intracellular fluid

intracellular fluid, substance within living cells that is made up primarily of water and molecules such as dissolved ions and is a major component of the cytoplasm and cytosol. A variety of chemical reactions within cells take place in the cytoplasm and therefore the intracellular fluid. The intracellular fluid bathes cellular organelles, and, in adult humans, it accounts for about 40 percent of total body weight. Intracellular fluid is distinguished from extracellular fluid, which is...