The lymphatic system | Health | Biology | FuseSchool

Click here to see more videos: CREDITS Animation & Design: Joshua Thomas ( Narration: Dale Bennet Script: William Haines Did you know your body has its own version of a sewer system, for removing unwanted toxins, waste and excess water from the body? This is called our lymphatic system. Like our blood circulation, the lymphatic system is made up of millions of little vessels that branch all around our body. But whereas arteries and veins carry blood, the lymphatic vessels are much, much finer and carry a colorless fluid called lymph. Our lymphatic system has 3 main duties: ONE: it contains white blood cells called lymphocytes, which are used to fight infection. TWO: it acts as a one-way drainage system, transporting fluid from body tissues into the blood circulation. THREE: it gets rid of waste products produced by cells. As blood circulates the body, plasma leaves the blood vessels and travels into the body tissues, delivering food, oxygen, and hormones to the cells. This plasma becomes tissue fluid and surrounds all of our body’s tissues. It then collects waste products, excess water, and toxins from the cells. 90% of this fluid passes back into the blood circulation. However, 10% of the fluid is left behind and is known as lymph. We, therefore, need a system to drain this lymph fluid, so that we don’t end up as a swollen fluid-filled balloon, hence the lymphatic system. The lymph fluid drains into lymph vessels, where it then travels to lymph nodes, which are found all around your body. To stop back-flow, the lymph vessels have one-way valves and muscular walls that contract to force the lymph forward. This is happening in millions of little lymphatic vessels in your body every minute of every day! The lymph nodes filter the lymph, destroying or trapping anything harmful. The lymph nodes contain white blood cells called lymphocytes, which attack and break down bacteria, viruses, damaged cells or cancer cells. This filtering and destroying is an important part of our immune system, and stops nasty substances from being fed back into our bloodstream which would make us sick. The waste products and destroyed bacteria are then carried in the lymph fluid through larger lymph vessels up to your neck, where the thoracic duct empties the lymph back into the blood circulation. The bloodstream then removes the waste products from the body, as it does with other waste. As well as the lymph fluid, lymph vessels, and lymph nodes, our lymphatic system also includes a few organs: the spleen, thymus, tonsils, and adenoids. They all have roles in helping our body fight off infections. 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. Sometimes the debris or other bad substances can make it past lymph nodes. Sometimes cancer cells do this and spread the cancer to other parts of the body, which obviously isn’t good. 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! VISIT us at, where all of our videos are carefully organised into topics and specific orders, and to see what else we have on offer. Comment, like and share with other learners. You can both ask and answer questions, and teachers will get back to you. These videos can be used in a flipped classroom model or as a revision aid. Access a deeper Learning Experience in the FuseSchool platform and app: This Open Educational Resource is free of charge, under a Creative Commons License: Attribution-NonCommercial CC BY-NC ( View License Deed: ). You are allowed to download the video for nonprofit, educational use. If you would like to modify the video, please contact us:

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