Upload
carter
View
45
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Blood Supply. Human Neurobiology ANHB 2217 Avinash Bharadwaj Semester 1, 2006 Week 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 - PowerPoint PPT Presentation
Citation preview
Blood Supply
Human Neurobiology ANHB 2217
Avinash Bharadwaj
Semester 1, 2006Week 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
Cerebrovascular Disease
Narrowing of arteries (Stenosis)
Blocks in arteries “Plaques” and thrombi Emboli
Rupture Weak wall / High Pressure Aneurysm
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
Blocks and Bleeds
Blockage of an artery 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
2
3
Main Arterial Channels
Internal carotid
Vertebral(“Vertebro- basilar”)
Arterial Cast
Internal carotid
Vertebral(“Vertebro-basilar”)
Arterial Circle (of Willis)
Vertebral
Basilar
ICA ACA
MCA
PCA
SCA
AICA
PICA
Be careful with abbreviations!
Cortical and central branches
The Arterial Circle
Can compensate for slow blockage
Can equalise pressure
Variable pattern
Compensation is not reliable!
Arteries – Courses
ACA
MCA
PCA
Cerebral Arteries
Branches of middle cerebral artery
Anterior cerebral artery and its branches
Branches of posterior cerebral artery
Arterial Territories
ACA
MCA
PCA
ACA
MCA
PCA
Superolateral surface Medial surface
Think in terms of lobes and (later), functional areasLocalisation an important part of diagnosis.
Cortical and Central…
Cortical Longer, spread over the
surface
Central 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
ALPM
PL
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
Spinal Arteries
Begin from the vertebral Anterior spinal artery (2 1) Posterior spinal arteries
Reinforced by segmental arteries
Last slide!