1. Lesson Starter Explain how the skin protects the body
What are the secondary methods of protection

2. Cells Alive
Fighting back!

3. Learn about when microbes get into our body
Today we are going to..
Learn about when microbes get into our body

4. The immune system
Sometimes microbes get past our first and second lines of defence and enter our body
Could be through a cut or in food
Our immune system deal with the invading microbes

5. War in our bodies
In the battle against infection the immune system is a bit like sending in the troops . This is now war.

6. Phagocytosis
One of the bodies methods of fighting infection is phagocytosis.
This involves the engulfing (catching) and digestion ( breaking up) of micro-organisms by special cells called phagocytes.
Phagocytes are a type of white blood cell

7. Phagocytosis Stage 2 Stage 1
The microorganism is detected and the phagocyte moves to attack it
Stage 2
The phagocyte engulfs (catches) the microorganism

8. Stage 3 Enzymes (chemicals) in the phagocyte digest the micro-organism
Phagocytosis
Stage 3 Enzymes (chemicals) in the phagocyte digest the micro-organism
Stage 4
The broken down microbes parts can be used by your body.

9. Phagocytosis

10. Draw
In your jotters; draw 4 diagrams to show the stages of PHAGOCYTOSIS
Microorganism detected and phagocytes moves towards it
Phagocyte engulfs microorganism
Enzymes digest microorganism
Microbes broken down and used by body

11. Infection Battle
In the battle against infection the Phagocytes are a bit like foot soldiers on patrol. They are on the ground and looking for any problems or trouble and ready to deal with it

12. Antibodies Antibodies are the MISSILES
Antibodies are produced by white blood cells called lymphocytes
Antibodies are molecules that the body produces to destroy microbes.

13. Antibodies
Antibodies are Y shaped molecules that grab onto microbes

14. Antibodies
Every microbe has a different shape so your body has to make new antibodies for every microbe that infects your body

15. Your body’s memory
Your body keeps a memory of all the antibodies it has made in the past. This means if the same microbe returns you already have the correct antibodies and can produce more very quickly.
This means that the same microbe cannot usually infect you twice which explains why most people only catch a disease once in their life.

16. Think.. Pair.. Share What is it ?
If your immune system can tell the difference between what is yours and not yours then this can cause a problem.
What is it ?

17. Homework research task: Page 29