Here are detailed lecture notes on the blood supply to the brain based on the new transcript:
Title: Blood Supply to the Brain and the Circle of Willis
I. Sources of Blood Supply
A. Internal Carotid Arteries
- Main supply for anterior circulation (cerebral hemispheres, thalamus, hypothalamus)
B. Vertebral Arteries
- Main supply for posterior circulation (brainstem and areas behind midbrain)
II. The Circle of Willis
A. Internal Carotid Arteries split into:
1. Anterior Cerebral Artery
2. Middle Cerebral Artery
B. Vertebral Arteries join to form:
1. Basilar Artery
2. Posterior Cerebral Arteries
C. Interconnecting Arteries
1. Anterior Communicating Artery
2. Posterior Communicating Arteries
D. Forms a circular interconnection
- Allows redundant blood flow channels
- Can compensate for blockages by rerouting flow
III. Importance of the Circle of Willis A. Backup Plan for Brain’s Blood Supply - Can compensate for single blockage by rerouting flow - May compensate for additional minor blockages B. If one Internal Carotid fails, the other can supply blood
IV. Location of Circle of Willis
A. Sits at the base of the brain
B. Internal Carotids visible entering from below
C. Vertebral arteries enter from foramen magnum, join into basilar artery
V. Implications
A. Congenital malformations often require surgery from below
B. Source of many cerebrovascular problems at Circle of Willis
Stroke and Tumor