1. The Immune System

2. The Job of the Immune System
The immune system protects our bodies from a variety of pathogens (organisms that cause diseases).

3. Types of Pathogens *Virus-ultramicroscopic infectious agent that replicates itself only within cells of living hosts.

4. *Carcinogens- any substance that produces cancer.

5. *Pollution- undesirable state of the natural environment being contaminated with harmful substances as a consequence of human activities .

6. *Germs- microbe: a minute life form (especially a disease-causing bacterium)

7. *Toxins-
is a poisonous substance produced by living cells or organisms.

8. *Fungi- including yeast, molds, smuts, mushrooms, and toadstools; distinct from the green plants.

9. *Bacteria- single-celled or noncellular spherical or spiral or rod-shaped organisms lacking chlorophyll.

10. *Parasites- an animal or plant that lives in or on a host (another animal or plant); it obtains nourishment from the host without benefiting or killing the host.

11. How Diseases are Spread
*Person to person -Direct physical contact (kissing, hugging, shaking hands). -Indirect contact such as sneezing and coughing.
*Contaminated Objects
-Water and food
-Using towels and silverware
-Contaminated nail
*Animal Bites
-Animals biting a person can transfer the pathogen.
*The environment
-Naturally occurring in soil and water.

12. How does the body defend itself?
Barriers -Breathing passages
Skin
Mouth and stomach