What is the difference between lymph and interstitial fluid?
When the interstitial fluid (extracellular fluid or ECF) enters the first lymph capillaries, it has been shown that some of the water from the interstitial compartment exits the lymph capillaries, so even at the very beginning the lymph is slightly different (at least more concentrated) than the interstitial fluid. They are clearly not the same fluids. Besides its different constitution, lymph also uses a very specific medium: the lymphatic vessels and nodes into which it acquires its specific rhythm, direction and depth.
