The Immune SystemCENTERVILLE

8th Grade Health

Journal:

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?

The body's defense against germs and other invaders

Made up of special cells, proteins, tissues, and organs

What is it?

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

Three Lines of Defense

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

First Line

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

Second Line

Macrophages Lymphocytes Antibodies Lymph Nodes Vaccines

Third Line

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

Macrophages

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

Lymphocytes

“Lock” into pathogen (antigen) and destroy it

Remain in the blood stream Antibodies at work...

Antibodies

Trapping stations to destroy infection

Lymph Nodes

Small or weakened dose of the pathogen (antibodies)

Vaccine