1. What keeps us from getting sick?
Our immune system is the body system that protects the body from infection and disease.
Vocabulary:
Antibody
Antigen
Immune system
Pathogen
White blood cells
(c) McGraw Hill Ryerson 2007

2. The Immune System Infectious diseases are caused by pathogens.
A pathogen is a microorganism that invades the body and cause disease.
Eg. Salmonella can cause food poisoning
When a pathogen enters the body, it causes an immune response.
The immune response is the immune system mounting an attack to destroy these disease-causing invaders.
See pages
(c) McGraw Hill Ryerson 2007

3. How do pathogens enter our bodies?
1. Direct Contact (through breaks in the skin)
Pathogens can enter the body from body fluids such as saliva, blood and semen, through cuts and scratches, and through needle punctures.
Kissing, touching, sexual intercourse
Eg. Sexually transmitted diseases, hepatitis, and HIV/AIDS are often spread by this route.
(c) McGraw Hill Ryerson 2007

4. How do pathogens enter the body?
2. Indirect contact (Inhalation)
When you cough or sneeze, tiny droplets fly out of your mouth and nose. If you have an infection, those droplets will contain microorganisms.
Other people can breathe in the droplets, along with the viruses and bacteria they contain.
The common cold and tuberculosis are spread in this way
 COUGH INTO YOUR SLEEVE!
(c) McGraw Hill Ryerson 2007

5. How do pathogens enter our bodies?
3. By Ingestion (through the mouth)
Consuming food or water contaminated with bacteria or viruses
Improperly cooked food may contain Salmonella  or  E. coli.
Water needs to be purified by filtering, chemicals, or boiling.
(c) McGraw Hill Ryerson 2007

6. How do pathogens enter the body?
4. By vectors (usually through the skin or by ingestion)
A vector is an organism that doesn’t cause disease but spreads it from one host to another without suffering any harm itself.
Vectors include mosquitoes (malaria and Zika virus) and houseflies (dysentery).
Bites from an animal with rabies virus.
(c) McGraw Hill Ryerson 2007

7. Ted ed germ theory https://www.youtube.com/watch?v=N9LC-3ZKiok
How are germs spread?
The Sneeze
Ted ed germ theory
 Ted ed How germs spread
(c) McGraw Hill Ryerson 2007

8. Activity: Pass it on.
Spread your germs
(c) McGraw Hill Ryerson 2007