Pathology

Question 1

What is acute neuronal injury?

Answer 1

occurs due to hypoxia/ishcaemia

results in neuronal cell death

Question 2

What is the pathology of neuronal injury?

Answer 2

shrinking and angulation of the nuclei
loss of the nucleus
intensely red cytoplasm

Question 3

When is acute neuronal injury present?

Answer 3

12-24hours after an irreversible insult to the cell

Question 4

What are the different axonal reactions to injury/disease?

Answer 4

increased protein synthesis - cell body swelling and enlarged nucleus
chromotolysis - margination and loss of nissi granules
degeneration of axon and myeline sheath distal to injury

Question 5

What is the role of oligodendrocytes in the CNS?

Answer 5

wrap around axons forming a myelin sheath

they are very sensitive to oxidative stress (hypoxia)

Question 6

What is the role of astrocytes in the CNS?

Answer 6

work with endothelial cells to maintain the BBB

wrap around vessels and capillaries in the brain

Question 7

What is gliosis?

Answer 7

nonspecific reactive change of glial cells in response to damage to the CNS
involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, microglia, and oligodendrocytes

Question 8

What does gliosis lead to?

Answer 8

scarring - nuclei become small and dark and lie in a dense net of processes

Question 9

What pathology is seen in gliosis?

Answer 9

astrocyte hyperplasia and hypertrophy
nucleus enlarges - becomes vesicular
cytoplasmic expansion

Question 10

What is the role of ependymal cells?

Answer 10

lines the ventricular system

distruption of ependymal cells causes local proliferation of sub ependymal astrocytes

Question 11

What is the role of microglia cells?

Answer 11

form aggregates around necrotic and damaged tissue
two types:
M1 - pro inflammatory, more chronic
M2 - antinflammatory, phagocytic, more acute

Question 12

How does hypoxia cause nervous system injury?

Answer 12

brain consumes 20% of total body oxygen
when there is ischeamia - the mitochondrial inhibition of ATP synthesis leads to ATP reserves being consumed within minutes - this causes excitotoxicity

Question 13

What is excitotoxicity?

Answer 13

large accumulation of glutamate in the synaptic space which causes excitation of the Ca in the post synaptic neuron which leads to oxidative stress, mitochondrial dysfunction and protease activation

Question 14

When would ionic oedema occur?

Answer 14

hyponatreamia

excess water intake

Question 15

When would cytotoxic oedema occur?

Answer 15

due to intoxication

severe hypothermia

Question 16

When would vasogenic oedema occur?

Answer 16

trauma
tumours
inflammation
infection 
hypertensive encephalopathy

Question 17

What is hypertensive encephalopathy?

Answer 17

global cerebral oedema
tentorial and tonsillar herniation
arteriolar fibrinoid necrosis
petechiae