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Flashcards in Pathology Deck (71)
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1

What are the cellular components of the CNS?

Neurones
Glial cells: astrocytes, oligodendrocytes, ependymal cells
Microglia
Supporting structures: connective tissue, meninges, blood vessels

2

What are the 2 ways that neurones will respond to injury?

Rapid necrosis with sudden acute functional failure
Slow atrophy with gradually increasing dysfunction - seen in age related cerebral atrophy

3

When will you see a red neurone?

Context of hypoxia/ ischaemia
Visible 12-24 hours after an irreversible insult to the cell
Results in neuronal cell death

4

What is the pattern to acute neuronal injury?

Shrinking and angulation of nuclei
Loss of nucleolus
Intensely red cytoplasm

5

How will axons respond to injury?

Increased protein synthesis; cell body swelling and enlarged nucleolus
Chromatolysis; margination and loss of nissl granules
Degeneration of axon and myelin sheath distal to the injury - wallerian degeneration

6

What is simple neuronal atrophy?

Shrunken, angulated and lost neurones
Small dark nuclei
Lipofuscin pigment
Reactive gliosis

7

What is gliosis?

Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system
Hypertrophy and hyperplasia of astrocytes

8

What are sub-cellular alterations (inclusions)?

Common in neurodegenerative conditions such as neurofibrillary tangles in alzheimer's
Inclusions appear to accumulate with ageing
Will get inclusions in viral infections

9

What is the function of an oligodendrocyte?

Wraps around axons to form a myelin sheath to facilitate salutatory conduction

10

What will occur with damage to an oligodendrocyte?

Variable pattern of demyelination
Apoptosis

11

Are oligodendrocytes sensitive to oxidative damage?

Yes

12

What is an astrocyte?

Star shaped cell with multipolar cytoplasmic processes

13

Where can strocytes be found?

Present throughout the CNS
Astrocytic process; envelops synaptic plates
Wraps around vessesl and capillaries within the brain

14

What are the roles of astrocytes?

Ionic, metabolic and nutritional homeostasis
Work in conjunction with endothelial cells to maintain the BBB
Main cell involved in repair and scar formation - gliosis

15

Where can you find ependymal cells?

Ventricular system

16

What occurs with disruption to these cells?

Local proliferation of sub-ependymal astrocytes to produce small irregularities on the ventricular surfaces termed ependymal granulations

17

What is the microglia response to injury?

Proliferation
Recruited through inflammatory mediators; forms aggregates around areas of necrotic and damaged tissues

18

What is the difference between M1 and M2 microglia?

M2; anti-inflammatory, phagocytic, more acute
M1; pro-inflammatory, more chronic

19

What are causes of nervous system injury?

Hypoxia
Trauma
Toxic insult - exogenous and metabolic disruption within brain releasing noxious substances
Metabolic abnormalities
Nutritional deficiencies
Infections
Genetic abnormalities
Ageing

20

What can result in hypoxia?

Cerebral ischaemia
Infarct
Haemorrhage
Trauma
Cardiac arrest
Cerebral palsy

21

What occurs in the brain cells after the onset of ischaemia?

Mitochondrial inhibition of ATP synthesis leading to ATP reserves being consumed within a few minutes - underlies rapid loss of consciousness in hypoxia

22

What occurs in terms of glutamate in excitotoxicity?

Glutamate released by depolarising neurone
Uptake of glutamate inhibited at astrocytes
Glutamate storm and excitation
Increased calcium resulting in protease activation, mitochondrial dysfunction and oxidative stress

23

What results in cytotoxic oedema?

Intoxication
Reye's
Severe hypothermia

24

What results in ionic oedema?

Hyponatraemia
Excess water intake; SIADH

25

What results in vasogenic oedema?

Trauma
Tumours
Inflammation
Infection
Hypertensive encephalopathy

26

Which areas of the brain does the anterior cerebral artery supply?

Midline portions of the frontal lobes and superior medial parietal lobes.

27

Which areas of the brain does the middle cerebral artery supply?

Portion of the frontal lobe and the lateral surface of the temporal and parietal lobes, including the primary motor and sensory areas of the face, throat, hand and arm, and in the dominant hemisphere, the areas for speech

28

Which areas of the brain does the posterior cerebral artery supply?

Occipital cortex

29

What is global hypoxic ischaemia?

Generalised reduction in blood flow/ oxygenation

30

What can cause global hypoxic ischaemic damage?

Cardiac arrest
Severe hypotension; trauma with hypovolaemic shock