脑为维持生命机能和意识活动的最重要器官,需充分的血氧和能量供应,脑血流是保证大脑进行正常生理活动的必要条件。脑的能量在正常情况下主要靠葡萄糖氧化供应,其中90%能量作为神经冲动传递和维持离子速度(主动运转)需要。脑的需氧最大,且连续不断,平时脑组织又缺乏氧的储 The brain is the most important organ for the maintenance of vital functions and conscious activities. It requires adequate blood oxygenation and energy supply. Cerebral blood flow is a necessary condition for normal brain activity. The brain’s energy is normally supplied by glucose oxidation under normal conditions, of which 90% of the energy is needed as a nerve impulse to transmit and maintain the ion velocity (active operation). Aerobic brain largest and continuous, and usually lack of brain tissue oxygen storage