what are at least two critical functions that fluid within the body provides
The extracellular fluid provides the medium for the exchange of substances between the ECF and the cells , and this can take place through dissolving , mixing and transporting in the fluid medium . Substances in the ECF include dissolved gases , nutrients , and electrolytes , all needed to maintain life . The ECF also contains materials secreted from cells in soluble form , but which quickly coalesces into fibres ( e.g. collagen , reticular , and elastic fibres ) or precipitates out into a solid or semisolid form ( e.g. proteoglycans which form the bulk of cartilage , and the components of bone ) . These and many other substances occur , especially in association with various proteoglycans to form the extracellular matrix or the `` filler '' substance between the cells throughout the body . These substances occur in the extracellular space , and are therefore all bathed or soaked in ECF , without being part of the ECF