In biology, tissue fluid or interstitial fluid is understood to mean body fluids in the intercellular space that are usually not separated , i.e. lymph , hemolymph and the like. The blood of vertebrates , because it circulates in a closed vascular system , is not a tissue fluid. At about 13 liters, the interstitial fluid makes up about 75% of the volume of the extracellular fluid .
Liquid tissue and tissue fluids are often indistinguishable from one another, with liquid tissues differing significantly from conventional ones in terms of their spatial freedom and their transport function .
- Walter F. Boron, Emile L. Boulpaep: Medical Physiology, 2nd Updated Edition E-Book. Elsevier Health Sciences, 2012, ISBN 978-1-455-71181-9 , p. 106.