Week 3 Flashcards
What are the two leading causes of brain injury?
- cerebrovascular accidents (CVAs)/stroke
- traumatic brain injury
What are some causes of brain damage?
- cerebrovascular accidents/stroke
- traumatic brain injury
- tumours
- anoxia/hypoxia
- infections
- neurotoxins
- neurological diseases
What percentage of body weight does the brain represent?
2%
What percentage of the body’s oxygen is provided to the brain?
25%
How much cardiac output of the body does the brain require?
15%
Which animal can survive for hours without oxygen supply to the brain
turtles
Loss of consciousness occurs within how many seconds of interrupted blood supply to the brian?
10 seconds
What happens after 20 seconds without blood supply to the brain>
electrical activity ceases
What happens without a blood flow to the brain after 2-3 minutes?
Irreversible brain damage occurs.
Arterial supply involves two pairs of vessels, what are these?
- internal carotid arteries
2. vertebral arteries
What are the two main divisions of the internal carotid system?
- middle cerebral artery
2. anterior cerebral artery
What are the two main divisions of the vertebral - basilar system?
- Basilar artery
2. posterior cerebral arterites
What is the circle of willis?
interconnection of all the arteries which supply blood to the brain
What is one benefit of the circle of willis?
- If one artery is blocked, blood can still be supplied to that area.
- If an artery is blocked on one side, if can be transferred over via the communicating artery
The anterior cerebral artery supplies blood to which part of the brain?
medial
frontal
parietal
The middle cerebral artery supplies blood to which part of the brain?
lateral surface of the hemispheres
Posterior cerebral arteries supply blood to which part of the brain?
medial part of the occipital lobe
inferior surface of the temporal lobe
What is CVA? (stroke)
vascular disorder which results in brain injury
What is ischaemia? (stroke)
insufficient or lack of blood flow to the brain
What is an infarction? (stroke)
tissue death due to inadequate blood supply
What is infarct? (stroke)
area of damaged or dead tissue from infarction
What is penumbra? (stroke)
tissue surrounding infarct which may recover or die
What is excitotoxicity? (stroke)
Excess activity in glutamate signalling pathways (NMDA receptors) resulting in cell death.
What is oedema? (stroke)
swelling of brain
What are some signs of a stroke?
- weakness/numbness
- hard to speak or understand
- loss of balance
- loss of vision
- headache
- difficulty swallowing
What are some factors involved in stroke recovery?
- type of stroke
- size of blood vessel
- remaining intact vessels
- premorbid factors (age)
- location
Which kind of stroke is often associated with poorer recovery?
hemoragic stroke
If stroke is restricted to one area:
Outcome may be better as blood flow via alternative route
What are the two main types of stroke?
- obstructive (ischaemic) stroke
2. hemorrhagic stroke
What occurs in an obstructive stroke?
reduction of blood flow or complete blockage of a blood vessel (often fatty plaque)
What occurs in a haemorrhagic stroke?
result from bleeding into brain tissue (rupture of blood vessel)
often fatal
In obstructive strokes, what are the two main causes?
- thrombosis blood clot
2. embolism (part of a broken thrombus which blocks a blood vessel in the brain)
What does onset of obstructive stroke look like?
-cann occur suddenly, often takes 30 minutes to developed
What is recovery like for obstructive strokes?
- 80% show significant improvement
- 50% significantly disables
- around 3 months there is usually little further improvement
Most thrombotic strokes occur where?
In internal carotid or vertebral-basilar arteries