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Andrea > 30/09/20 > Flashcards

30/09/20 Flashcards

1
Q

Which are more abundant? Neurons or glial cells?

A

Glial cells are 5x more abundant than neurons

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2
Q

What are the glial cell types in the CNS and what do they do?

A

Oligodendrocytes myelinate axons in CNS and provide overall structural framework to it.​

Astrocytes are important for blood-brain barrier.​

Microglia remove waste, pathogens, debris by phagocytosis.​

Ependymal cells line ventricles of brain and central canal of spinal cord – produce CSF.

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3
Q

What are the glial cells in the PNS and what do they do?

A

Satellite cells maintain nutrient and neurotransmitter levels around cells.​
Schwann cells myelinate axons in PNS.

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4
Q

When does the cranial neuropore close?

A

Day 25

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5
Q

When does the caudal neuropore close?

A

Day 27

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6
Q

What are the three primary brain vesicles and when do they form?

A

Week 4

Prosencephalon
Mesencephalon
Rhombencephalon

(Pro Me at Rhombus)

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7
Q

What are the secondary brain vesicles and when do they form?

A

Week 6

Telencephalon
Diencephalon

Mesencephalon

Metencephalon
Myelencephalon

(Telephone Diana, Me Met Myelen)

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8
Q

What structures do the secondary brain vesicles form?

A

Telencephalon –> Cerebral hemispheres
Diencephalon –> Thalamus/Hypothalamus

Mesencephalon –> Midbrain

Metencephalon –> Cerebellum and pons
Myelencephalon –> Medulla

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9
Q

What is the calcarine sulcus?

A

In occipital lobe, associated with primary visual cortex.

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10
Q

What does the cingulate gyrus do?

A

Cingulate gyrus controls heart rate, resp rate, pain processing and bladder control.

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11
Q

What is the brodmann areas of the somatosensory cortex?

A

1

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12
Q

What is the Brodmann area of the primary motor cortex?

A

4

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13
Q

What is the Brodmann area of the pre-motor cortex?

A

6

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14
Q

What is synaesthesia?

A

Synaesthesia refers to a combination of senses that provides an unusual interpretation​

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15
Q

What do association fibres connect?

A

Association fibres (within a hemisphere)​

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16
Q

What do commissural fibres connect?

A

​Commisural fibres (between hemispheres)

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17
Q

What do projection fibres connect?

A

Projection fibres (to brainstem/spinal cord)​

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18
Q

What does the tentorium cerebelli do?

A

Prevents occipital lobe compressing the cerebellum especially during neck/head flexion & extension

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19
Q

What is a Jefferson fracture?

A

C1 (Atlas) shattered

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20
Q

Where is a Dens fracture and how can this occur?

A 
C2 (Axis)
Dens fracture (#) can occur via rapid flexion-extension of the neck e.g. rapid deceleration in a motor vehicle collision​
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21
Q

What is a hangman fracture?

A

Neural arch is broken off from the body of the vertebrae (C2?).
Weight of cranium moves C1 and C2 anteriorly, causing kink in spinal cord. ​

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22
Q

What is vertebrae promininens and where is it found?

A

Vertebrae prominens​
The first prominent spinous process​
C7

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23
Q

What are the differences between the vertebral bodies as you go down the vertebral column?

A

Cervical vertebrae have bifid process and foramen transversarium

Thoracic vertebrae have heart-shaped body

Lumbar vertebrae have kidney-shaped body and short and square spinous process body

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24
Q

What could you use the C7 transverse process (vertebrae prominens) for?

A

Lung apex

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25
Q

What are the zygapophyseal joints?

A

Located between articular facets of adjacent vertebrae​
​
​Simple synovial plane joints​
​
Facets change orientation from superior-to-inferior​
​
​Joints can dislocate leading to vertebral body displacement – can compress vertebral canal​

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26
Q

What is spondylolysis?

A

Fracture in the region of the articular facets without displacement
Scotty dog with collar

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27
Q

What is spondylolisthesis?

A

Lumbar vertebrae body slips or moves anteriorly. Can be due to a traumatic, degenerative or dysplastic cause. Often accompanies spondylolysis.

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28
Q

In hyperkinetic disorders, is there reduced or increased activity of GPi?

A

Reduced

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29
Q

In hypokinetic disorders, is there reduced or increased activity of GPi?

A

Increased

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30
Q

What will you get with a cerebellar hemisphere lesion?

A

Ipsilateral problems with limbs (Appendicular ataxia),

dysdiadochokinesia, dysmetria

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31
Q

What will you get with a vermil lesion?

A

Truncal ataxia

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32
Q

What will you get with a floculo-nodular lesion?

A

Dizziness

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33
Q

What do Meissner corpuscles detect?

A

Discriminative touch

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34
Q

What do pacinian corpuscles detect?

A

Deep pressure and vibration

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35
Q

What do Ruffini endings detect?

A

Touch

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36
Q

What do Merkel discs detect?

A

Light touch

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37
Q

What do free nerve endings detect?

A

Pain and temperature

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38
Q

In the dorsal column pathway from the face, what tract do the second order neurons travel in?

A

Trigeminal lemniscus to VPM of thalamus

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39
Q

What can happen with dorsal column damage at the spinal cord? What can cause this?

A

Can be caused by tertiary syphilis (demyelination of dorsal column), compression, infarction, infection or B12 deficiency.

Symptoms will be ipsilateral following spinal cord damage.
Pseudoathetosis
Sensory ataxia leading to positive Romberg sign and stamping gait

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40
Q

What will syringomyelia affect?

A

Affect DECUSSATING neurons in the STT

You get that cape like sensory loss

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41
Q

What is the significance of Clarke’s Dorsal Nucleus?

A

Lower limb muscle spindle info enters cord and synapses in Clarke’s Dorsal Nucleus, then ascends in the DSCT​
(Sits between ~C8-L3)

Clarke’s Nucleus is one of the areas affected in Freidrich’s ataxia

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42
Q

What would damage to the spinocerebellar tract look like?

A

Symptoms normally masked by other motor weakness/paralysis​
​
Pure lesions could cause: ​
​
- Ataxia / malcoordination of motor action​
​
- Wide-based gait

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43
Q

What is a motor unit?

A

Motor unit = a lower motor neuron & the extrafusal muscle fibres it innervates​

Powerful muscles have lots of muscle fibres per motor unit. Fine control has fewer muscle fibres per motor unit.

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44
Q

In the motor homunculus, what is found inside the longitudinal fissure?

A

legs

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45
Q

What do alpha motor neurons innervate?

A

a motor neurons innervate MOTOR UNITS of Extrafusal fibres

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46
Q

What do gamma motor neurons innervate?

A

g motor neurons innervate Intrafusal fibres of MUSCLE SPINDLES

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47
Q

What degeneration is seen in ALS?

A

Degeneration of the corticospinal tracts and ventral horn of the spinal cord​
UMN and LMN symptoms are seen together​
Often limb onset first –> then spreading to other areas of body

Fasciculations​
Spasticity/Cramps​
Weakness (limbs, neck, diaphragm)​
Dysarthria, dysphagia, dyspnoea

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48
Q

Where do ventral CST UMNs decussate?

A

Only at the level where it exits the spinal cord.

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49
Q

What symptoms would you get with a CST lesion?

A

Corticospinal tract lesions (primarily LATERAL Tract - since it carries most the fibres) ​
can be associated with loss of fine-skilled voluntary movements and other signs ​
​
​1) Abdominal reflexes
2) Cremasteric reflex
3) Ankle clonus
4) Babinski sign

Clonus = rhythmic series of contractions (oscillations) caused by the alternate stretching & unloading of muscle spindles in a patient with spastic muscles

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50
Q

What does the lateral vestibulospinal tract do?

A

Increases EXTENSOR muscle tone (anti-gravity muscles, keep you upright!)​

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51
Q

Where do reticulospinal tracts originate from?

A

Originate from nuclei in the pons/medulla

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52
Q

Why can patients smile, even if they have bilateral corticobulbar lesions to CN VII?

A

Reticulospinal tract is still in tact and controls emotional movement of muscles of facial expression

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53
Q

What are the 2 parts of the Reticulospinal tract?

A

the Medullary and Pontine Tracts

The Medullary Tract and Nucleus helps to control the Sympathetic Chain

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54
Q

Describe the stages in the myotatic reflex

A

1) A passive muscle stretch is sensed by muscle spindle​
2) Reflex arc stimulates a contraction of the stretched muscle​
3) Reflex arc inhibits antagonist muscle from contracting (relaxes the opposing muscle)

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55
Q

Describe the flexor reflex

A

Quick withdrawal of a limb from a painful (noxious) stimuli

Mediated by free nerve endings​
​
Synaptic connections span several spinal cord levels​
​
Stimulates ipsilateral flexors of limb​
​
Inhibits ipsilateral extensors of limb
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56
Q

Describe the crossed extensor reflex

A

Activation of the flexor reflex in a weight-bearing limb

Ipsilateral flexor withdrawal​
​
Contralateral extensor activation

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57
Q

On T2 MRI, what appears black and what appears white?

A
  • Bone appears as black​

- CSF appears white​

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58
Q

What parts of the brain does the pupillary light reflex test?

A

​Tests functioning of the retina, CN II, Midbrain and CN III

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59
Q

How does glaucoma affect the visual fields?

A

Reduces the visual fields

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60
Q

How does retinitis pigmentosa affect the visual fields?

A

Causes tunnel vision

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61
Q

What does papilloedema look like?

A

Raised disc, engorged veins

62
Q

What does oculomotor nerve innervate?

A

4/6 extraocular eyeball muscles, levator palpebrae superioris (eyelid muscle), sphincter pupillae (lens accommodation), and ciliary muscle of the eye (to constrict pupil)​

63
Q

What would happen with a CN III lesion?

A 
Complete Ptosis on affected side
​
Eye is ‘Down & Out’: Exotropia ​
unopposed LR (CN VI) / SO (CN IV)​
​
Dilated, Non-Reactive Pupil​
Consensual light reflex intact in unaffected eye​
​
Diplopia: Double vision (horizontal & vertical)
64
Q

What is special about CN IV?

A

CN IV is the ONLY cranial nerve to emerge from the dorsal side of the brainstem, and the ONLY cranial nerve to decussate before it even emerges from the brainstem!

65
Q

What would happen with a CN IV lesion?

A

Upward deviation and extorsion (outward rotation of the eye)​
​
Vertical diplopia: worse when looking down (e.g. going down stairs/reading)​

66
Q

What would happen with a CN VI lesion?

A

If lesioned, you will not have lateral movement of the eye​
​
Eye rests in adducted position = convergent squint​
​
Horizontal diplopia​
​
Diplopia worse when looking toward

67
Q

What will damage to CN III, CN IV and CN VI lead to?

A

Lesions can also lead to:​
Diplopia​
Compensatory head movements​
​
​Horizontal diplopia can indicate medial (CN III) or lateral rectus (CN VI) issues​
​
Vertical diplopia can indicate issues with Superior oblique (CN IV) / Inferior oblique or rectus (CN III)

68
Q

Where do CN V fibres exit the brainstem?

A

Lateral pons

69
Q

What innervates the angle of the mandible?

A

cervical nerves, NOT CN Vc

70
Q

What side will the mandible deviate towards in a CN V motor lesion?

A

​Jaw jerk exaggerated in UMN lesions​
​
Open mandible - deviates toward weak side due to opening action of medial pterygoid muscle

71
Q

What nuclei does the facial nerve come from?

A

Facial nucleus & Superior Salivatory nucleus (Pons)

72
Q

What foramen does CN VII pass through?

A

Internal Acoustic Meatus and Stylomastoid foramen

73
Q

What does the Greater Petrosal Nerve supply?

A

Parasympathetic to lacrimal gland and salivary glands

74
Q

What do you get with an UMN lesion (eg. stroke) of CN VII?

A

Forehead sparing

75
Q

What do you get with a LMN lesion (eg. Bell’s palsy) of CN VII?

A

Full ipsilateral palsy

76
Q

How do you test the vestibular portion of CN VIII?

A

Tested if patient complains of episodes of vertigo​
​
Hallpike Manoeuvre​
​
Positive test produces vertigo rotatory nystagmus toward affected side

77
Q

What nuclei does CN IX originate from?

A

Inferior salivatory; nucleus ambiguus; nucleus solitarius (Medulla)

78
Q

What nuclei does CN X originate from?

A

Dorsal motor; nucleus ambiguus; nucleus solitarius (Medulla)

79
Q

What muscles does CN XI innervate?

A

Sternocleidomastoid and trapezius

80
Q

What can lesion of CN XI lead to?

A

SCM weakness can sometimes lead to head turned to weak side at rest​

81
Q

Which side does the tongue deviate to in a CN XII lesion?

A

Deviates towards weak side

82
Q

What is the reticular formation?

A

Reticular formation is a network of neurons responsible for core physiological processes and states of consciousness.

83
Q

Where does CN V exit the brainstem?

A

Pons

84
Q

Where do CN VI, VII and VIII exit the brainstem?

A

Pontomedullary junction

85
Q

Where do CN III and IV exit the brainstem?

A

Midbrain

86
Q

Where do CN IX and X exit the brainstem?

A

Lateral medulla

87
Q

Where does CN XI originate from?

A

C1-C5 spinal cord

88
Q

Where does CN XII exit the brainstem?

A

Ventral medulla

89
Q

Which cranial nerve emerges from the interpeduncular fossa?

A

CN III

90
Q

What does CN VII wrap around and what can it be compressed by?

A

CN VII wraps around CN VI and can be compressed by 4th ventricle tumours

91
Q

Which cranial nerves hitchhike on CN V’s sensory nucleus? And which part of the nucleus?

A

CN VII, IX and X hitchhike on the spinal nuclei

92
Q

What is bulbar palsy?

A

Lower motor neurone lesion affecting CN VII - XII​
​
Paralysis of pharynx, soft palate, larynx, tongue (sometimes the face & mastication)​
​
Dysarthria, dysphonia, drooling, poor swallowing, aspiration​
​
Flaccid paralysis, wasting, fasciculations​
​
Causes = Polio, radiotherapy, CVE

93
Q

What is pseudo-bulbar palsy?

A

Bilateral corticobulbar tract disorder (upper motor neurone lesion)​
​
Presents initially as LMN lesion; LMN and reflex arc remain functional​
​
Bilateral damage is clinically significant ​
​
Similar symptoms to bulbar palsy but can develop spastic paralysis of pharynx & larynx = airway occlusion emergency​
​
Causes = Head injury, CVE, high brainstem tumour…..​

94
Q

Which cranial nerves could a Superior cerebellar artery aneurysm compress?

A

CN III and CN IV

95
Q

Which cranial nerves could a PCA aneurysm compress?

A

CN III and CN IV

96
Q

What would happen with CN IV motor nucleus damage?

A

CN IV nucleus damage leads to contralateral loss of superior oblique function​
​
Diplopia when reading & descending stairs; head tilted toward side of damaged nucleus to compensate​

97
Q

What does the reticular formation in the brainstem do during sleep?

A 
Midbrain raphe nuclei (seretonin)​
​
Cereulean nucleus active in REM sleep​
​
Hypothalamus metabolises CSF seretonin to produce sleep-inducing molecule
98
Q

What does the reticular formation in the brainstem do when you’re awake?

A

Cholinergic neurons adjacent to cerulean excite the cortex via the thalamus​
​
Hypothalamic nucleus (tuberomammillary)​
​
Basal nucleus of Meynert above optic chiasm also active​

99
Q

What are the different TMJ ligaments?

A
  • Capsule
  • Lateral ligament
  • Sphenomandibular ligament
  • Stylomandibular ligament
100
Q

Where is the third ventricle?

A

In the midline between the two thalami

101
Q

Damage to what area of the brain would cause hemi-spatial neglect?

A

Posterior parietal cortex (superior lobule), especially in right-sided damage

102
Q

What is associative visual agnosia?

A

See object but do not recognise/distinguish

103
Q

What is apperceptive visual agnosia?

A

Fail to perceive/see an object

104
Q

What will happen if you have damage to Broca’s area?

A

Expressive aphasia​

Content correct, but slow or missing words. Like trying to speak a language you’ve just started to learn​

105
Q

What will happen if you have damage to Wernicke’s area?

A 
Receptive aphasia (both auditory & reading) 
Content incorrect, but speech fluent. Can speak fluently but it is nonsense but they don’t realise it’s nonsense.​
106
Q

What will happen if you have damage to Angular gyrus?

A

Alexia and agraphia (inability to read or write)​

107
Q

What will happen if you have damage to the primary auditory cortex?

A

Reduction of hearing sensitivity in both ears (mostly contralateral) & loss of stereo perception of sound origin​

108
Q

What is the blood supply to Broca’s and Wernicke’s area?

A

Middle Cerebral Artery

109
Q

What will happen if you have damage to Arcuate Fasciculus?

A

Conductive aphasia - unable to repeat words.

110
Q

What will happen if you have damage to corpus callosum’s commissural fibres?

A

Split-brain symptoms:
Inability to NAME objects held in left hand​
​Inability to READ left half of visual fields

111
Q

What artery supplies the leg section of primary motor cortex and primary somatosensory cortex?

A

Anterior Cerebral Artery

112
Q

What artery supplies the hand and face section of the primary motor cortex and primary somatosensory cortex?

A

Middle Cerebral Artery

113
Q

What arteries supply the basal ganglia section?

A

Striate and choroidal arteries

114
Q

What arteries supply the choroid plexus and thalamus?

A 
Anterior choroidal (from ICA)
Posterior choroidal (from PCA)
115
Q

What else does the anterior choroidal artery supply?

A

Optic tract​
Lateral geniculate body in thalamus (vision)​
Posterior limb of internal capsule​
Parts of limbic system​

116
Q

What forms the Papez circuit?

A

1) Hippocampus
2) Fornix
3) Mamillary bodies
4) Anterior thalamic nuclei
5) Cingulate gyrus

117
Q

Where is the hippocampus found?

A

Inferomedial temporal lobe

118
Q

What happens if you have damage to hippocampus?

A

Anterograde amnesia​
No new memory formation​
Still able to recall long term memories​
Hippocampus is also involved in memories involving spatial/visual tasks + language ​

119
Q

What is the anterior cingulate gyrus involved in?

A 
Autonomic area: ​
Cardiorespiratory & digestion, visceral response to emotion​
​
Bladder control​
​
Emotional modulation of pain​
120
Q

What is the posterior cingulate gyrus involved in?

A

Vocal area controlling appropriate sentence construction​
​
Memory, cognition ​

121
Q

What nuclei are involved in reward?

A

Septal & Accumbens Nuclei​

122
Q

Which part of the brain is involved in recognising the emotional content of faces?

A

Amygdala

123
Q

What can happen if you have bilateral damage of the amygdala?

A

Kluver-Bucy Syndrome​
Docile, lack of fear/anger​
Increased appetite​
Hypersexual​
Excessive exploratory behaviour w/mouth and hands​
Visual agnosia​
Memory disorders (lack of facial recognition)

124
Q

Where do olfactory neurons travel to?

A

Orbital cortex and piriform cortex (part of temporal lobe)

125
Q

What is the region of greatest visual acuity?

A

Fovea centralis (macula)

126
Q

What are the three layers of the eye?

A

Retina (photo-receptive / sensory region)​
Choroid (vascular)​
Sclera (white outer layer)

127
Q

Where is the blind spot?

A

Optic papilla

128
Q

What will central retinal artery occlusion cause?

A

Blindness

129
Q

What are Baum’s loop and Meyer’s loop?

A

Baum’s Loop –> Superior bundle of loop that arches upwards into parietal lobe)

Meyer’s Loop –> Inferior bundle of loop that arches down into temporal lobe​

130
Q

What is central scotoma?

A

Damage JUST your macular vision if you damage your occipital pole (TIP of striate area)

131
Q

What three things make up accommodation?

A
  • Vergeance
  • Pupillary constriction
  • Lens fattening
132
Q

In lens fattening, does the ciliary body contract or relax?

A

The circumferential ciliary body contracts which then relaxes the suspensory ligaments – this allows the lens to recoil, relax, thus allows it to puff up (become fatter)​

133
Q

What is the sensory part of the cochlea?

A

Organ of Corti

134
Q

How does the Organ of Corti allow you to hear?

A

Organ of Corti has sensory hair cells that detect vibrations. Vibrations transmitted from the perilymph to the endolymph through the vestibular membrane.

135
Q

What can cause sensorineural deafness?

A

Drug linked, viral Rubella in utero, or mumps​

136
Q

What can cause loss of stereo-placement of sound?

A

Can indicate a cortical or thalamic issue/pathology​

137
Q

What can cause tinnitus?

A

Occurs in Méniere’s Disease, URTI, or following exposure to loud sounds​
​
Tensor tympani / stapedius myoclonus (contractions) can cause tinnitus​

138
Q

What is the dynamic part of the vestibular system formed from and what does it do?

A

Formed from semi-circular canals & crista​
​
Acts mainly on eye movements via medial-longitudinal fasciculus​

139
Q

What is the static part of the vestibular system formed from and what does it do?

A 
Formed from maculae ​
(utricle & saccule)​
​
Acts via vestibulospinal pathway​
(3rd major descending pathway)​
​
Pick up static changes of position of the head (even when it is still)​
​
Pick up acceleration of your head​
140
Q

What type of acceleration does the utricle detect?

A

Detect horizontal acceleration (e.g. driving)​
​
Active with head in flexion or extension​

141
Q

What type of acceleration does the saccule detect?

A

Detect vertical acceleration (e.g. falling)​
​
Extensor activation in a fall (strong extensor thrust) – ​
as this activates the Vestibulospinal pathway​
​
Active with head held to side

142
Q

Where do the vestibular nuclei sit?

A

Pontomedullary brainstem

143
Q

What are the 3 inputs to balance and how many can we lose?

A
  • Vestibular
  • Visual
  • Proprioception
    We can lose 1 of our inputs…but lose 2, and we become UNSTABLE…lose postural control!​
144
Q

What is Argyll-Robertson (prostitute’s) pupil?

A

There is NO pupillary light reflex BUT the accommodation reflex/response is WORKING. Therefore, doesn’t use posterior part of brainstem, goes directly to EWN. This indicates there’s damage to brainstem​

145
Q

What happens with EWN damage?

A

No direct or consensual reflex on damaged side ​
Pupil dilated and unreactive​
Cause: Vascular/tumour/brainstem

146
Q

What happens with CN III compression?

A

No direct or consensual reflex on damaged side​
Pupil dilated and unreactive ​
CNIII Compression = loss of all CNIII functions​
CNIII Vascular lesion = sparing of pupillary functions​

147
Q

What is the innervation of orbicularis oculi?

A

CN VII

148
Q

What is the innervation of superior tarsal?

A

sympathetic

149
Q

What is Hering’s law?

A

Extraocular muscles normally have equal and simultaneous innervation

150
Q

What causes internuclear opthalmoplegia?

A

Internuclear opthalmoplegia results from lesions of the MLF​

(Cuts the interneuron connections between CNVI and CNIII)​

151
Q

When the head turns to the right, what happens to the eyes?

A

The right lateral semicircular canal is activated by axial head movement/rotation to the right​. Makes both eyes look to the opposite side​ (left).

Andrea (10 decks)

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