生物体的生命活动一刻也离不开水，生物细胞生存于各种体液所形成的环境中。然而生物细胞对于体液酸碱性的变化非常敏感，当体液ｐＨ值偏离其正常范围时，将使细胞代谢发生障碍，甚至有生命危险。本文着重介绍了生物体液如何能抵御外界因素的影响而维持其正常的ｐＨ值范围。 Biological life moments can not do without water, biological cells survive in a variety of body fluids formed by the environment. However, the biological cells are very sensitive to the changes of the pH value of the body fluid. When the pH value of the body fluid deviates from its normal range, cell metabolism will be impeded and even life-threatening. This article focuses on how biological fluids can withstand the effects of outside factors while maintaining their normal pH range.