Cranial Nerves Flashcards
(123 cards)
1
Q
Where are cell bodies for cranial nerves housed?
A
-Within the CNS
1
Q
What system are Cranial Nerves part of?
A
PNS
-Cranial nerves leave the skull to innervate systems outside of bony structures of the skull
2
Q
Where are spinal nerve cell bodies located?
A
CNS
3
Q
How many Cranial Nerves are there?
A
12
4
Q
What are the MAIN functions of the Cranial Nerves?
A
Serve function largely for head and neck (some descend into torso)
5
Q
How are the Cranial Nerves labelled?
A
1-12 based upon coronal to caudal/head to tail/front to back
6
Q
In injury, you see symptomology and clusters of symptoms based on…
A
absence or presence of cranial nerve function
7
Q
Optic Nerve II
A
Nerve transmitting sensory information from eyes to visual cortex at back of head
8
Q
Path of transmission from RIGHT eye to visual cortex?
A
- Light hits eye through pupil into retina
- Light comes from left visual field, hits right half of the retina in BOTH eyes
- At retina we sort the information
- Light travels through the right optic nerve in the right eye
- Light travels through the right optic tract
- Light reaches right visual cortex
9
Q
Path of transmission from LEFT eye to visual cortex?
A
- Light hits eye through pupil into retina
- Light comes from left visual field, hits right half of the retina in BOTH eyes
- At retina we sort the information
- Light travels through the left optic nerve in the right eye
- Light crosses the midline of the brain at the optic chasm to cross over
- Light travels in the right optic tract
- Light is delivered to Right side visual cortex
10
Q
What is Visual Field?
A
-The source of light; not the anatomical structure of the eye
-Functional need
11
Q
Light travels in ___ lines
A
straight
12
Q
True or false: Our brains deal with opposite sides of the body
A
True
-Right hand controlled by left brain, vice versa
-Crossing of symptoms is persistent in most neural structures including vision
13
Q
Information from our eyes go to ___ visual cortex
A
Contralateral (opposite)
14
Q
Where does crossing of information in the visual pathway occur?
A
The Optic Chiasm
15
Q
How can we piece together where a visual deficit may occur?
A
I.e. if I cover the right eye, I am blind in the right eye and all information is lost. The same would happen if I severed the right optic nerve.
-If you lose visual regard in one field (left) and can’t see anything to the left of your nose, you may have damaged the optic tract; but you still have visual regard to the other side of the body
-Both eyes are receiving information, just from one half of the body
16
Q
What are the 3 nerves involved with motor function of the eye?
A
-Oculomotor Nerve III
-Trochlear Nerve IV
-Abducens Nerve VI
17
Q
Oculomotor Nerve III
A
-Moves eye up/down, medial
-Raises upper eyelid
-Constricts pupil
18
Q
How can you identify oculomotor nerve III deficit?
A
-If the pupils don’t constrict when a light is shown
-Can’t turn eyes inward
-Can’t raise upper eyelid
19
Q
Trochlear Nerve IV
A
-Moves eye medially and downward (toward nose)
20
Q
Abducens Nerve VI
A
-Abducts eye (outward rotation of eye)
21
Q
Which two nerves serve the face?
A
-Trigeminal nerve V
-Facial nerve VII
22
Q
Trigeminal Nerve V is broken into what divisions?
A
3 divisions:
-Opthalmic
-Maxillary
-Mandibular
23
Q
Trigeminal Nerve V
A
-Largely a Sensory nerve to most of the face/head
-Taste portion of tongue
-Somatosensation front 2/3 of tongue
-Ability to sense what we are touching with our tongue
-We can understand where the bolus is located in mouth, texture, to appropriately swallow
24
What is the motor root of the Trigeminal Nerve V involved with?
Muscles of mastication (chewing)
25
Trigeminal Nerve V relation to Chorda Tympani
-When we get inflammatory response in ear from infection, we get symptomology associated with facial and trigeminal nerve as this is near where the inflammation is happening
26
Facial Nerve VII
-Largely Motor Nerve
-Serves function of facial expression, muscles of facial expression
27
What is the function of the Parasympathetic motor portion of Facial Nerve VII?
-Deals with some parasympathetic glands
-Controls things like saliva, tears, etc
28
What is the function of the special sensory (chords tympani) portion of Facial Nerve VII?
-Taste to front 2/3 of tongue
-Important for what we eat and swallow so it isn't nauseating
29
What is the function of the Somatic Sensory portion of Facial Nerve VII?
Inner ear canal sensory
-tactile sensory information form inner ear canal (i.e. wiggling tip in ear)
30
What is Bell's palsy?
A disorder related to the facial nerve
31
What do you see with Bell's palsy?
-Smoothing of forehead
-Inability to close eyelid
-Drooping of mouth corner
-Paralysis in one side of face
32
Stroke vs. Bell's palsy
-Stroke would see more lower face affected thanupper
-Stroke would not have tests deficits/involvement
-No gland involvement in stroke
-Sensory involvement specific to facial nerve interaction
-Stroke is CNS, Bell's palsy is PNS
-Flaccid paralysis in muscle for Bell's palsy. spastic paralysis for Stroke
33
Effects of Bell's palsy?
Motor adaptations occur and can lead to being more dominant on one side of the face for motor control
34
Ramsay Hunt Disease
-"Chicken Pox" rash in inner ear
-Re-emergence of virus from previous life
-More persistent deficits
-Virus damages the neurons
35
Which Cranial Nerves serve the tongue?
-Trigeminal Nerve V
-Facial nerve VII
-Glossopharyngeal Nerve IX
-Hypoglossal Nerve XII
-They are clustered because they play a role in function of the tongue, feeding and tasting!
36
Glossopharyngeal Nerve IX
-Taste and somatosensation from back 1/3 of tongue
37
Hypoglossal Nerve XII
-Muscles of the tongue/movement
-motor control of the tongue
38
Olfactory Nerve I (Components, Structures Innervated, Function)
-Special Sensory
-Olfactory Epithelium (nasal cavity)
-Smell
39
Optic Nerve II (Components, Structures Innervated, Function)
-Special Sensory
-Retina
-Vision
40
Oculomotor Nerve III: Somatic Motor (Components, Structures Innervated, Function)
-Extraocular muscles (4), levator palpebrae
-Move eyeball, open eyelid
41
Oculomotor Nerve III: Parasympathetic (Components, Structures Innervated, Function)
-Pupillary Constrictor muscle and ciliary muscle
-Constrict pupil, accomodate lens
42
Trochlear Nerve IV (Components, Structures Innervated, Function)
-Somatic motor
-Extraocular muscle (superior oblique)
-Move eyeball
43
Trigeminal Nerve V: Somatic Sensory (Components, Structures Innervated, Function)
-Face, scalp, teeth, lips, front of tongue
-Somatosensation from face and head
44
Trigeminal Nerve V: Somatic Motor (Components, Structures Innervated, Function)
-Muscles of mastication
-Move jaw
45
Abducens nerve VI (Components, Structures Innervated, Function)
-Somatic motor
-Extraocular muscle (lateral rectus)
-Move eyeball
46
Facial nerve VII: Somatic Motor (Components, Structures Innervated, Function)
-Facial muscles, stylohyoid part of figastric and stapedius muscles
-facial expression, swallowing, hearing
47
Facial nerve VII: Special Sensory (Components, Structures Innervated, Function)
-Front 2/3 of tongue
-Taste
48
Facial nerve VII: Parasympathetic (Components, Structures Innervated, Function)
-Salivary, lacrimal nasal glands
-Salivation, tears
49
Facial nerve VII: Somatic Sensory (Components, Structures Innervated, Function)
-External ear canal
-Somatosensation from ear canal
50
Auditory-Vestibular (Vestibulocochlear) nerve VIII (Components, Structures Innervated, Function)
-Special sensory
-cochlea, semicircular canals, utricle and saccule or inner ear
-Hearing, Vestibular sensation
51
Glossopharyngeal Nerve IX: Special Sensory (Components, Structures Innervated, Function)
-Back 1/3 of tongue
-Taste
52
Glossopharyngeal Nerve IX: Parasympathetic (Components, Structures Innervated, Function)
-Parotid Gland
-Salivation
53
Glossopharyngeal Nerve IX: Somatic Sensory (Components, Structures Innervated, Function)
-Pharynx, palate, back 1/3 of tongue, carotid sinus/body, middle/external ear
-Somatosensation, BP, Blood O2
54
Glossopharyngeal Nerve IX: Somatic Motor (Components, Structures Innervated, Function)
-Stylopharyngeus muscle
-Swallowing (assist)
55
Vagus Nerve X: Special Sensory (Components, Structures Innervated, Function)
-Back of throat
-Taste
56
Vagus Nerve X: Parasympathetic (Components, Structures Innervated, Function)
-Viscera or thorax and abdomen
-HR, bronchi constriction, digestion
57
Vagus Nerve X: Somatic Sensory (Components, Structures Innervated, Function)
-Larynx, dura mater, ear, thoracic and abdominal viscera
-Somatosensation
58
Vagus Nerve X: Somatic Motor (Components, Structures Innervated, Function)
-Muscles of pharynx and larynx
-Swallowing, vocalizing
59
Spinal Accessory Nerve XI (Components, Structures Innervated, Function)
-Somatic motor
-SCM, trapezius
-Movement of head, neck, shoulder
60
Hypoglossal Nerve XII (Components, Structures Innervated, Function)
-Somatic Motor
-Muscles of tongue
-Tongue movement
61
Spinal Cord
-organized into "segments"
-runs from base of skull to above tailbone (shorter than vertebral column)
-Gives rise to spinal nerves (PNS)
62
Where does the Spinal cord run to, and why?
About L2
-The SC stops growing/elongating before your long bones do
-Spinal column continues growing with bones to support leverage structure of legs and arms
63
Cauda Equina is part of what system?
PNS
64
What are the segments in the SC based on?
Where the spinal nerve exits the vertebral column
65
Spinal nerves in Cervical Region
-Pass through cervical Segments of the vertebral columns
66
Spinal nerves in Lumbar Region
-Pass through Lumbar Segments of the vertebral columns
-L1 to L5 spinal nerves come out and nerves arise through the part of the cord known as the lumbar segment
67
Where are Sacral and Coccygeal segments located?
-near thorax
-These spinal nerves run a fair distance within the column before exiting
68
Where does the Lumbar segment locate?
-Sits closer to Thoracic vertebrae
69
What is the clump of spinal nerves running within the vertebral column called?
Cauda Equina ; a peripheral nerve bundle
70
True of False: all nerves run down the vertebral column, not the spinal cord though.
True
71
Why is Cauda Equina part of PNS?
It is only contained within the vertebral column because of idiosyncrasy of growth stopping in one system but continuing in the other
72
What are enlargements in the SC?
"Swelling" of segments
73
Why do we have enlargements in our SC?
-These are where our major plexi are
-We need more tissue in our NS supporting things coming out of bodies such as our arms and legs
-We have more we need to control and receive information from, therefore more part of the SC needs to be associated with arms (cervical) and legs (lumbosacral)
74
Where are the two possible enlargements in our SC?
-Cervical enlargement
-Lumbosacral enlargement
75
Why is there 1 more Cervical segment than Cervical vertebrae?
-The first segment (C1) is associated with Cranial Nerve I which exists in the vertebral column above the cerebral vertebrae
-another idiosyncrasy
-8 Cervical Segments, for 7 Cervical Vertebrae
76
In a cross section of the spinal cord, where is Grey and White matter located?
Grey Matter: Central, butterfly shape
White Matter: Peripheral
77
Why do we use the term "Dorsal" rather than "Posterior"?
Dorsal is in relation to the body and posterior can be ambiguous
78
White matter columns in SC
-House ascending and descending tracts
-i.e. info up to and down from brain and brain stem
-The axons of passage to and from the brain
79
Dorsal Columns
-White Matter column
-Major sensory tract going up towards brain
80
Lateral Columns
-White Matter column
-Involved with transmission of motor information down from the brain
81
Ventral Columns
-White Matter column
-Involved with transmission of motor information down from the brain
82
Dorsal Horn
-Grey Matter region
-Sensory information comes in the SC through here
-How sensory information in the periphery comes into the SC
-Recieves sensory input from dorsal roots
83
What is located in Grey Matter in the SC?
-A collection of cell bodies and dendrites
-interneurons
-less myelinated things
-lots of cell bodies and dendrites
-where synapses are happening
84
Ventral Horn
-Grey Matter region
-Transmits commands out to muscles to force muscles to contract
-Houses cell bodies of somatic motor neurons
85
Lateral Horn
-Grey Matter region
-Output cells of SC that serve the ANS
-Houses cell bodies of sympathetic ANS neurons
86
Where do we see distinguishable lateral horns?
In thoracic segments of the SC, because the thoracic segments house the SNS
87
Afferent information
Sensory information coming INTO Spinal Cord
88
Efferent Information
Motor information LEAVING Spinal Cord
89
Afferent and Efferent terms are only used in which system?
Into and Out of Nervous System; NOT WITHIN NS, because there are complicated things happening within the NS
90
Spinal Cord in Cross Section: Cervical Region
-Where we have the most white matter
-All ascending and descending information needs to pass through Cervical segment 1
-Information fans out as it goes
-You lose information of white matter as information reaches its target
91
Where is the smallest region of the cord?
Sacral level, S3
-Smallest amount of white matter
-We are at the far end of the cord
-We don't have lots of information needing to be transmitted at this point
92
As we move up the spinal cord, what happens with white and grey matter?
-Information comes in from sensory systems and we layer more information up as we get closer to cephalic region
-Everything from sacral needs to get the the brain
93
How does the butterfly shape of grey matter change throughout the cord?
-We have BIG ventral horns of grey matter in Cervical region (because of arms and arm muscle quantity)
-We have smaller ventral horns in Thoracic region because less somatic things
-We have DISTINCT Lateral Horns in Thoracic region (internal organs through controlling ANS)
-Less white matter in Lumbar Region and LOTS of grey matter/ BIG ventral horns because of leg muscles to control
94
Dorsal Root
Sensory Information coming INTO cord
95
Ventral Root
Motor information going OUT of cord
96
Where do the Dorsal and Ventral Root meet?
Dorsal root ganglion
-sensory and motor information are being transmitted within the same bundle of tissue (nerve)
97
Dorsal Root Ganglion
-Specialized structure outside of the CNS
-Swollen section just as the nerve is being formed
-Houses the cell bodies for different afferent fibres
98
Prolapsed Disc
Nerves pass through two vertebrae and vertebrae are separated by a disc to act as a cushion to have a mobile spine.
-If it breaks down over time and a bulge in the disc pushes out towards spinous processes, it can crush the spinal nerve as it exits the vertebral column
99
A prolapsed disc can cause...
Neural damage to our spinal nerves (pinching on spinal nerve)
100
Osteoarthritis
Inflammation that impinges on the function of spinal nerves as they pass through the vertebral column
101
Spinal nerves ___ at ____ and ___ material to form ___ nerves
Merge, Plexuses, Swap, Peripheral
102
When a spinal nerve exits a vertebral column...
It isn't yet a peripheral nerve (but still part of PNS)
Information within clusters of the spinal nerves merge and fuse/trade axons to develop our peripheral nerves and produce functions and behaviours of that nerve
103
Lumbosacral Plexus
Legs have more responsibility given their size and importance
104
Why is differentiating between spinal and peripheral nerves important?
Distinction for injuries
105
Peripheral nerve territories represent ______ dermatome
More than one.
Peripheral nerves are made up of multiple dermatomes
106
A loss of dermatome indicates what?
CNS injury
107
Loss of peripheral nerve territory indicates?
Peripheral nerve injury
108
Main blood supply to the brain
Carotid arteries
-In the front
109
What arteries come up the back through vertebrae?
Vertebral arteries
110
Communicating Arteries
-Come off carotid arteries
-Make connections so we have a continuous blood supply loop
111
Circle of Willis
-Unique to the brain
-Preserves blood supply to the brain should one side have a loss of blood supply
-Provides redundancy to the system
-A neurosensory protective mechanism
-May not provide activity
112
What nerves come off of Internal Carotid Artery
Anterior Cerebral a.
Middle Cerebral a.
Posterior Cerebral a.
113
Anterior Cerebral Artery
Serves portion of cerebral cortex largely to front of the brain
114
Middle Cerebral Artery (MCA)
-Largest artery coming off carotid
-Largest blood vessel serving the brain
-A continuation of the carotid a. functionally
-Most involved with stroke
115
Posterior Cerebral Artery
Serves cortical regions to the back of the brain
116
Basilar artery
-Single blood vessel supplying all tissue of the brainstem and continues into the circle of willis
-Another source of blood into the circle of willis
117
From lateral view, the MCA serves a large territory of...
The cerebral cortex
117
Functions impacted by PCA impairment
-visual impairments (because in occipital lobe)
-motor discoordination, ataxia, etc
118
Functions impacted by MCA impairment
Motor and sensory cortices
Hearing
Smaller branches are usually blocked so knowing anatomy helps understand where the infarct is located and therefore understand symptomology
119
Motor and Sensory Homunculus anatomical distribution
Typically very similar
120
MCA serves what region?
Hand, arm, face, motor cortex
121
ACA serves what region?
Lower body, torso
