1. ACOS 3
Relate major tissues and organs of the skeletal, circulatory, reproductive, muscular, respiratory, nervous, and digestive systems to their functions.

2. The Immune System is made up of many systems like the lymphatic, integumentary, respiratory, digestive, and circulatory systems in order to fight pathogens.
Pathogens are any and all types of disease-causing organisms.
If your body doesn’t recognize it then it will treat it like a pathogen.

3. The lymphatic system rids the body of excess water and works with the immune system.
Tonsils keep harmful microorganisms from moving past your throat .
Lymphocytes are a type of white blood cell that are made by the thymus and found in lymph.
Lymph nodes filter out microorganisms and foreign materials that have been taken up by lymphocytes.

4. The integumentary system uses the skin as a barrier that prevents many pathogens from entering your body.
As we have said before, your skin is like a bodyguard, it lets the things in that are safe to come in but keeps things out that need to stay out.

5. Your respiratory system traps pathogens with hair-like structures, called cilia, and mucus.
Coughing and sneezing are natural ways of getting rid of pathogens.
Your body is designed to always get rid of pathogens as quickly as possible.

6. Your digestive system has several defenses against pathogens such as enzymes, hydrochloric acid, and mucus.
Hydrochloric acid in your stomach kills many bacteria and stops the activity of some viruses that enter your body on food.

7. The inside of your stomach has a special lining to keep hydrochloric acid inside because if it got out, it would destroy the internal organs it came in contact with.

8. An antibody is a protein made in response to a specific pathogen that attaches to the pathogen and disables it.
When a pathogen invades your body, you immediately start to make antibodies to attack the pathogen.
After you get well some antibodies stay on duty in your blood, and more can be produced rapidly if the pathogen enters your body again.

9. A child who has been around many kids like at a daycare is far less likely to get sick as much when starting school as a child who has stayed home with a parent.

10. The circulatory system contains white blood cells that surround and digest pathogens.

11. If white blood cells cannot destroy pathogens fast enough, you might develop a fever.
A slight increase in body temperature is a natural defense that slows a pathogen’s growth.
Sometimes we actually hinder our own body from doing its job by taking medicine to reduce a low grade fever.

12. Active immunity is when your body makes its own antibodies in response to a pathogen.
Passive immunity is when antibodies that have been produced in another animal are introduced into your body.

13. A vaccine is made from weakened or dead virus particles that can’t cause disease anymore.
A vaccine can only reduce our chances of getting a disease; it cannot cure it.