The immune system is required for survival but it is most often neglected until one becomes sick. If the immune system begins to act up it may lead to conditions ranging from cold hands and diarrhea to more severe conditions such as pneumonia and Crohn’s disease.
As the first line of defense in the body the immune system functions to protect against invaders such as viruses, bacteria, and other foreign bodies. It is made up of a network of cells and tissues that target pathogens found in the body, and is also responsible for removing dead and faulty cells from the body. White blood cell leukocytes for the most part are most essential to the immune system and can be divided into 2 main types: Lymphocytes cells that remember invaders; and phagocytes cells surround, absorb and/or break down pathogens. The immunes system can distinguish itself from nonself by detecting proteins on cell surfaces, when an antigen is encountered and is recognized by cells an immune response is triggered to eliminate the invader.
