1. Human Neurobiology ANHB 2217 Avinash Bharadwaj Semester 1, 2006 Week 2
Blood Supply
Human Neurobiology
ANHB 2217
Avinash Bharadwaj
Semester 1, 2006
Week 2

2. Blood Vessels of CNS Nervous tissue – high metabolic needs
One-fiftieth of body weight
One-sixth of circulating blood volume
One-fifth of oxygen consumption
Extreme sensitivity to reduction or loss
Seconds and minutes…!
The nature of arteries to the brain
Thin walls
Susceptibility to vascular diseases

3. Cerebrovascular Disease
Narrowing of arteries (Stenosis)
Blocks in arteries
“Plaques” and thrombi
Emboli
Rupture
Weak wall / High Pressure
Aneurysm

4. Cerebrovascular Disease
“Atheromatous change”
Rough surface – clotting of blood (thrombosis)
Clot or other matter coming in from elsewhere – embolus
Blood clots dislodged from other parts
Fat from fractures

5. Blocks and Bleeds Blockage of an artery Bleeding (Haemorrhage)
Transient or total
End arteries – no collateral circulation
“Infarct”
Bleeding (Haemorrhage)
Damage can be extensive
Bleeding outside the brain but within cranial cavity… pressure
Strokes and transient ischaemic attacks 1 3 2

6. Main Arterial Channels
Internal
carotid
Vertebral
(“Vertebro-
basilar”)

7. Arterial Cast
Internal
carotid
Vertebral
(“Vertebro-basilar”)

8. Arterial Circle (of Willis)
ACA
ICA
MCA
Cortical and central
branches
PCA
Basilar
SCA
AICA
Vertebral
PICA
Be careful with abbreviations!

9. The Arterial Circle Can compensate for slow blockage
Can equalise pressure
Variable pattern
Compensation is not reliable!

10. Arteries – Courses
ACA
PCA
MCA

11. Cerebral Arteries Branches of middle cerebral artery
Anterior cerebral artery and its branches
Knowledge of these territories, combined with a knowledge of what areas of cortex do what (a later lecture) can provide the clinician with a good idea of where a blockage has occurred.
The striatum has a major role in motor control, damage to the fine arteries here can cause motor problems.
Branches of posterior cerebral artery

12. Arterial Territories
ACA
ACA
MCA
PCA
PCA
MCA
Superolateral surface
Medial surface
Think in terms of lobes and (later), functional areas
Localisation an important part of diagnosis.

13. Cortical and Central… Cortical Central Longer, spread over the surface
Short, slender
Groups Anterior and posterior (medial + lateral in each group)
“Perforated substance”
Supply deeper structures including basal nuclei, diencephalon, internal capsule and even midbrain AM AL PM PL

14. Brainstem and Cerebellum
Vertebrobasilar system
“Cerebellar” arteries
Supply cerebellum and parts of brainstem
Two inferior (“PICA” and “AICA)
One superior
Medullary, pontine and mesencephalic branches

15. Spinal Arteries Begin from the vertebral
Anterior spinal artery (2  1)
Posterior spinal arteries
Reinforced by segmental arteries
Last slide!