Blood Supply
You'll be responsible for knowing the brain arterial blood supply (i.e. the Circle of Willis) in the human brain. A diagram of the Circle of Willis is depictied in Figure 1. This set of connected arteries lies on the ventral surface of the human brain. The optic chiasm would be located within the circle (about where the number "3" is) and the spinal cord would project ventrally and parallel the vertebral arteries. Note how the blood system makes a continuous circle surrounding the optic chiasm which allows for redundant blood flow. The advantage of such a design is that it may allow collateral blood flow to compensate for obstructions in certain arteries. For a more detailed illustration please refer to diagram 9-3 in The Human Brain Coloring Book. Figure 2 is an example of how this arterial system would look laying on the ventral floor of the human brain.
Anterior
Posterior
Figure 1.
Figure 2.
1) Anterior
Communicating Artery
2) Anterior
Cerebral Artery
3) Internal Carotid
Artery
4) Middle Cerebral
Artery
5) Posterior
Communicating Artery
6) Posterior
Cerebral Artery
7) Basilar Artery
8) Vertebral Artery