The vascular system
Reading instructions
To get the most out of this learning tool, please read:
Bear, Mark F, Connors, Barry W., Paradiso, Michael A. Neuroscience : exploring
the brain. - 2 ed.
Chapter 7 page 163-252
Illustrations and anmimation
Vascular
system
About 20% of the total blood volume circulates in the brain although
it represents 2% of the body weight.
Arterial supply
The circle of Willis/circulus Willisi is a circle of arteries that
gives rise to all the cerebral arteries. It gets its arterial blood
from the two internal carotid arteries/arteria carotis interna
and the two vertebral arteries/arteria vertebralis. The carotid
artery gives rise to the middle cerebral artery/a.cerebri media
on each side and are interconnected via the anterior cerebral arteries/a.cerebri
media on both sides and the anterior communicating artery/a.communicans
anterior in the front. The internal carotid arteries are also connected
to the posterior cerebral artery/a,cerebri posterior from the basilary
artery/a.basilaris by the two posterior communicating arteries/a.communicans
posterior. The posterior inferior cerebellary artery/a.cerebellaris
inferior posterior arises from the vertebral artery whereas the
anterior inferior cerebellary artery/a.cerebellaris anterior inferior
and the superior cerbellary arteries originate from the basilary
artery/a.basilaris. Functionally the anterior cerebral artery and
its branches supplies the anterior frontal lobe and the medial
portion of the hemispheres. The middle cerebral artery supplies
much of the lateral aspects of the hemispheres as well as deep
structures in the lateral cerebrum. The posterior cerebral artery
curves around the brainstem and supplies the occipital lobe and
the lower portion of the temporal lobe.
Venous drainage
The venous drainage of the brain includes the dural venous sinuses,
the veins of the brain interior, the dural meningeal veins and the
diploic veins.