Lymphatic system

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The lymphatic system is extremely important for the normal functioning of the human organism. It is integrated into the circulatory system, with lymphatic fluid flowing from opened small capillaries at the periphery to the large central lymphatic vessels which deliver lymph to blood circulation.

One of the major tasks of the lymphatic system is to control the balance of body fluids. Whatever leaks through the blood vessels at the periphery is being collected, checked, and delivered back to blood circulation. The lymph collects not only leakage from blood vessels, but also the products of cellular metabolism and parts of damaged cellular structures. Therefore, it controls body waste products which are, through the lymphatic network, finally being delivered to the blood stream. The blood takes over the waste products and reaches the excretory organs such as the kidneys and the intestines, which are able to finally excrete these waste products. In case of a malfunction of the lymphatic system, our body would soon suffer from accumulated waste products. This is why lymph drainage is so important.  In case of drainage insufficiency, the waste products and the excess of intercellular fluid remains in the peripheral tissues, presented as swelling. This also results in immune deficiency leading to infection and inflammation, since most of the waste products and microorganisms are not being cleared off from the extracellular matrix. We can notice mild swelling almost every day if we stand still on our feet for longer periods. Swelling may also occur following certain surgical procedures. In this case, the affected extremities increase in volume and feel hard when touched. Lymphatic drainage procedures are recommended in such circumstances. Swelling shows a seasonal pattern, being most intensive during the summer period due to excessive drainage from blood vessels. This, in turn, leads to higher exterior pressure on peripheral lymphatic vessels which impede the flow of lymph through the vessels. This can be prevented by physical activity, elevating the feet, placing pillows under the calves when lying down, avoiding tight clothes with elastic straps, and taking adequate amounts of water (at least 2 liters, if not recommended otherwise due to other medical conditions). Intake of water with freshly squeezed lemon juice is especially recommended due to lemon’s alkalizing potential.

The second major task of the lymphatic system is to collect fats from the intestinal system, which were absorbed from digested food. Fats are delivered directly to the blood stream which distributes them throughout the body, without passing first through the liver. We will further elaborate the metabolism of fats and fatty acids in another text.

This brings us to the third task of the lymphatic system. The lymphatic system plays an important role in the immune defense of the human body which is constantly being attacked by microorganisms, i.e. various viruses and bacteria. Microorganisms that attack peripheral areas are filtered into very tiny lymphatic vessels. They may be ingested by defensive phagocytic cells or not. Either way, they start to flow via lymphatic pathways until they reach lymphatic nodes. This is where they come in contact with lymphatic cells (T – and B – cells) which recognize their antigens as foreign (unfamiliar). The lymphatic cells then start with their defensive tasks which should deal with any microbial attack, but also memorize their antigens to facilitate potential future defense. While we are not under attack of exterior microorganisms (steady state), the lymphatic system is constantly exercising, i.e. presenting and recognizing cells of our own body as domestic and non-hostile. This is important to avoid potential immune reaction to antigens of our own body.

Fortunately, this defense mechanism also works when tumor cells are created. The immune system does not recognize them as the host’s own cells and tries to get rid of them. Tumor cells are eliminated until the point when they potentially manage to escape or overpower the host’s defense system. This is the point when we potentially start to lose our battle against cancer.

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Unfortunately, sometimes our immune system may attack our own cells and tissues. This is the underlying mechanism of all autoimmune diseases.

It is obvious that the lymphatic system plays very important roles in our body. Any failure of the lymphatic system may lead to serious diseases.

Proper nutrition, hydration and physical activity help us to maintain the lymphatic system and its normal function.

Many methods are offered to help us improve lymph drainage including massage and an alternating hot and cold environment (hot and cold showers).

Sources:

  1. Liao S, von der Weid PY. Lymphatic system: an active pathway for immune protection. Semin Cell Dev Biol. 2015 Feb;38:83-9. doi:10.1016/j.semcdb.2014.11.012. Epub 2014 Dec 19. Review. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4397130/pdf/nihms651175.pdf
  2. Halin C, Detmar M. An unexpected connection: lymph node lymphangiogenesis and dendritic cell migration. Immunity. 2006 Feb;24(2):129-31.http://www.cell.com/immunity/pdf/S1074-7613(06)00110-5.pdf Lymph node function, dendrytic cells
  3. Chakraborty S, Zawieja S, Wang W, Zawieja DC, Muthuchamy M. Lymphatic system acts as a vital link between metabolic syndrome and inflammation.Annals of the New York Academy of Sciences. 2010;1207(Suppl 1):E94-102. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2965625/pdf/nihms228807.pdf
  4. Wiig H, Keskin D, Kalluri R. Interaction between the extracellular matrix and lymphatics – consequences for lymphangiogenesis and lymphatic function.Matrix biology : journal of the International Society for Matrix Biology. 2010;29(8):645-656. doi:10.1016/j.matbio.2010.08.001. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3992865/pdf/nihms250181.pdf