1. Immune System

2. What are germs?
How are germs spread?
Are all germs harmful?
How can we reduce the germs we have on us?
How quickly can germs spread?
When you sneeze how fast your germs are moving? (80 MP/H)

3. What keeps us from getting sick?
Our immune system is the body system that protects us from infection and disease.

4. Ted Ed: Germ Theory

5. (c) McGraw Hill Ryerson 2007
The Immune System
Infectious diseases are caused by pathogens.
A pathogen is a microorganism that invades the body and causes disease.
Eg. Salmonella causes 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 the disease- causing invaders.
See pages
(c) McGraw Hill Ryerson 2007

6. How do pathogens enter our bodies?
How are germs spread?

7. 1. Direct Contact (through breaks in the skin)
Pathogens in contaminated body fluids such as saliva, blood and semen, can enter the body through cuts and scratches, and needle punctures.
Eg. Kissing, touching, sexual intercourse
Sexually transmitted diseases, hepatitis, and HIV/AIDS

8. How not to get sick: Don’t share body fluids!
Don’t rub your face (especially your eyes) after shaking hands with a sick person.
Don’t have unprotected sexual intercourse
Don’t inject anything unless prescribed by a doctor
Keep wounds covered

10. 2. Indirect contact (Inhalation)
Eg. the common cold and tuberculosis are spread in this way
COUGH INTO YOUR SLEEVE!
Stay home when you are sick
(c) McGraw Hill Ryerson 2007

11. 3. By Ingestion (through the mouth)
Consuming food or water contaminated with bacteria or viruses
Improperly cooked food may contain Salmonella  or  E. coli.

12. How not to get sick
Wash hands, cutting board, utensils after cutting raw meat.
Wash your hands well after using the washroom
Cook your food well, drink only water that is purified by filtering, chemicals, or boiling.

13. 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.
Eg. mosquitoes (malaria and Zika) and houseflies (dysentery).
Bites from an animal with rabies virus.
Dysentery is an inflammatory disease of the intestine, especially of the colon, which always results in severe diarrhea and abdominal pains.
 shivering and chills, followed by a high fever, followed by sweating and a return to normal temperature. Malaria signs and symptoms typically begin within a few weeks after being bitten by an infected mosquito.
(c) McGraw Hill Ryerson 2007

14. Zika

15. Rabies

16. Discussion
Where are some of the places in your school that may have the most germs?
What other common places may have a lot of germs?
What is the most common way to be infected with germs?
Are you more likely to catch them from another person who is already infected?
What are some common diseases/germs we can catch from other people?

17. (c) McGraw Hill Ryerson 2007
How are germs spread?
The Sneeze
(c) McGraw Hill Ryerson 2007

18. (c) McGraw Hill Ryerson 2007
Practice
Handwashing Activity
Spread your germs
HW: How germs are spread WS
(c) McGraw Hill Ryerson 2007