Our bodily fluids. The fluid within our body is a miraculous thing that makes our life possible. It is the fluid that circulates the red and white blood cells throughout our vascular system. Our arteries and veins. That same fluid leaks out of our vascular system at the capillary beds into the interstitial spaces where our arteries and veins meet. It is also called tissue fluid. A solution that bathes and surrounds the cells of multicellular animals. As interstitial fluid begins to accumulate, it is gathered up and removed by minute lymphatic vessels and returned to the blood. As soon as the interstitial fluid enters the lymph capillaries, it is called lymph. Same thing, different space. Returning this fluid to the blood prevents edema and helps to maintain normal blood volume and pressure. During this three-part transitional phase, this fluid bathes our cells in oxygen and nutrients while also picking up cellular debris for clearance back into our general circulation where it can be filtered by our lymph nodes and filter organs like the liver, kidneys, and spleen.
What is the difference between our blood, interstitial fluid, and lymphatic fluid? Nothing but location, purpose, and small amounts of other minute contents.
It is also the yellow part of our urine, the fluid that bathes our brain, fills our eyes, and we swim around in it while developing from embryo to newborn child.
-Michael J. Loomis