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Flashcards in Pathology if the CNS Deck (120)
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1

what two conditions can cause a significant loss of function to the CNS

- ischemia
- infection

2

why may a small injury from ischemia or infection to one cell cause loss of function to the whole CNS

because the cells in the CNS are connected

3

list the order of cells of the CNS which are susceptible to injury from most to least

- neurons
- oligodendrocytes
- astrocytes

4

what are the roles of astrocytes in the CNS

they maintain the homeostasis of ion channels and ions of the CNS and regulating ionic composition & neurotransmitters

5

how do astrocytes work in order to maintain homeostasis of components within the CNS

by picking up metabolites released in the CNS & picking up GABA & glutamate

6

what is the role of microglia in the CNS

act as macrophages in the CNS by removing infectious elements within the CNS

7

what is the role of oligodendrocytes in the CNS

involved in myelination around the nuclei

8

list the things which causes actions of neurons to injury in the CNS

- acute neural injury - 'red neurons'
- sub-acute and chronic - 'degenerations'
- ageing - inclusion bodies, lipofuscin
- neurodegeneration - alzheimer's (neurofibrillary tangles)

9

what is acute damage in the CNS neurons caused by

ischemia

10

which areas of the brain tend to get infarcts and ischemia

areas between the main arteries e.g. the anterior cerbral artery - ACA & MCA or between the MCA & PCA
or
in the deeper structures e.g. basal ganglia & thalamus

11

why are the deeper structures such a basal ganglia & thalamus at risk to ischemia and stroke

as there is not any collateral supply to the deeper structures as around the brain you have the meninges surrounding it

12

what is the ACA, MCA & PCA areas known as

the watershed areas

13

what do the neurons appear as following an infarct with H and E staining

damaged cells are stained red (ischemic neurons under stress)

14

what do the neurons undergo following an infarct

necrosis & macrophages/microglia scavenge debris

15

which structure of the CNS is not as susceptible to ischemia compared to neurons

oligodendrocytes

16

what is the appearance of the nuclei of oligodendrocytes

small & round

17

what is the name of a tumour of the oligodendrocytes

oligodendoglioma

18

what happens as a result of a oligodendoglioma (tumour)

proliferation/increase in the number of oligodendrocytes compared to that of normal tissues

19

what is it called when there is an increase of the number of cells following a oligodendoglioma

hyperplasia

20

what is multiple sclerosis (MS)

a demyelinating disease (myelin loss - oligodendrocytes)

21

over which structure do oligodendrocytes have darker rounder nuclei

astrocytes (in H and E staining)

22

what are astrocytes

metabolic buffers and detoxifiers in the brain

23

what do astrocytes have a similar function to

fibroblasts (healing)

24

what do astrocytes form

part of the blood brain barrier
forms a protective structure within the choriocapillaris

25

why do astrocytes form part of the blood brain barrier

to protect the CNS from drugs (which is why it can be very hard to reach the brain)

26

why is it not useful to carry out chemotherapy if someone has a brain tumour, and what is a more effective alternative

astrocytes prevents the job of chemotherapy drugs to reach the CNS in the brain, brain surgery is more effective at removing the tumour

27

what is gliosis

the hypertrophy and hyperplasia of astrocytes in response to stress

28

what do you get an increase of in astrocyte hyperplasia

gliosis

29

what is the increase in astrocyte as response from

ischemic GFAP (glial fibrillary acidic protein)

30

what happens to the microglia in response to injury

proliferates, aggregates around foci of necrosis (as any other macrophage would, i.e. moves to the site of damage to initiate wound healing & repair), phagocytose apoptotic/necrotic neurons