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. § 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