What do you mean by intracellular fluid and external fluid?

Extracellular fluid: the body fluid existing outside cells in human body is called extracellular fluid. It mainly includes interstitial fluid, plasma (liquid part of blood), lymph and cerebrospinal fluid. , accounting for 1/3 of the total body fluids. Extracellular fluid in the human body constitutes the liquid environment on which cells in the body depend, which is called the internal environment of the human body.

Intracellular fluid: in human body, it exists in cells, and its chemical composition and content directly affect the metabolism and physiological function of cells. It is called intracellular fluid. It accounts for about 2/3 of adult body fluids (about 40% of body weight). Because human cells can't directly contact with the external environment, the environment in which cells directly contact is extracellular fluid, that is, intracellular fluid communicates with extracellular fluid through the cell membrane. Extracellular fluid mainly includes tissue fluid, plasma (non-blood), lymph and cerebrospinal fluid.