Circulation of the Brain

Question 1

What is the circle of willis?

Answer 1

occlusion of one internal carotid does not necessarily result in a stroke
brain may be protected from bilateral carotid occlusion through basilar supply

Question 2

What is a penetrating injury?

Answer 2

something goes into your head

risk of infection

Question 3

What is a compression injury?

Answer 3

causes inner cerebral trauma

blow to head

Question 4

What is a deceleration injury?

Answer 4

outer cerebral injury
discrete cognitive deficit
lesion at front and back

Question 5

What is a diffuse axonal injury?

Answer 5

results in poor communication between brain structures
reduced processing speed
global impairment

Question 6

What is secondary damage?

Answer 6

raised ICP- distortion of brain
infection
ischeameic changes
complications of systemic dysfunction

Question 7

What is a stroke?

Answer 7

a rapidly developed clinical sign of focal disturbance of cerebral function of presumed vascular origin and of more than 24 hrs duration

Question 8

What is a haemorrhage?

Answer 8

bleeding from one of the cereal arteries

Question 9

What is a subarachoid haemorrhage?

Answer 9

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

Question 10

What is a intracerebal haemorrhage?

Answer 10

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

Question 11

What is a extradural haemorrhage?

Answer 11

bleeding into extradural space
caused by severe trauma- tearing meningeal artery
squashing of the brain

Question 12

What is a subdural haemorrhage?

Answer 12

bleeding into subdural space
often caused by trauma 
may be interval between injury and symptoms
headache, drowsiness
coma

Question 13

What is a ischaemia?

Answer 13

blood vessel is blocked so part of the brain dies due to a lack of oxygen
80% due to occlusion

Question 14

What is an embolic stroke- completed stroke?

Answer 14

sudden onset

Question 15

What is an embolic stroke- TIA?

Answer 15

repeated small emboli, no infarction occurs as blood pushes it on

Question 16

What is an embolic stroke-embolism?

Answer 16

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

Question 17

What is an embolic stroke- atrial fibrillation?

Answer 17

embolus clot which blocks blood flow to the part of the brain leading to a stroke

Question 18

Where does the middle cerebral artery supply?

Answer 18

brocas area for speech
basal ganglia
internal capsule for motor and sensory pathways
sensorimotor cortex

Question 19

What does the anterior cerebral artery supply?

Answer 19

frontal lobe

medial part of sensorimotor cortex

Question 20

What does the posterior cerebral artery supply?

Answer 20

occipital lobe
medial aspect of temporal lobe
thalamus
visual and memory problems

Question 21

What is the basilar artery?

Answer 21

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

Question 22

What does blood supply to the brain do?

Answer 22

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

Question 23

What does auto regulation do?

Answer 23

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

Question 24

What can failure of auto regulation lead to?

Answer 24

trauma
acute stroke
tumours
inflammation