Lymphatic System Facts



  • The lymphatic system is your body’s sewer, the network of pipes that drains waste from the cells.
  • The ‘pipes’ of the lymphatic system are called lymphatics or lymph vessels.
  • The lymphatics are filled by a watery liquid called lymph fluid which, along with bacteria and Waste chemicals, drains from body tissues such as muscles.
  • The lymphatic system has no pump, such as the heart, to make it circulate. Instead, lymphatic fluid is circulated as a side effect of the heartbeat and muscle movement.
  • At places in the lymphatic system there are tiny lumps called nodes. These are filters which trap germs that have got into the lymph fluid.
  • In the nodes, armies of white blood cells called lymphocytes neutralize or destroy germs.
  • When you have a cold or any other infection, the lymph nodes in your neck or groin, or under your arm, may swell, as lymphocytes fight germs. This is sometimes called ‘swollen glands.
  • Lymph fluid drains back into the blood via the body’s main vein, the superior vena cava (see heart).
  • The lymphatic system is not only the lymphatics and lymph nodes, but includes the spleen, the thymus, the tonsils and the adenoids (see the immune system).
  • On average, at any time about I to 2 liters of lymph fluid circulate in the lymphatics and body tissues.
  • Lymphocytes are white blood cells that play a key role in the body’s immune system, which targets invading germs.
  • There are two kinds of lymphocyte – B lymphocytes (B-cells) and T lymphocytes (T-cells).
  • B-cells develop into plasma cells that make antibodies to attack bacteria such as those which cause cholera, as well as some viruses (see antibodies).
  • T-cells work against viruses and other micro-organisms that hide inside body cells. T-cells help identify and destroy these invaded cells or their products. They also attack certain bacteria.
  • There are two kinds of Tcell – killers and helpers.
  • Helper T-cells identify invaded cells and send out chemicals called lymphokines as an alarm, telling killer T-cells to multiply.
  • Invaded cells give themselves away by abnormal proteins on their surface.
  • Killer T-cells lock on to the cells that the helpers have identified, then move in and destroy them.
  • Some B-cells, called memory B-cells, stay around for a long time, ready for a further attack by the same organism.
  • If you get flu, it is your T lymphocytes that come to the rescue and fight off the virus.