1b// Cerebral Vasculature and Cerebrovascular disorders

Question 1

why is the brain vulnerable if blood supply is impaired?

Answer 1

6% of liver glucose, 10-20% of all cardiac output - 20% of all body O2 consumption despite being only 2% of body weight

Question 2

what are the main blood supplies for the brain?

Answer 2

vertebral arteries

internal carotid arteries from common carotid

Question 3

what is the main cerebral branch of the internal carotid artery?

Answer 3

middle cerebral artery

Question 4

what artery sits on the pons?

Answer 4

basilar artery

Question 5

what artery connects the posterior cerebral artery and the middle cerebral artery?

Answer 5

posterior communicating artery

Question 6

what artery connects the anterior communicating cerebral artery and middle cerebral artery?

Answer 6

anterior cerebral artery

Question 7

what do the vertebral arteries connect to form?

Answer 7

basilar artery

Question 8

Label.

Answer 8

Circle of Willis

Question 9

where is the confluence of sinuses?

Answer 9

at the base of the occipital bone, medially.

Question 10

what does the sigmoid sinus eventually become?

Answer 10

internal jugular vein

Question 11

Describe the venous drainage of the brain.

Answer 11

cerebral veins–> venous sinuses in the dura mater–> internal jugular vein

Question 12

Label.

Answer 12

Question 13

What are the 4 types of haemorrhages?

Answer 13

extradural
subdural
subarachnoid
intracerebral

Question 14

What is an extradural haemorrhage?

Answer 14

trauma, immediate clinical effects (arterial, high pressure)

on skull

Question 15

What is a weak spot for an extradural haemorrhage?

Answer 15

pterion

truma leads to a burst in the middle meningeal artery

Question 16

What is a subdural haemorrhage?

Answer 16

trauma, can be delayed clinical effects (venous, lower pressure)

Dura mater

Question 17

What is a subarachnoid haemorrhage?

Answer 17

ruptured aneurysms

in subarachnoid space

Question 18

what is an intracerebral haemorrhage?

Answer 18

spontaneous hypertensive

in brain

Question 19

what is a cerebrovascular accident (CVA)? And what are the types?

Answer 19

rapidly developing focal disturbance of brain function of presumed vascular origin and of >24hr duration

thrombo-embolic (85%) or haemorrhage (15%)

majority of strokes are thrombo-embolic

Question 20

What is a transient ischaemic attack?

Answer 20

“rapidly developing focal disturbance of brain function of presumed vascular origin that resolves completely within 24 hours”

Question 21

what is an infarction?

Answer 21

degenerative changes after losing blood supply/occlusion of an artery

Question 22

what is cerebral ischaemia?

Answer 22

lack of sufficient blood supply to nervous tissue resulting in permanent damage if blood flow is not restored quickly

Question 23

what is a thrombosis?

Answer 23

formation of a blood clot

Question 24

what is an embolism?

Answer 24

plugging of small vessel by material carried from larger vessels e.g thrombi from the heart, atherosclerotic debrias from the internal carotid, air, fat

Question 25

what is the difference between embolism and thrombosis?

Answer 25

a thrombosis is a type of embolism (a blood clot that may travel and cause embolism)

Question 26

what are the risk factors for a stroke? (5)

Answer 26

``` AGE hypertension cardiac disease smoking diabetes mellitus ```

Question 27

What is the public health initative for strokes?

Answer 27

Question 28

what is a perfusion field?

Answer 28

region of the brain a specific vessel is responsible for providing o2 to

Question 29

what is the perfusion field for the middle cerebral artery?

Answer 29

most of the lateral surface of the cerebral cortex and subcortical deep structures

Question 30

what is the perfusion field for the anterior cerebral artery?

Answer 30

medial part of cerebral cortex

Question 31

what is the perfusion field for the posterior cerebral artery?

Answer 31

occipital lobe laterally extending to below the thalamus medially (inferior temporal)

Question 32

how does an occlusion of the anterior cerebral artery present? (3)

Answer 32

paralysis of contralateral LEG, arm, face disturbance of intellect, judgement and executive function loss of appropriate social behaviour

Question 33

how does an occlusion of the middle cerebral artery present? (5)

Answer 33

classic stroke contralateral hemiplegia arm> leg contralateral hemisensory deficits hemianopia aphasia if left sided lesion

Question 34

Answer 34

Question 35

how does an occlusion of the posterior cerebral artery present? (3)

Answer 35

visual defects - homonymous hemianopia, visual agnosia, prosopagnosia

Question 36

Answer 36

right middle cerebral artery

Question 37

path of venous drainage of the brain

Answer 37

inferior/superior sagittal sinus --> confluence of sinuses --> Great cerebral vein --> straight sinus --> confluence of sinuses --> Transverse sinus --> sigmoid sinus --> jugular foramen--> internal jugular vein

Question 38

what are the venous sinuses of the brain

Answer 38

``` inferior/superior sagittal sinus straight sinus confluence of sinuses transverse sinus sigmoid sinus ```

Question 39

how does venous blood drain in the cerebral cortex itself

Answer 39

though dura mater forming dural venous sinuses