Bloody supply to the brain & stroke Flashcards
Why is CONTINUOUS bloody supply to the brain so important?
Brain cells = highest energy needs
Cells in the cortex are HIGHLY susceptible to oxygen deprivation and therefore die quickly.
Where does bloody supply to the brain begin?
The aorta
What are the two pairs of arteries that supply blood to the brain
Internal carotids (left and right) take 80% Vertebral arteries supply 20%
Which arteries supply the anterior part of the brain?
The internal carotids
Which arteries supply the posterior part of the brain?
The vertebral arteries
Where do the vertebral arteries converge? What forms?
At the brainstem
The bailer artery forms (which supplies the brain stem)
What does the Basilar artery split into?
The left and right posterior cerebral arteries
What do the internal carotids split into?
The anterior and middle cerebral arteries
What area of the brain is supplied by the posterior cerebral arteries?
The occipital lobe
Which area of the brain is supplied by the middle cerebral artery?
Entire lateral surface of the brain
- language regions
- primary motor and sensory cortex
Therefore blockage = extensive damage
What is the purpose of the Circle of Willis?
Co-lateral supply - It allows some blood supply even if there’s a blockage
Which area of the brain is supplied by the anterior cerebral artery?
Pre-frontal cortex - higher order thinking/functions Lower limbs (leg and foot)
Which area of the brain is supplied by the posterior cerebral artery?
Medial temporal lobe (contains hippocampus)
Part of the temporal lobe and the occipital lobe
- Damage to visual areas = blindness/alexia
Which area of the brain is supplied by the vertebral artery?
Medulla and cerebellum
Define stroke
A vessel of the brain either bleeds or is blocked, causing part of the brain to be deprived of oxygen
What is an ischemic stroke?
Lack of blood flow to the brain tissue depriving it of the oxygen/nutrients it needs
What is a haemorrhagic stroke?
The bleeding of a vessel, which releases blood into the brain and intracranial spaces.
Causes localised and generalised pressure on brain tissue
What is a thrombosis?
Obstruction of blood flow due to localised occlusive processes - i.e. the vessel narrows so much that blood can no longer flow through
What is an embolism?
Material from elsewhere in the blood system lodges in an artery and blocks blood flow
What is an intracerebral haemorrhage?
What are some of the causes?
Bleeding from a blood vessel WITHIN the brain
High BP weakens artery walls - greater chance of vessel bursting
What is an aneurysm?
Ballooning of the artery to form a “sack” where blood gathers. If the aneurysm bursts, a haemorrhage results
What is a TIA?
Transient Ischemic Attack "mini stroke" Temporary blockage of a brain vessel Symptoms last from seconds - 24 hours Still a medical emergency - could be a warning sign of a larger stroke on the way
Why is early intervention important in stroke rehabilitation?
The surrounding brain tissue can be recovered with quick and effective treatment
