1. Mrs. Vogel 7th Grade Teen Living
The Immune System
Mrs. Vogel
7th Grade Teen Living

2. Nothing to fear because your body protects you
Keeping Pathogens Out
Pathogens are in the air you breathe, the water you drink, and on every surface you touch.
You can get a pathogen on your skin by coming into contact with a person who has an infection.
You can catch them from insects too
Nothing to fear because your body protects you

3. Keeping Pathogens Out
Your body can block, trap or break down most pathogens before they make you sick
Your body has 5 major barriers to block pathogens
Tears
Saliva
Skin
Mucous membranes
Stomach acid

4. Keeping pathogens out
These barriers are your body’s first line of defense
If the pathogens get past the barriers the body’s immune system gets to work

5. Immune System
Immune System- a combination of body defenses made up of cells, tissues, and organs that fight pathogens in the body
The Immune System has two responses:
Nonspecific response
Specific Response

6. Nonspecific Response
Example: When you get a splinter in your finger along with dirt and other pathogens that are on the splinter these pathogens go into the body.
Your body responds with a nonspecific immune response.
This is called nonspecific = it is the same no matter what foreign matter enters the body

7. Nonspecific Response Splinter Example continue…
The skin around the splinter soon becomes swollen and red. This is known as inflammation
Inflammation- the body’s response to injury or disease, resulting in a condition of swelling, pain, heat, and redness

8. Nonspecific Response
Why does the area around the Splinter become inflamed?
After the splinter breaks the skin, circulation around the area slows down. Fluids trapped in the area leak into the surrounding tissues. The White Blood Cells surround the pathogen (splinter) and destroys them

9. Nonspecific Response Your body has many other nonspecific responses
Example: When you have an infection, your body produces more protein to boost the immune system to help stop the viruses from multiplying
Example: When your body temperature rises, it’s harder for the pathogens to reproduce

10. Specific Response
When the pathogens get past the Nonspecific response the second response takes action, Specific Response
Each specific response attacks a particular pathogen
Your Immune System can recognize pathogens it has dealt with before

11. Specific Response
Once your immune system has created a specific response, those response cells remain in your body.
If that same pathogen comes back the cells recognize it and fight it right away

12. The Lymphatic System
Lymphatic System- a secondary circulatory system that helps the body fight pathogens and maintains its fluid balance.
The fluid circulating in the lymphatic system is called lymph
Macrohphages are found in the lymph and they destroy foreign substances in the body

13. The Lymphatic System
After the macrphages destroy the foreign substance they help the lymphocytes identify it.
Lymphocytes- are special white blood cells in the blood and lymphatic system

14. Three Main Kinds of Lymphocytes
B Cells
T Cells
NK Cells (Natural Killer) This cell attacks cancers and viruses
All three cells are activated when the body recognizes a part of a pathogen known as an antigen.

15. Antigens and Antibodies
Antigen- are substances that send the immune system into action.
Example- substances on the surface of a bacterium
Your body reacts by making more B cells and T cells. Some B cells make Antibodies
Antibodies- specific proteins that attach to antigens, keeping from harming the body

16. Antigens and Antibodies
Some of the new B cells and T cells do not react the to the first encounter with a pathogen
They wait to react if the same kind of pathogen invades the body again= memory B cells and Memory T cells

17. Immunity
Immunity- the ability to resist the pathogens that causes a particular disease.
Your body builds immunity to certain diseases. As the memory cells remember the antigen so it can fight it
Vaccine- a preparation of dead or weakened pathogens that is introduced into the body to cause an immune response.
This process is called Immunization