The second and third line of defence'

1
The second and third line of defence.
2
Some still get through!

• The body has many barriers to stop microbes
  getting in.
• But sometimes they do get past this first line of
  defence.
• Once inside the microbes have to be destroyed
• The white blood cells do this

3
White blood cells

• There are two types of white blood cell that
  destroy microbes.
• Phagocytes these cells travel round the body
  and ingest (eat) the pathogens
• The pathogens are also called antigens.

4
Lymphocytes

• Lymphocytes these cells can recognise what type
  of pathogen is invading the body.
• They can make special chemicals called
  antibodies which stick to the antigen.
• When the antigens are stuck together the
  phagocytes can ingest and destroy them.

5
Inflammation

• Sometimes an infected cut will fill up with
  yellow pus
• This contains white blood cells and the remains
  of the microbes.
• These areas may become hot and red because extra
  blood is carried to the infection
• This is called inflammation.
• It helps to clear the infection

6
Now try this exercise

• Exercise 6 - Cloze

7
Now try these games to help you remember

• Game 1 Walk the plank
• Game 2 Fling the teacher
• Game 3 Penalty shoot out
• Game 4 Grade or no grade
• Game 5 Half a min