Distribution and Function of Water
Start with the big picture
Total body water is not uniform across the body or across life stages. It is divided mainly between intracellular fluid and extracellular fluid, with the latter further distributed among interstitial fluid, plasma, and transcellular spaces. These compartments have characteristic electrolyte patterns, including potassium and magnesium predominance inside cells and sodium in extracellular fluid. Water also serves as a solvent and reaction medium, supports nutrient and waste transport, helps maintain cell volume, and contributes to thermoregulation, lubrication, and cushioning. The lesson links these roles to water turnover and regulation of osmolarity, then considers why changes in body water can affect physiological function.
What you'll learn
- Describe how body water is distributed among major fluid compartments.
- Identify the characteristic major cations and anions of intracellular and extracellular fluid.
- Explain how water supports transport, cellular stability, and physiological processes.
- Summarize water turnover and the role of homeostatic regulation.
- Relate water imbalance to potential functional consequences.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
