top of page

Milieu Intérieur vs Milieu Extérieur

When seen from the viewpoint of living cells in our body, there are two environments for them, milieu extérieur and milieu intérieur.

Milieu Extérieur (External Environment)
  • The physical surrounding of the whole body.

  • In simple words, it's the environment outside your skin.

  • Hostile for the individual human cell to survive.

Milieu Intérieur (Internal Environment)
  • The internal environment inside our body in which cells live.

  • Simply seen, it's the extracellular fluid inside our body.

The Border
  • The exact border that separates milieu extérieur and milieu intérieur is epithelium.

  • Examples of contents that are physically inside our body but outside the milieu intérieur:

    • Contents of the gastrointestinal tract

    • Contents of the respiratory tract

    • Contents of renal tubules, ureters, urinary bladder and urethra

    • Contents of the sweat duct


Next >>

In the next session, we will see how 'physiology' i.e. normal functioning of all cells and organs contributes to maintaining the milieu intérieur at a constant level that is favorable for the survival of the cells.


bottom of page