Cl-) and ↓ small cation concentration (e.g.
Cl- and HCO3-) ▫ Solutes and water travel between the interstitial fluid and plasma through pores in endothelial cells of capillaries ▫ Negative plasma proteins are too big to travel through pores electroneutrality is maintained by repelling small anions into interstitial fluid and attracting small cations into plasma (Gibbs–Donnan effect) → interstitial fluid has ↑ small anion concentration (e.g.
ATP) Extracellular fluid ▪ Includes interstitial fluid (around cells) and plasma (aqueous part of blood, containing about 10% proteins e.g. Na+K+ ATPases establish high concentration of K+ inside cell and high concentration of Na+ outside cell) Intracellular fluid ▪ Dissolves cations (esp. NOTES NOTES FLUIDS IN THE BODY BODY FLUID COMPARTMENTS /body-fluid-compartments GENERAL CHARACTERISTICS ▪ Fluid divisions in body ▫ Includes intracellular fluid, extracellular fluid ▪ “60-40-20 rule” ▫ Total body water is 60% of body weight, of which two thirds is intracellular → total intracellular fluid is 40% of body weight, total extracellular fluid is 20% of body weight ▪ Due to macroscopic electroneutrality principle, fluid compartments have same concentration of positive charges as negative charges INTRACELLULAR & EXTRACELLULAR FLUID ▪ Large difference between intracellular fluid and extracellular fluid (e.g.