The interstitium is a vast, body-wide network of fluid-filled spaces supported by a latticework of strong, flexible connective tissue proteins like collagen and elastin.
It is found directly beneath the skin, lines the digestive tract, lungs, and urinary systems, and surrounds muscles, blood vessels, and organs.
Key details about the interstitium include:
Structure: It consists of open, interconnected interstitial spaces filled with interstitial fluid (a clear liquid that drains into the lymphatic system).
Function: It acts as a shock absorber to protect organs and tissues from tearing during movement. It also functions as an anatomical "highway" that allows fluid, nutrients, and waste to move between blood vessels and cells.
Recent Discovery: While scientists have long known about interstitial fluid, it wasn't until 2018 that advanced imaging showed these spaces form a continuous, complex, body-wide system rather than just dense, solid connective tissue.
Some researchers even categorize it as its own organ system