8 2. Internal environment of the body Body fluid(60% of body weight) k Intracellular fluid(40%0) k Extracellular fluid(20%) Plasma (5%) Interstitial fluid (15%) Lymph(1%) Cerebrospinal fluid(1%) Aqueous humor(1%) etc§ 2. Internal environment of the body • Body fluid (60% of body weight) * Intracellular fluid (40%) * Extracellular fluid (20%) Plasma (5%) Interstitial fluid (15%) Lymph (<1%) Cerebrospinal fluid (<1%) Aqueous humor (<1%) etc