Cerebral vasculature Flashcards

1
Q

why is the brain v vulnerable if blood supply is impaired?

A

Although brain makes up 2% of total body weight it uses:
10-20% cardiac output,
20% body O2 consumption , 66% liver glucose
if these requirements aren’t met braincells may infarct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What structures supply blood to the brain and where do they come from

A

1) Vertebral artery ( right comes from R subclavian artery –> branch of the brachiocephalic artery . L from left subclavian artery.
2) Internal carotid arteries which split into common carotid at laryngeal prominence ( R comes from r common carotid –> branch of the brachiocephalic artery. L from left common carotid )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 branches of the aorta

A

Brachiocephalic artery
left subclavian
left common carotid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the branches of the brachiocephalic artery

A

R common carotid ( giving internal + external carotid) + R subclavian ( giving vertebral artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which foramen does the vertebral artery pass through

A

transverse foramen on vertebral body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where does the internal and external carotid artery bifurcate from the common carotid artery

A

level of laryngeal prominence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the circle of willis

A

Circle of blood vessels in the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 2 main arteries that feed the circle of willis

A

internal carotid + vertebral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the circle of willis

A

See image on docs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does the basilar artery sit

A

on the base of the pons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the middle , anterior and posterior cerebral artery supply

A

middle –> temporal + parietal lobes

anterior –> frontal +superior medial parietal lobes)

Posterior –> occipital + inferior temporal lobes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why is the circle of willis beneficial

A

can avoid blockage in any major artery ( ie internal carotid) due to compensatory flow form the other side
though not universal as communicating arteries are thin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How are sinuses created

A

Due to separation of periosteal and meningeal layers of the dura

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the superior , straight and occipital sinus drain into

A

Confluence of sinuses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the confluence of sinus drain into

A

Transverse sinus then to sigmoid sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the signmoid sinus drain into

A

Internal jugular vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the order of venous drainage in the brain

A

1) sagittal sinus
2) Confluence of sinuses
3) Transverse sinus
4) sigmoid sinus
5) IJV ( internal jugular)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

name the 3 layers of meninges in the brain

A

Dura ( periosteal , meningeal. Infoldings form falx cerebri + falx cerebelli

arachnoid mater : Subarachnoid space has CSF –> collapses onto brain if CSF not there

pia mater

19
Q

What are the 4 types of haemorrhage

A

Extradural
subdrual
subarachnoid
intracerebral

20
Q

What causes extradural bleeds

A

Trauma often to the pterion region damaging middle meningeal artery

21
Q

Why are extradural haemorrhage so dangerous

A

As arterial high pressure bleed. can increase intercranial pressure ( stripping periosteal layer away from bone) and compress brainstem
Will have immediate clinical effects

22
Q

How to spot extradural haemorrhage

A

lemon shaped spot in MRI/CT

23
Q

What causes subdural bleeds

A

ruptured veins in brain

24
Q

Why are subdural bleeds less dangerous than extradural bleeds

A

Extradural due to high pressure arterial bleed , subdural is a venous bleed at lower pressure so less blood loss

25
What should you do clinically with a patient who might have a subdural bleed
Keep patient in hospital overnight and monitor esp if head injury causes confusion / loss of consciousness as subdural bleeds present with delayed symptoms that can present overnight
26
What causes subarachnoid bleeds
Ruptured aneurysms ( often in lower brain in circle of willis
27
Risk factors for subarachnoid bleeds
Congenital aneurisms | hypertension
28
Causes of intracerebral bleeds
Spontaneous rupture of artery due to hypertension
29
What is a stroke
type of cerebrovascular accident (CVA) aka rapidly developing focal disturbance of brain function of presumed vascular origin and >24 h duration
30
What causes CVAs ( cerebrovascular accidents
15% haemorrhage | 85% thrombo- embolic ( blockage in vessels
31
What are the 4 types of stroke
Ischemic haemorrhagic transient ischaemic thromboembolic
32
What is an ischaemic stroke
occurs when blood flow is blocked by a clot or an embolism
33
What is haemorrhagic stroke
Occurs due to bursting of a blood vessel
34
what is transient ischaemic stoke
Occurs when disruption of circulation to one part of brain due to thromboembolic causes . Resolves in 24h
35
What is a thrombosis
formation of blood clot
36
What is embolism
Plugging of small vessel by material ( atherosclerotic debris) is carried from a larger vessel
37
What is a thromboembolism
formation of a thrombus elsewhere within circulation can be degenerated into an embolus, being carried within circulation into cerebral arteries. Atherosclerotic debris from the internal carotid artery can further contribute to the development of a thrombo-embolic stroke An arterial gas embolism can form within blood vessels, and travel into cerebral vasculature, potentially causing a stroke
38
symptoms for stoke
``` Think FAST Face --> cant smile , one side fallen Arms --> can't hold them up speech --> slurred time --> call 999 ```
39
Risk factors for stroke
``` Age Hypertension Cardiac disease Smoking Diabetes mellitus ```
40
What does the anterior, middle and posterior cerebral artery supply
``` 1) ant --> Supplies the para-sagittal midline of the brain and perfuses the occipital fissure Includes PMC ( premotor cortex) ``` 2) middle --> supplies a portion of the frontal lobe and the lateral surface of the temporal and parietal lobes + deep structures of the brain Includes PMC 3) post --> supplying the occipital lobe, in addition to the inferior region of the temporal lobe
41
Symptoms of anterior cerebral artery stroke
Disruption to ACA supply impacts contralateral motor control, subsequently leading to paralysis. This is due to it effecting the PMC which is sematosensory ( different areas are mapped to different parts of the body) Topographically, paralysis of the leg > arm, face. Disturbance of intellect, executive function, and judgement (abulia). Abulia = broken down frontal function Loss of appropriate social behaviour (disinhibition). 2 + 3 due to damage to frontal lobe
42
Symptoms of middle cerebral artery stroke
Classic stroke leads to contralateral hemiplegia, topographically affecting the arm > leg. As effects motor cortex and deep motor association structures hemiplegia= paralysis on one sde of teh body Contralateral hemisensory deficits (damage to primary somatosensory cortex residing in the post central gyrus). Hemianopia ( loss of one half of visual field→ Ocular systems runs back to occipital lobe which can be damaged ) Aphasia (In a left sided lesion): Broca’s and Wernicke’s area affected.
43
Symptoms of post cerebral artery stroke
A stroke will lead to visual deficits: Homonymous hemianopia (One side) and visual agnosia (inability to recognise). Due to damage to occipital lobe so loss of visual field and processing Prosopagnosia is a cognitive disorder of face perception. ( aka inability to recognise faces of ppl you’ve known for a long time)