1. The Body’s Defenses
Explain how the body’s first line of defense guards against pathogens
Describe what happens during the inflammatory response
State how the immune system responds to pathogens

2. The Body’s Defenses
Our bodies have an army of soldiers for protection from invaders
All of them work together, forming the immune system

3. Barriers
In the first line of defense, the surfaces of the skin, breathing passages, mouth, and stomach function as barriers to pathogens
These barriers trap and kill most pathogens with which you come into contact

4. Barriers
Skin
Pathogens land on skin and are exposed to destructive chemicals (oil and sweat)
Pathogens may also fall off with dead skin cells
Then they must get through tightly packed dead cells that form a barrier over live cells
Most enter through cuts in the skin

5. Barriers Breathing passages
Nose, pharynx, trachea, and bronchi contain mucus and cilia
The mucus and cilia trap and remove most of the pathogens that enter
Pathogens may irritate as they enter making you sneeze or cough kicking the pathogens out

6. Barriers Mouth and Stomach Some pathogens are in foods
The saliva in the mouth contains chemical may kill
The stomach produces acid which can kill pathogens

7. The Inflammatory Response
When body cells are damaged, they release chemicals that trigger the inflammatory response
This is our 2nd line of defense

8. The Inflammatory Response
In the inflammatory response, fluid and white blood cells leak from blood vessels into nearby tissues
The white blood cells then fight the pathogens

9. The Inflammatory Response
White blood cells
All are disease fighters
Phagocytes- type of WBCs that are involved in the inflammatory response
Engulfs pathogens and destroys them

10. The Inflammatory Response
Inflammation
Blood vessels widen in the area affected by the pathogens. This enlargement increases blood flow to the area causing more disease fighters to go to the scene
The enlarged blood vessels makes the area red and swollen. If you touch the swollen area, it will fell warmer than usual

11. The Inflammatory Response
Fever
Chemicals in the response cause a fever
It helps our body fight infection
Some pathogens do not grow and reproduce well at higher temperatures

12. The Immune System
Immune response- if pathogen infection causes fever, it triggers the 3rd line of defense – immune response
The cells of the immune system can distinguish between different kinds of pathogens. The immune system cells react to each kind of pathogen with a defense targeted specifically at that pathogen

13. The Immune System Lymphocytes
White blood cells that distinguish between different kinds of pathogens
Two major types
B cells
T cells

14. The Immune System Lymphocytes
T cell- functions to identify pathogens and distinguish one kind of pathogen from another
We have 10’s of millions of T cells
T cells recognize antigens (molecules that the immune system recognizes as foreign)

15. The Immune System Lymphocytes B cells
Produce proteins that help destroy pathogens
These proteins are antibodies
Each kind of B cell produces only one kind of antibody, and each antibody has a different structure

16. The Immune System Lymphocytes B cells
Antigens and antibodies fit together like puzzles
Antibodies bind to antigens so that they will be recognized and destoryed

17. The Immune System
AIDS- disease caused by a virus that attacks the immune system
Virus= HIV

18. The Immune System
AIDS
HIV is the only kind of virus known to attack the human immune system directly and destroy T cells
HIV destroys T cells and the body loses its ability to fight disease

19. The Immune System AIDS- how it’s spread It can only reproduce in cells
HIV can spread from one person to another only if body fluids from an infected person come in contact with those of an uninfected person
Sexual contact, Pregnancy, Infected blood

20. Assignment: IS Analogy
Your body is its own nation. You have recently been invaded. Explain your war strategy against the enemy. You will have three battles, describe your defenses for each.