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
