Considering the fact that we’ve been writing books on anatomy for 475 years, it’s pretty remarkable that the human body is still surprising scientists.
Researchers led by a team working at the Icahn School of Medicine in New York on March 27 detailed the discovery of a previously unknown set of fluid networks in the journal Scientific Reports. These networks were found during a routine procedure of looking down a patient’s esophagus with a tiny camera, called an endoscopy, using a relatively new tool called a Probe-based Confocal Laser Endomicroscopy to take a close-up look at bile-duct tissue.
Instead of finding the tissue described in most textbooks, they found a ribbed network of collagen filaments filled with fluid. It appears that when physicians and physiologists had looked at these areas before, the tools they were using ended up compressing the collagen and squeezing out all the fluid. To confirm that this was the case, researchers then asked 12 patients undergoing surgery for other medical problems permission to dye and remove these new-found tissues during their procedure, flash-freezing the samples to examine them more closely.
In order to check the prevalence of these types of tissues, Neil Theise, a pathologist at New York University School of Medicine and lead author of the work, even stuck the same tool up his own nose, according to New Scientist. Sure enough, the fluid-filled matrix was there.
The team thinks that we have these structures all over our bodies, although it’s not clear why. One theory is that they act like cushioning, allowing our other organs to comfortably expand and contract as they carry out their day-to-day business. They may also have something to do with the way that tumors spread throughout the body. If cancerous cells are picked up through this fluid, they can get quickly picked up through the lymphatic system “like they’re on a water slide,” Theise told New Scientist. Inflammatory conditions, certain types of liver disease, and other types of swelling could also be impacted by these networks.
The jury’s out whether this network of fluid meets the criteria of an organ, though.
In some schools of thought, organs are denoted by a specific role. “The stomach, bladder, and kidneys are all self-contained areas of tissues that all work together to have one function,” Jennifer Whitney told Quartz previously. The appendix gets a pass because even though we can only theorize what it does, it can become infected. Other times, organs are thought to be basically any solid structure in the body, which would rule out blood. But blood, too, can become sick, as in the case of anemias or certain cancers.
In reality, there isn’t a single definition of an organ—it depends on the person who’s classifying them. But it doesn’t matter that much. These scientists are more focused on learning how these newly-spotted structures impact our health, and if they can be used as drug delivery or diagnostic tools.