Major fluid compartments. Intracellular fluid (ICF) is fluid within cells. Extracellular fluid (ECF) is fluid outside of cells. The ECF includes interstitial fluid surrounding the cells, and plasma, the fluid component of blood. (In addition, specialized ECF includes synovial fluid, CSF, aqueous fluid in the eye, and some specialized GI secretions.) Fluid continually moves between the major compartments.
IV Solution Chart: Hypotonic, Isotonic, and Hypertonic Solutions. The tonicity of the solution impacts the cells. Hypotonic solution causes excess H2O to enter the cell, potentially causing the cell to lyse. Hypertonic solution causes H20 to leave the cell, leading to flaccidity. Isotonic promotes fluid balance between the intracellular and extracellular area.