Blood supply

Question 1

What % of the following does the brain use

a) Cardiac output
b) total body oxygen
c) total body glucose

Answer 1

a) 15%
b) 20%
c) 25%

Question 2

What is average brain blood flow

Answer 2

46ml/100g/min

Question 3

How many seconds of anoxia lead to unconciousness

Answer 3

20

Question 4

Describe structure of arteries in the brain

Answer 4

Thin walled so easily blocked distorted or ruptured

Question 5

Describe structure of veins in the brain

Answer 5

Thin walled so no muscles or elasticity to help return

Question 6

What causes increased flow to the brain

Answer 6

Increased CO2

Reduced 02

Question 7

What % change in CO2 is needed to double blood flow to the brain

Answer 7

70

Question 8

Which arteries provide cerebral blood flow and in what proportion

Answer 8

80% from carotids

20% from vertebrals

Question 9

2 common variations of the circle of willis

Answer 9

One posterior communicating small, one large

Anterior communicating large

Question 10

What artery do striate come off and what do they supply

Answer 10

Internal capsule, lentiform nucleus etc

Come off middle cerebral

Question 11

What artery supplies majority of lateral surface of brain

Answer 11

Middle cerebral artery

Question 12

What does the basilar artery supply

Answer 12

Pons and cerebellum

Question 13

What does the posterior cerebral artery supply

Answer 13

Inferior and medial aspects of temporal and occipital cortex
Thalamus and posterior internal capsule
Midbrain

Question 14

What does the vertebral artery supply

Answer 14

Spinal cord

Dorsal medulla of brainstem (PICA)

Question 15

Where do superficial cerebral veins cross

Answer 15

Subarachnoid space

Question 16

What is the function of arachnoid granulations

Answer 16

Allow CSF to flow into venous blood of sinuses but prevent backflow of blood into sub arachnoid space

Question 17

Causes of ischaemic strokes

Answer 17

Atherosclerosis

Embolism

Question 18

Causes of cerebral haemorrhage

Answer 18

Trauma

Spontaneous (haemorrhagic shock)

Question 19

What happens in an MCA stroke, dominant hemisphere

Answer 19

Global aphasia

Sensorimotor loss on contralateral face, upper limb and trunk

Question 20

What happens in an MCA stroke non dominant hemisphere

Answer 20

Neglect syndrome

Question 21

What happens in a stroke that affects ACA

Answer 21

Contralateral sensorimotor loss below waist
Urinary incontinence
Personality defects

Question 22

What happens in a stroke that affects PCA

Answer 22

Contralateral homonymous hemianopsia
Reading and writing defects
Impaired memory

Question 23

What is transient ischaemic attack

Answer 23

Temporary loss of brain function <30 minutes

Question 24

What are TIA symptoms if it affects anterior circulation

Answer 24

Motor weakness
Hemi-sensory loss
Dysarthria
Transient monocular blindness

Question 25

What are TIA symptoms if it affects posterior circulation

Answer 25

Vertigo Diplopia Ataxia Amnesia

Question 26

How does extra/ epi dural haematoma present?

Answer 26

May present with lucid period immediately after trauma followed by unconciousness

Question 27

Symptoms of epidural bleed (explain them)

Answer 27

- Blood collects in compresses intracranial structures - Compress cranial nerve III - Weakness of extremities on opposite side of lesion - Loss of visual field opposite to the lesion

Question 28

Symptoms of subarachnoid haemotoma

Answer 28

Severe headache Vomiting Confusion Lowered level of conciousness

Question 29

What can be seen on CT scan of subarachnoid haemotoma

Answer 29

White signal diffuse over sulci on both sides

Question 30

Name the 3 forms of cerebral aneurysms

Answer 30

Saccular Fusiform Berry