Blood supply to Brain II

Question 1

Brain % of body weight

Answer 1

2%

Question 2

How much CO does brain receive

Answer 2

15%

Question 3

How much O2 does brain use

Answer 3

20%

Question 4

How much glucose does brain use

Answer 4

25%

Question 5

Average brain blood flow

Answer 5

46mL/100g of brain per min

Question 6

How many seconds of anoxia lead to unconsciousness

Answer 6

20 seconds

Question 7

Lower O2, higher CO2

Answer 7

Increased flow

Question 8

Blood flow doesn’t change until

Answer 8

PO2 falls below 50mmHg

Question 9

Hypercapnia effects

Answer 9

Dilatation of cerebral arteries

Increased blood flow

Question 10

Hypocapnia effect

Answer 10

Constriction of cerebral arteries

Decreased blood flow

Question 11

Arteries in brain

Answer 11

Thin walled

Easily blocked, distorted or ruptured

Question 12

Veins in brain

Answer 12

No valves
Thin walled
No muscles or elasticity to help return

Question 13

Arterial BS

Answer 13

Carotid- 80%

Vertebral- 20%

Question 14

Vertebral artery

Answer 14

Posterior and anterior spinal arteries –> spinal cord

PICA –> dorsal medulla of brain

Question 15

Basilar artery

Answer 15

Pons

Cerebellum

Question 16

Posterior cerebral artery

Answer 16

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

Question 17

Arachnoid granulations

Answer 17

Allow CSF to flow into venous blood of sinuses

BUT prevent backflow of blood into subarachnoid space

Question 18

Superficial cerebral veins

Answer 18

Cross subarachnoid space
Pierce dura + enter intracranial venous sinuses
Superficial drainage

Question 19

Major causes stroke

Answer 19

Atherosclerosis
Hypertension
Aneurysm
Elderly
Head injury

Question 20

Ischaemic stroke

Answer 20

85-88%
Atherosclerosis
Embolism

Question 21

Cerebral haemorrhagic stroke

Answer 21

12-15%
Trauma
Spontaneous

Question 22

MCA stroke

Answer 22

Dominant hemisphere –> global aphasia, sensorimotor loss on contralateral face, upper limb + trunk
Striate arteries often involved
Non-dominant hemisphere –> neglect syndrome

Question 23

MCA Stroke dominant hemisphere

Answer 23

Global aphasia

Sensorimotor loss on contralateral face, upper limb + trunk

Question 24

MCA stroke non-dominant hemisphere

Answer 24

Neglect syndrome

Question 25

ACA stroke

Answer 25

Contralateral sensorimotor loss below waist Urinary incontinence Personality defects Split-brain syndrome

Question 26

PCA stroke

Answer 26

Contralateral homonymous hemianopia Reading + writing deficits Impaired memory

Question 27

TIA

Answer 27

Temp. loss brain function | Resolves within 24 hours

Question 28

TIA symptoms- Anterior circulation

Answer 28

Motor weakness Hemi-sensory loss Dysarthria Transient monocular blindness

Question 29

TIA symptoms- Posterior circulation

Answer 29

Vertigo Diplopia Ataxia Amnesia

Question 30

Epidural haematoma

Answer 30

``` Traumatic Between dura mater + skull Expansion stops at sutures because dura more tightly attached here- then presses inwards Rapid arterial bleeding Mortality 10% ```

Question 31

Subdural haematoma

Answer 31

Traumatic/ageing Blood between dura + arachnoid mater Rupture to bridging veins Mortality 40-60%

Question 32

Subarachnoid haematoma

Answer 32

Spontaneous Between arachnoid + pia Rupture aneurysm or head injury Arterial

Question 33

Epidural haematoma bleed

Answer 33

Middle meningeal | Anterior ethmoidal

Question 34

Epidural haematoma symptoms

Answer 34

Blood collection compresses intracranial structures Compress cranial nerve III Weakness of extremities on opposite side of lesion Loss of visual field opposite to lesion

Question 35

Epidural haematoma Diagnosis

Answer 35

CT MRI Convex lens

Question 36

Subdural haematoma bleed

Answer 36

Acute, subacute or chronic Acute after high speed acceleration + deceleration Slower onset as venous bleed

Question 37

Subdural haematoma symptoms

Answer 37

``` Irritability Seizures Headache Numbness Disorientation ```

Question 38

Subdural haematoma diagnosis

Answer 38

CT --> crescent shaped with concave surface | Crosses suture lines

Question 39

Cerebral arteriovenous malformation

Answer 39

``` Headaches + seizures Pulsing noise in head Progressive weakness Numbness Vision changes Debilitating, excruciating pain ```