 Did you know your body has its own version of a sewer system? A good system for handling excess water and debris is an important part of any community. It helps take away contaminated substances it might harm us. Engineers have designed great systems of pumps and pipes to help our sewer systems do these important jobs. Most of the time we barely notice these systems, unless they fail to work. P.U. It turns out your body has a similar system for dealing with excess water and contaminated substances. There are millions of tiny vessels in your body whose job it is to gather excess water, proteins, cells, and various bits of debris. This is called the lymphatic system. The water, which is leaked out of your blood vessels, is returned to the bloodstream in your shoulder so you don't blow up like a big water balloon. The pumping happens because each little lymphatic vessel has valves at each end that keep the fluid moving in the right direction. The vessel squeezes to keep the fluid moving along. This is happening in millions of little lymphatic vessels in your body every minute of every day. As this water is pumped back up to your shoulder, it has to be cleaned so that the bits of debris in the water stream, say if you get a cut, don't get into your bloodstream and make you sick. The lymphatic system pumps all that water through at least one lymph node. These are like tiny water treatment plants where specialized immune cells recognize and destroy the foreign debris. Voila! All clean and ready to go back into the bloodstream. Unfortunately, like any sewer system, things can go horribly wrong. Sometimes we get infections that cause the pumping to break down. This can cause your arms or legs to swell to huge proportions. That's a disease called lymphoedema, and it is no laughing matter. Sometimes the debris or other bad substances can make it pass lymph nodes. Sometimes cancer cells do this and spread the cancer to other parts of the body. Bad news. For now, we wish you all the best for your lymphatic health, which you can help maintain by drinking lots of water and exercising. Keep on pumping!