Cerebrovascular Disease

Question 1

List 3 types of glial cells in CNS, glial cells come from ectoderm

Answer 1

Astrocytes,
Oligodendrocytes,
Ependymal cells

Question 2

List 3 types of cells of CNS and 3 supporting structures

Answer 2

Neurons, glial cells, microglia

& connective tissue, meninges and blood vessels

Question 3

Microglia is the ____ of the CNS

Answer 3

Macrophage

Question 4

What is nissl substance and where is it

Answer 4

Is in cell body, has granular appearance and consists of endoplasmic reticulum and ribosomes

Question 5

What is Red Neuron?

Answer 5

Pathological hallmark of severe acute neuron injury, usually in context of hypoxia/ischaemia

Question 6

Red Neuron changes seen within how many hours after irreversible insult to cell?

Answer 6

12-24hrs

Question 7

Red neuron pattern changes?

Answer 7

Shrinking and angulation of nuclei,
Loss of nucleolus,
Intensely red cytoplasm

Question 8

Axonal injury reaction (3)

Answer 8

Cell body swelling and enlarged nucleolus due to increased protein synthesis,
Chromatolysis - disolving of Nissl granules,
Degeneration of axon and myelin sheath distal to injury

Question 9

Simple neuronal atrophy - chronic degeneration, morphology and which cells does it occur in?

Answer 9

Shrunken, angulated neurones,
 lost neurons, 
small dark nuclei, 
lipofuscin pigment, 
reactive gliosis
Happens to functionally related groups of neurones.

Question 10

3 instances where inclusions appear in brain?

Answer 10

Common in neurodegenerative conditions,
Accumulate with ageing,
In viral infections affecting the brain

Question 11

What inclusions do you get in Alzheimer’s disease?

Answer 11

Neurofibrillary tangles

Question 12

What are inclusion bodies in neurons?

Answer 12

Aggregates of protein

Question 13

Oligodendrocytes have relatively limited reaction to injury but are sensitive to what type of damage?

Answer 13

Oxidate damage

Question 14

Damage to the myelin sheath can lead to? (2)

Answer 14

Conduction reduced & axons exposed to injury

Question 15

List two structures the astrocytic processes envelop?

Answer 15

Envelop synaptic plates,

Wrap around vessels and capillaries within the brain

Question 16

What are the 3 main roles of astrocytes?

Answer 16

Ionic, metabolic and nutritional homestasis,
Help maintain BB barrier,
Main cell for repair and scar formation (cos no fibroblasts)

Question 17

Astrocytic response is the most import histopathological indicator of CNS injury. What is the name of the astrocytic response to CNS injury?

Answer 17

Gliosis

Question 18

Describe early gliosis histopathologically

Answer 18

Astrocyte hyperplasia and hypertrophy,
nucleus enlarges, becomes vesicular,
the nucleolus becomesprominent,
Cytoplasmic expansion with extension of processes

Question 19

Describe old lesions of gliosis

Answer 19

Are translucent and nuclei become small & dark & lie in glial fibrils which are dense network of processes

Question 20

Ependymal cells line what in the brain?

Answer 20

Ventricular system

Question 21

Ependymal cells have a limited reaction to injury. True/false?

Answer 21

True

Question 22

Ependymal cells can cause problems in what 2 ways?

Answer 22

Can undergo tumour transformation and block CSF production,

Can be involved in infection as infection spreads through CSF

Question 23

Injured ependymal cells scar in what way?

Answer 23

Local proliferation of sub-ependymal astrocytes into ependymal granulations

Question 24

How do microglia respond to injury?

Answer 24

Proliferate and form aggregates around areas of necrotic and damaged tissues

Question 25

What is the difference between M1 and M2 microglia?

Answer 25

M1 are pro-inflammatory and more chronic,

M2 are anti-inflammatory, phagocytic and more acute

Question 26

List 8 causes of nervous system injury

Answer 26

Hypoxia, 
Trauma, 
Toxic insult, 
Metabolic abnormalities, 
Nutritional deficiencies, 
Infections, 
Genetic abnormalities, 
Ageing

Question 27

Brain consumes approximately what percentage of total body resting O2 consumption?

Answer 27

Approx. 20%

Question 28

What enzyme is thought to consume 70% of the brains energy?

Answer 28

Na+/K+ channel ATPase

Question 29

Cerebral blood flow can only increase by how much to maintain oxygen delivery?

Answer 29

Can only double

Question 30

After onset of ischaemia, what happens in terms of ATP?

Answer 30

Mitochondrial inhibition of ATP synthesis leads to ATP reserves being consumed within few minutes

Question 31

Excitotoxicity occurs in neurons in the case of energy failure which can occur in hypoxia, trauma and some neurodegenerative conditions. Outline what occurs in excitotoxicity.

Answer 31

Hypoxia and hypogylcaemia

• > neuronal depolarisation so glutamate released + inhibition of astrocytes reuptake of glutamate
• > glutamate storm and excitation
• > increased Ca+ going into post-synaptic membrane
• > protease activation + mitochondrial dysfunction + oxidative stress
• > apoptosis

Question 32

Oedema also mediates injury in CNS. 4 main types?

Answer 32

Cytotoxic oedema
Ionic oedema,
Vasogenic oedema,
Haemorrhagic conversion

Question 33

Cytotoxic oedema occurs how and is this swelling?

Answer 33

Extracellular ions e.g. sodium and chloride move into cells and bringing in water by osmosis - no swelling occurs because there is no outside fluid coming in its just moving from one area to another within a confined space

Question 34

Ionic oedema is the first dysfunction of the BB barrier. How does cytotoxic oedema lead to ionic oedema?

Answer 34

Cytotoxic oedema means lack of sodium in extracellular space and so sodium ions cross BB barrier and this drives chloride ions across too, this creates osmotic gradient for water to move in.

Question 35

How does vasogenic oedema happen?

Answer 35

Breakdown of BBB due to disruption of endothelial tight junctions which leads to plasma proteins e.g. albumin crossing into extracellular space which are very osmostically active so water in too!

Question 36

In both ionic and vasogenic oedema substances move across the blood brain barrier. However in which type of oedema does the BB barrier still maintain its integrity?

Answer 36

Ionic

Question 37

In vasogenic oedema the BBB is still intact enough for RBCs to not pass through. What is it called when BBB is very dysfunctional and RBCs begin to pass through BBB? This happens in 30-40% of what?

Answer 37

Haemorrhagic conversion, happens in 30-40% of ischaemic strokes