Koko

1) Write 7 most important or meaningful science words that help you to understand immunology. Give a simple definition to each word. 2) In 30 minutes, showcase/demonstrate your best or deepest understanding of immunology, with explanation; begin with a question or title (e.g. how __ works?) __


 * < Word ||< Definition ||
 * < Immunity ||< To be immune to something means not to be affected by it. In scientific terminology it means that a pathogen can easily be eliminated in the body causing the carrier not to become sick. See: Pathogen. ||
 * < Leukocyte ||< Also referred to as white blood cell. There are three classes of white blood cells, with 5 subcategories. A Leukocyte patrols the body or their designated area (depending on the type of leukocyte) and fight pathogens to prevent infection. Leukocytes have different ways to eliminate pathogens, but are most known for the humoral response, which is when they use antibodies to deactivate pathogens. See: Pathogen, Antibody. ||
 * < Pathogen ||< A pathogen is a disease-causing or harmful microorganism, such as virus, bacteria, or fungus. ||
 * < Antigen ||< An antigen is a protein found on all foreign material in the body (pathogens) which trigger an immune response. Different antigens trigger different responses as not all antigens are the same. Sometimes the immune system needs time to figure out how to respond to the antigen or what antibodies to produce to eliminate the pathogen. See also: Pathogen, Antibody ||
 * < Antibody ||< An antibody is a protein released by B cells and Plasma cells (B cells evolve into plasma cells occasionally). An antibody attaches itself to an antigen. When enough antibodies are present on a pathogen (if enough antibodies attach themselves to antigens), they eliminate the pathogen. They are part of the humoral response and are the third line of defense. See also: Lines of defense, Antigen, Pathogen. ||
 * < Lines of defense ||< The lines of defense are parts of the immune system that help keep the body healthy. There are three in total. The first line of defense is made up of physical barriers, such as nails, skin, and hair. They make it hard for pathogens to enter. The second line of defense consists of white blood cells and inflammation. The third is antibodies/the humoral response. ||

How does the immune system work? The main focus of the immune system is to eliminate pathogens and to keep the body healthy. The immune system is a network of many organs and cells that eliminate foreign substances (pathogens). If a pathogen were to enter the immune system, they would have to get through the first line of defense and more. If a pathogen would enter the nose, mucus, which contains an enzyme called lysozyme, would eliminate it. Lysozyme breaks down the cell walls of most bacteria and viruses. This enzyme is also found in tears, sothat the pathogen would not be able to enter the body through the eyes. Saliva contains antibacterial substances, making the mouth a bad penetration point. The best way for a pathogen to enter would be through a cut or open wound. If a pathogen enters the body in any way, it would be detected by the many internal defenses of the immune system. If the pathogen were to go through the spleen, it would be detected, for the spleen's responsibility is to detect foreign material, along with filtering blood and replacing red blood cells. The pathogen could also go through the lymphatic system. The lymphatic system is a network of thin vessels that spreads through the body, a little like the circulatory system, but without a pump. These vessels carry lymph. Lymph is excess body liquid from the tissues in the body. When going through the system, along the way there are lymph nodes. Lymph nodes are lumps along the vessels that contain lymphocytes, a type of leukocyte (white blood cell). These eliminate foreign material found in the lymph, meaning that if a pathogen is found in body liquid and is carried through the lymphatic system, they will be eliminated. When there are many pathogens found and the lymphatic system is working hard to eliminate them, the lymph nodes swell up. This can be felt in the neck as there are many lymph nodes located there. Another way that the pathogen could be fought by the immune system is the stomach. If the pathogen enters the mouth, for example on food, then it would be carried to the stomach. The stomach's main purpose is to digest food by breaking it down with the help of digestive juices and hydrochloric acid. What these also do, however, is kill pathogens. This is only logical as thousands of microorganisms are found in food. The most common way pathogens move around, however, is through the circulatory system. Leukocytes patrol the circulatory system (they are also found in other parts of the body, however). If a leukocyte spots a pathogen, there are many ways it can respond, depending on the kind of leukocyte they are. Here is a list of some of the body's leukocytes: -Killer T cells -Helper T cells -Supressor T cells -B cells -Eosinophils -Basophils -Neutrophils -Phagocytes -Macrophages All these leukocytes fall under different classes. Here is a diagram explaining the three classes of leukocytes and their subclasses: