The Immune System

When we are sick, our bodies respond When we are sick, our bodies respond. Think of a recent time when you were ill. What was wrong? What did you feel like? How did your body react? With this in mind… what do you think the function of the immune system is, and what might happen if it does not work well?

What is it? The body's defense system against germs and other invaders Made up of special cells, proteins, tissues, and organs

Three Lines of Defense First Line Second Line Third 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

First Line 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

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

Third Line Macrophages Lymphocytes Antibodies Lymph Nodes Vaccines

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

Lymphocytes Specialized WBCs that 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

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

Lymph Nodes Trapping stations that help assist in destroying the infection

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