Fighting Disease

Harmful Bacteria Parasitism  when bacteria benefits at the expense of the host Example: Pathogen – a disease causing microorganism

Pathogenic Bacteria gain entrance into the body bacteria begins to produce toxins toxins travel through body via circulatory system results is illness/disease EXAMPLES: Tuberculosis, Typhoid, Diptheria

THREE LINES OF DEFENcE There are 3 lines of defence offered by the immune system External Defence Lymphatic System Antibody Formation

External Defence Bacteria cannot penetrate human skin Bacteria can enter through pores, wounds, openings (nasal cavity and mouth) and eyes Nasal Cavity and pharynx have cilia and mucus that will trap bacteria In eyes, bacteria are destroyed by enzymes in tears

Lymphatic System Works closely with the circulatory system As microorganisms are collected in the lymphatic system they are destroyed by specialized white blood cells called lymphocytes Macrophage – WBC that engulfs and digests foreign bacteria Pus – mass of dead WBC and bacteria

Antibody Formation Antibody: protein molecules that inactivate foreign substances by binding to its surface Antigen: the foreign substance that causes disease Each antigen has a specific antibody that will bind to it Our bodies can only create antibodies to disease causing agents that we have previously been exposed to ANIMATION: Immune System Response

immunity An immune response is the production of antibodies to counteract a pathogen Active Immunity body produces antibodies to combat a specific disease  lifelong Can be achieved through vaccines Passive Immunity Antibodies are directly injected in bloodstream Babies acquire immunity through their mothers Babies will eventually need vaccinations to strengthen their immunity

Vaccines vs. antibiotics designed to kill pathogenic bacteria ONLY Doctor will get a sample of the affected area and send it for testing before prescribing antibiotics to make sure it is a bacterial infection Take antibiotics until it is finished to make sure the bacteria is eliminated from the body

Vaccines vs. antibiotics Weakened strain of bacteria or virus that will increase active immunity (create antibodies) Once pathogenic bacteria and virus enters the body, antibodies recognize it, bind to it and macrophages destroy it before it causes damage to our bodies