How does your body defend itself against microbes?
Today we are learning:
• About the natural barriers we have to fight infection
• That we make antibodies and specialised cells in the blood to fight microbes
Keywords:
Hygiene, immunity, vaccination, antibodies.
Starter:
Complete your wordsearch of keywords
Extension:
What happens to your body when you catch a cold?
Discuss in pairs.

Many years ago there was a disease called SMALLPOX, people living in the countryside noticed that milkmaids never seemed to catch the deadly disease.
This was because they were subjected to another similar infection caught from the cows they milked (cowpox).

In 1796 a doctor called
Edward Jenner carried out a famous experiment on an eight year old boy called
James Phipps.

Jenner took pus from someone with mild cowpox and put it into a cut in the eight year olds arm.
He never caught smallpox, for many years after that
Jenner conducted lots of experiments to prove that our bodies can become
IMMUNE.

Our bodies have many defence mechanisms against invading microbes:
The skin acts as a barrier
Tears contain an enzyme that kills bacteria
Stomach produces stomach acid
If our skin is cut platelets seal the wound by clotting
The breathing organs produce mucus to cover the lining of these organs and trap the microbes

Ear wax traps them
On your outline of the human body, label how we stop microorganisms getting into our bodies.
Here is an example for you.

We are going to look at how we can kill bacterial.
We need to grow some bacteria to look at next lesson.
Listen carefully to your instructions and make sure you wear goggles!

Turn to the back of your book and put 1 to 10 in the margin.
The questions will pop up, answer them as quickly as possible.

3.
4.
2.
1. Name the 3 main types of microbes
Which organ uses acid to kill microbes?
What do white blood cells make to fight microbes?
Name the doctor that experimented with smallpox
5.
What does engulf mean?
5 correct LEVEL 5
4 correct LEVEL 4
2-3 correct LEVEL 3
0-1 correct LEVEL 2