It seems strange that scientists would discover a new organ in this day and age, but it just goes to show that we always have more to learn! Meet the interstitium. This tissue is found in the body’s connective tissue, including the skin’s dermis, digestive tract, lungs, urinary systems, and surrounding muscles. More than two-thirds of the human body is water - most of that contained within the cells. Some is outside the cells and is known as “interstitial” fluid, a Latin word meaning “between the other places.” Researchers previously thought these tissue layers were simply a layer of connective tissue. Connective tissue typically has very few cells and instead is mostly constructed of various cartilage and other fibers that together form a strong structure that holds your organs in place, or that connects one bone to another, or a muscle to a bone.  Recent new findings reveal that this tissue is more like an “open, fluid-filled highway” (Dr. Neil Theise, professor of pathology at NYU Langone School of Medicine). It contains interconnected, fluid-filled sacs held together by strong, flexible tissue filled with functioning proteins. 

These findings are significant concerning research involving the lymphatic system. It’s not an official organ yet, but it’s on it’s way to the classification. For it to be called an organ, more research needs to be done that agrees it works alone for a specific purpose.