到拥挤不堪的商场、空气流通不畅的影院与去森林或空旷的田野游玩,会给人两种明显不同的感觉。造成这种感觉差异的原因不外乎空气中氧含量的多少。缺氧不仅会造成体力、脑力疲劳,还会引起许多疾病。 大脑是人体神经系统的最高指挥中枢,也是人体意识思维活动的发源地。脑的平均重量为1400克,占体重的2.5～3％,而脑的血液灌流量却占心排出量 To overcrowded shopping malls, poorly ventilated cinemas and visits to forests or open fields give two distinctly different feelings. The reason for this feeling of difference is nothing more than how much oxygen in the air. Hypoxia not only causes physical, mental fatigue, but also causes many diseases. The brain is the highest command center of the human nervous system, but also the birthplace of human consciousness and thinking activities. The average weight of the brain is 1400 grams, accounting for 2.5 to 3% of body weight, while the brain’s blood perfusion accounts for cardiac output