Ms. Kelly 8 th Grade Health

 The body's defense against germs and other invaders  Made up of special cells, proteins, tissues, and organs

 First Line ◦ Act as barriers to prevent pathogens from entering body  Second Line ◦ Act when tissues are injured or damaged ◦ Signs and symptoms letting you know you are sick  Third Line ◦ Act to destroy and remove pathogens

 Skin  Mucus membranes ◦ Tissues that protect the interior surfaces of the body that may be exposed to pathogens ◦ Secrete MUCUS—a sticky fluid that traps pathogens

 Tears/saliva/sweat ◦ Contain lysozome—an enzyme that breaks down the cell wall of certain pathogens  Fever ◦ Chemicals are released, increasing body temp.  Gastric juices  Pain

 Macrophages  Lymphocytes  Antibodies  Lymph Nodes  Vaccines

 Pac-man like white blood cells (WBCs)  Consume and destroy pathogens

 Specialized WBCs  Activate the immune response  Helper T-cells ◦ Detect the virus and alert the Killer Ts and B-cells  Killer T-cells ◦ Release chemicals to destroy pathogens  B-cells ◦ Make antibodies

 “Lock” into pathogen (antigen) and destroy it  Remain in the blood stream in case the same germ(s) come back  Antibodies at work... Antibodies at work...

 Trapping stations that help assist in destroying the infection

 Small or weakened dose of the pathogen (antibodies), given to activate the immune response