
Q

how many cranial nerves are there

A

12

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16
Q

the cranial nerves project to and from where? (name exceptions)

A

brainstem, except for CNI and CNII

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17
Q

how are cranial nerves more complex then spinal nerves

A
  • can be motor, or sensory, or both
  • motor and sensory can serve somatic and/or autonomic functions
  • can serve general or special end receptors
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18
Q

What part of the embryo develops into our face and airway and which part doesn’t?

A
  • the mesoderm develops into somites which eventually make up most of the sensory and motor tissue… except …
  • most of our face and neck do not dev from somites - they dev from branchial arches
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19
Q

describe how a cranial nerve is a functional unit

A

nerve + brainstem nucleus + peripheral target = functional unit

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20
Q

CN 1

A
  • olfactory nerve
  • sensory
  • mediates sense of smell
  • olfactory sensors in mucous membrane of nasal cavities
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20
Q

CN II

A
  • optic nerve
  • sensory
  • vision = sensory photoreceptors in retina
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21
Q

CN III

A
  • oculomotor nerve
  • motor
  • most extrinsic ocular muscles
  • light and accommodation reflexes of pupil constriction and focus
  • oculomotor nuclei in midbrain
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22
Q

CN III, CN IV, CN VI are all involved in

A

moving our eyes and controlling pupils and lens

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23
Q

CN IV

A
  • trochlear nerve
  • motor
  • turning eyes down and in
  • trochlear motor nucleus in midbrain
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24
Q

CN VI

A
  • abducens nerve
  • motor
  • abduct eye (move laterally away from midline)
  • abducent motor nucleus in pons
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25
Q

CN V

A
  • trigeminal
  • motor and sensory
  • somatic sense for the face and oral cavity
  • muscles of masstication, tensor veli palatini (soft palate), and tensor tympani (ear drum)
  • 3 divisions
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26
Q

3 divisions of CN V

A

Ophthalmic, maxillary, mandibular

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27
Q

describe the ophthalmic division of CN V

A
  • sensory
  • links to the skin of the upper face, forehead, scalp, cornea, iris, conjunctiva, upper eyelid, nasal cavity mucosa, meninges
28
Q

describe the maxillary division of CN V

A
  • sensory
  • links to the lower eyelid, skin of the nose, maxilla, upper teeth and gums, upper lid, buccal mucosa, maxillary sinuses
29
Q

describe the mandibular division of CN V

A
  • sensory and motor
  • links to the mandible, lower teeth and gums, anterior 2/3 of the tongue, lower cheek and chin, temporomandibular joint, external auditory meatus and pinna of the ear, muscles of mastication (prioprioception)
30
Q

what are the 4 nuclei of CN V

A

mesencephalic nucleus, principal sensory nucleus, spinal trigeminal nucleus, trigeminal motor nucleus

31
Q

the mesencephalic nucleus of CN V is in the ____ and has ____ inputs from the _____ muscles

A
  • midbrain
  • proprioceptive
  • mandibular
32
Q

the principal sensory nucleus of CN V is in the ____ and has ____ inputs, critical for ____

A
  • pons
  • cutaneous and tactile
  • speech dev
33
Q

the spinal trigeminal nucleus of CN V is in the ____ and has ____ inputs

A
  • medulla
  • aka nucleus of the spinal tract
  • noxious and thermal inputs
34
Q

the trigeminal nucleus of CN V is in the ____

A

pons

35
Q

CN VII

A
  • Facial nerve
  • sensory and motor
  • facial muscles + stapedius muscle (middle ear) and suprahyoid muscles
  • lacrimal gland, submandibular and sublingual salivary glands, mucous membranes of nose and palate
  • taste from 2/3 of the tongue
  • sensation from the external auditory meatus, external surface of the tympanic membrane, skin behind the ear
36
Q

facial motor nucleus of CN VII is in the

A

pons

37
Q

superior salivatory nucleus of CN VII is in the

A

pons

38
Q

Nucleus of the spinal tract of CN VII is in the

A

medulla

39
Q

solitary tract nucleus of CN VII is in the

A

medulla

40
Q

CN VIII

A
  • vestibulocochlear
  • sensory
  • hearing and vestibular sense
  • organs of hearing and vestibular sensation in the inner ear
41
Q

cochlear and vestibular nuclei of CN VIII is located at

A

pontomedullary junction (where pons and medulla come together)

42
Q

CN IX

A
  • Glossopharyngeal
  • sensory and motor
  • taste from posterior 1/3 of tongue and soft palate
  • touch, pain, temp from posterior 1/3 of tongue, faucial pillars, upper pharynx, middle ear
  • barosensation and chemosensation in internal carotid artery (blood press and oxygenation)
  • pain and temp from skin of the ear
  • stylopharyngeus muscle
  • parotid gland (salivary flow)
43
Q

the solitary tract nucleus of CN IX is in the

A

medulla

44
Q

the nucleus of the spinal tract for CN IX is in the

A

medulla

45
Q

the nucleus ambiguus of CN IX is in the

A

medulla

46
Q

the inferior salivatory nucleus of CN IX is in the

A

medulla

47
Q

CN X

A
  • Vagus
  • sensory and motor
  • extensive nervous supply thru head, neck, trunk
  • pain, touch, temp from tympanic membrane, pinna, and external auditory meatus
  • pain, touch and temp from pharynx, larynx, thoracic, and abdominal viscera, esophagus, and bronchi
  • barosentation and chemosensation from aorta
  • taste from epiglottis
  • parasymp innervation of intestines, pancreas, stomach, esophagus, trachea, bronchial smooth muscle and mucosal glads, kidney, liver, heart
  • soft palate, pharynx, and larynx
48
Q

the nucleus of the spinal tract of CN X is in the

A

medulla

49
Q

the nucleus of the solitary tract nucleus of CN X is in the

A

medulla

50
Q

the nucleus of the dorsal motor nucleus of vagus of CN X is in the

A

medulla

51
Q

the nucleus of the ambiguus of CN X is in the

A

medulla

52
Q

CN XI

A
  • accessory
  • motor
  • sternocleidmastoid and trapezius
  • neck and shoulder movements
53
Q

nucleus ambiguus of CN XI is in the

A

medulla

54
Q

CN XII

A
  • Hypoglossal
  • motor
  • all muscles of the tongue except 1
55
Q

hypoglossal nucleus of CN XI is in the

A

medulla

56
Q

MRI

A
  • magnetic resonance imaging
  • shows change in soft tissue
  • costly, not first step
57
Q

fMRI

A
  • functional magnetic resonance imaging
  • looking for change in blood flow - more used in research
58
Q

DTI

A

Diffusion tensor imaging
- look at communication - aka association and commissural fibres

59
Q

CT

A

computed tomography
- cheaper cousin of MRI
- radiation
can show a stoke usually via disruption of blood, some bone changes, and used to show tumours

60
Q

PET

A
  • Positron emission tomography
  • like a CT but w radioactive traser to see blood flow
61
Q

hemorrhages w/i arterial or venous systems causes

A

a vascular pathology, blood to pool w/i neural tissue, causing a disruption of blood supply beyond the point of hemorrhage

62
Q

ischemic stroke is

A

a vascular pathology, disruption of blood supply leading to ischemia (dec oxygen), and evetually an infarct (dead brain tissue)
- thrombus = blockage in a vessel
- embolus - travelling clot or fragment of thrombus

63
Q

Aneurysms are

A

a vascular pathology, balloon like distension of arterial wall, risk for rupture and hemorrhage

64
Q

arteriovenous malformation (AVM) is

A

a vascular pathology, congenital tangles of arteries and veins, risk for growth and rupture

65
Q

amyotrophic lateral sclerosis is

A

a degenerative condition, disease of motor neurons - cell bodies in spinal cord and CN nuclei and precentral pyrus can be affected

66
Q

multiple sclerosis is

A

a degenerative condition, degeneration of myelin sheath on axons; both sensory and motor

67
Q

parkinsons disease is

A

a degenerative condition, disease of basal ganglia, degeneration of dopamine producing neurons in substantia nigra

68
Q

neoplasms/tumors are

A

a degenerative condition, abnormal proliferation of cells, typically in myelin or glial cells