Cerebral Blood Flow Supporting the Brain

This chapter describes how cerebral blood flow supports the brain in health and disease. Since the brain is so important it is protected by a system that maintains a stable cerebral blood flow supply. In the healthy brain, cerebral blood flow is regulated by four basic regulating mechanisms: blood pressure regulation (also known as autoregulation), chemical regulation, neurogenic regulation, and metabolic regulation. However, in diseased brain, vascular deficit of a proximal area causes a reduction in cerebral perfusion pressure (CPP) which reduces cerebral blood flow and results in misery perfusion and later luxury perfusion. In the chronic phase, circulation reserve and the metabolic reserve are decreased. With changes in pathology, such as neurodegeneration or accumulation of abnormal protein (e.g. beta-amyloid or tau protein) in distal areas, cerebral blood flow in those areas is naturally reduced.