Circulation of the Brain Flashcards
What is the circle of willis?
occlusion of one internal carotid does not necessarily result in a stroke
brain may be protected from bilateral carotid occlusion through basilar supply
What is a penetrating injury?
something goes into your head
risk of infection
What is a compression injury?
causes inner cerebral trauma
blow to head
What is a deceleration injury?
outer cerebral injury
discrete cognitive deficit
lesion at front and back
What is a diffuse axonal injury?
results in poor communication between brain structures
reduced processing speed
global impairment
What is secondary damage?
raised ICP- distortion of brain
infection
ischeameic changes
complications of systemic dysfunction
What is a stroke?
a rapidly developed clinical sign of focal disturbance of cerebral function of presumed vascular origin and of more than 24 hrs duration
What is a haemorrhage?
bleeding from one of the cereal arteries
What is a subarachoid haemorrhage?
bleeding into the subarachnoid space
due to a rupture of a cogenital aneurysm, tangling of blood vessels or trauma
sudden intense headache, vomting, neck stiffness, loss of consciousness
10 % die in 2 hours
40% die in 2 weeks
What is a intracerebal haemorrhage?
bleeding into deeper parts of the brain
associated with long-standing hypertension
arterial walls weaken- micro aneurysms develop which rupture and bleed
severe headache and vomiting
What is a extradural haemorrhage?
bleeding into extradural space
caused by severe trauma- tearing meningeal artery
squashing of the brain
What is a subdural haemorrhage?
bleeding into subdural space often caused by trauma may be interval between injury and symptoms headache, drowsiness coma
What is a ischaemia?
blood vessel is blocked so part of the brain dies due to a lack of oxygen
80% due to occlusion
What is an embolic stroke- completed stroke?
sudden onset
What is an embolic stroke- TIA?
repeated small emboli, no infarction occurs as blood pushes it on
What is an embolic stroke-embolism?
pieces of plaque can break free, travel to the brain and block blood vessels that supply blood to the brain- leads to an ischemic stroke
What is an embolic stroke- atrial fibrillation?
embolus clot which blocks blood flow to the part of the brain leading to a stroke
Where does the middle cerebral artery supply?
brocas area for speech
basal ganglia
internal capsule for motor and sensory pathways
sensorimotor cortex
What does the anterior cerebral artery supply?
frontal lobe
medial part of sensorimotor cortex
What does the posterior cerebral artery supply?
occipital lobe
medial aspect of temporal lobe
thalamus
visual and memory problems
What is the basilar artery?
nuclei of the cranial nerve- damage to this can result in sensory messages not getting up to the brained motor message not going down- locked in syndrome
What does blood supply to the brain do?
ensures continuous blood supply of oxygen and glucose of the brain
removal of waste (CO2, lactic acid)
any disruption can lead to a loss of consciousness with seconds of irreversible damage
What does auto regulation do?
enables blood supply to remain constant
occurs between mean arterial pressure of 60-150mmHg
intracranial pressure remains constant
increase in bp causes a constriction of arteries in the brain to slow down blood
an increase in CO2 leads to dilation of arterioles in the brain to get ride of CO2
What can failure of auto regulation lead to?
trauma
acute stroke
tumours
inflammation
