IGNIS | Page 15

Immune Response Your lymphatic system generates cells called lymphocytes, which are also found in your blood, as well as macrophages. These are what make up your immune system. B lymphocytes learn information from the surface of invading bacteria that they use to recognise other similar bacteria and Macrophages engulf and ingest invading bacteria. When a pathogen is recognised, B lymphocytes are activated and begin dividing themselves into memory cells and plasmatic cells. Memory cells hold on to the antigen information and when there is a new invasion they begin dividing rapidly in order to deal with it. The plasmatic cells secrete thousands of special antibody molecules per second, which the blood then carries to wherever the infection is. The antibodies are also known as immunoglobin and they are special protein molecules that are the shape of a Y. Each Y's arms are unique to a particular type of antibody, and each specific antibody attaches with these arms to a specific antigen. These antibodies are there to mark out invaders so that macrophages can destroy them. Lymphatic Network As your blood passes through the tissues in your body, it enters capillaries to transfer nutrients, gases and waste. Blood plasma also diffuses through the capillary walls and enters the spaces between cells in the tissue. Although some of this plasma diffuses back into the blood, some of the fluid becomes embedded. To prevent the build up of these excess fluids, small vessels called lymphatic capillaries also extend into these tissues to absorb these fluids and return them back to circulation around the body. This liquid left in the tissues is called lymph. Lymph is very similar to plasma – it is mostly water and contains proteins, cellular waste and hormones. It also contains bacterial cells that are picked up from diseased tissues in the body, as well as the white blood cells that are fighting these pathoge