Cerebrovascular Disease Flashcards Preview

Neurology > Cerebrovascular Disease > Flashcards

Flashcards in Cerebrovascular Disease Deck (68)
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1

what are bridging veins

perforate through the arachnoid and dura, very delicate and can rupture in trauma

2

what are the types of glial cells and their functions

astrocytes- supporting structures in brain
oligodendrocytes- myelination
ependymal cells - ciliated cuboidal/ columnar epithelium that lines the ventricles
microglia- immune monitoring and antigen presentation

3

what can damage to nerve cells lead to

rapid necrosis with sudden acute functional failure
slow atrophy with gradually increasing dysfunction

4

what is nissl substance

material consisting of granular endoplasmic reticulum and ribosomes that occurs in nerve cell bodies and dendrites

5

what is acute neuronal injury/ red neurone

occurs due to hypoxia/ ischaemia
results in neuronal cell death
-shrinking and angluation of nuclei
-loss of the nucleolus
-intensely red cytoplasm

6

what are the axonal responses to nerve injury

increased protein synthesis (cell body swells, enlarged nucleus)
chromatolysis (margination and loss of nissl substance)
degeneration of axon and myelin sheath distal to injury (wallerian degeneration)

7

what happens in neuronal atrophy (chronic degeneration)

shrunken, angulated and lost neurones, small dark nuclei, accumulation of lipofuscin pigment, reactive gliosis

8

what are sub cellular alterations (inclusions) cell damage

happen in neurodegenerative conditions
inclusions accumulate with ageing/ in viral infections

9

what type of damage are oligodendrocytes sensitive

oxidative damage

10

what cell type is damage in demyelinating disorders

oligodendrocyte

11

what does damage to the myelin sheath cause

reduced conduction and exposition of the axon

12

what do astrocytic processes do

envelop synaptic plates
wrap around vessels and capillaries within the brain (how they control BBB and cerebral blood flow)

13

what is the role of astrocytes

ionic, metabolic and nutritional homeostasis (do anaerobic glycolysis and give lactate to neurones. also moderate glutamate production)
work in conjunction with endothelium to maintain BBB
repair and scar formation (as no fibroblasts to do this)

14

what is gliosis

an astrocytic response that indicated CNS damage
astrocyte hyperplasia and hypertrophy
nucleus enlarges, becomes vesicular, nucleolus is prominent
cytoplasmic expansion

old lesions (equivalent to scarring)- meshwork of glial fibrils

15

what do ependymal cells provide a pathway for

ascending infection (line ventricles)

16

what are the possible causes of nervous system injury

Hypoxia
Trauma
Toxic insult (exogenous and endogenous due to metabolic sustances within brain)
Metabolic abnormalities
Nutritional deficiencies
Infections
Genetic abnormalities
Ageing

17

what can cause CNS hypoxia

cerebral ischaemia, infarct, haemorrhage, trauma, cardiac arrest, cerebral palsy

18

how much of total body resting oxygen does the brain consume

20%

19

how much can cerebral blood flow increase to maintain oxygen consumptoms

only two fold

20

what happens after onset of ischaemia in the brain

mitochondria inhibit ATP synthesis
ATP reserves consumed within a few minutes

21

what is excitotoxicity

In context of energy failure- neuronal depolarisation causing glutamate release
At same time re uptake of glutamate by astrocytes is inhibited due to energy failure causing accumulation in synaptic space creating a glutamate store which leads to excitation of the post synaptic glutamate receptors= rapid accumulation of Ca in post synaptic neurone what causes;
protease activation
mictochondrial dysfunction
oxidative stress

these things are the main mediators of injury

22

what are the types of oedema

cytotoxic (pre morbid process, accumulation of Na and Cl in neurones moves water from interstitium into cell)

ionic (water goes into interstitium because of deficiency caused by cytoxic oedema)

vasogenic (large molecules like albumin enter interstitium from vessels (more marked swelling that ionic)

haemorragic (blood cells cross BBB if vessel damage bad enough)

23

what helps to maintain blood brain flow

autoregulatory mechanisms
dilatation and constriction of cerebral vessels

24

what is the definition of cerebrovascular disease

any abnormality of brain caused by a pathological process of blood vessels

25

what are the main manifestations of cerebrovascular disease

brain ischaemia and infarction
haemorrhages
vascular malformations
aneurysms

26

what is global hypoxic ischaemic damage

generalised reduction in blood flow/ oxygenation
causes:
-cardiac arrest
-severe hypotension (hypovolaemic shock)
-trauma

27

what is focal cerebral ischaemia and infarction

where the is restriction of blood flow to a localised area of the brain
e.g. a vascular obstruction

28

what are the watershed areas

zone between two arterial territories
particular sensitive to loss of BP

29

what cell type is most sensitive to hypoxia in brain

neurones, especially in neocortex and hippocampus

30

a blood pressure below what leads to hypoperfusion in the brain

50 mmhg