1. Immune system

2. Immune System A system that prevents disease and infection
What is our immune system?
A system that prevents disease and infection
The immune system “cleans the body” by removing what?
Pathogens such as bacteria and viruses

3. 1st Line of Defense
Three things that are included in in our first line of defense include:
1. SKIN (acts as a barrier)
2. Mucus/Cilia
Mucus = sticky to trap germs
Cilia = tiny hairs that “sweep” out germs
3. Gastric Juice (acids in stomach kill germs)

4. 2nd Line of Defense 1. Inflammation (phagocytic WBC’s) 2. FEVER
Two things that make up the 2nd line of defense are
1. Inflammation (phagocytic WBC’s)
2. FEVER
When do we need the 2nd line of defense?
When the 1st line fails and pathogens get into the body!!

5. INFLAMMATION 1. What is Inflammation?
an increased blood flow to a part of the body that has been injured or invaded by a pathogen (hot, red, swollen)
2. Why do you think the skin over an infection is hotter than the surrounding skin?
There is more blood at that site so it raises the temperature
3. What line of defense is inflammation?
2nd line

6. 3rd line of defense What is your body’s 3rd line of defense?
Anti-bodies
What are anti-bodies?
Specific proteins that are made by WBCs to fight off pathogens
Where would we find anti-bodies?
Plasma of the blood
What is an antigen?
Anything that can stimulate an immune response

7. Shape What is the most common shape of an anti-body? The “Y” shape
How does the shape of an antibody change from a T to a Y?
When it connects to an antigen
Do you think antibodies are shape-specific? That is, do the antigen and anti-body have to fit together properly for it to work?
YES

8. Lymphocytes-A special type of WBC that makes antibodies
What is another name for WBCs?
Leukocytes
What does the word “phagocytosis” mean?
Cell eating

9. New Invaders What does it mean when we say antibodies are specific?
Their shape has to fit with the antigen they are fighting
Do you think this is a specific defense?
YES!
What happens when a pathogen invades the body?
Anti-bodies are created