Lesson 24:

The Human Body's

Defence System


Uh oh! Someone in the line at the cafeteria just sneezed! And does anyone ever clean the keyboards in the computer lab? What if there is a virus hanging around? There are many opportunities every day for you to be exposed to diseases. Why don’t you become ill more often? The answer is that your body has many lines of defence against disease. In this lesson, you will learn about the ways your body can protect itself from invaders and you will also learn about treatments that are available for when you do get sick.


 
 

 

 

In this lesson, you will:

  • learn about some of the features of your body that protect it from infection and disease
  • learn about how the body works to fight diseases that get past the external barriers
  • learn about the ways vaccines and antibiotics assist human disease defences
     



Key terms for this lesson:

  • active immunity
  • antibiotic
  • antigens
  • immune response
  • immunity
  • mucous membranes
  • passive immunity
  • pathogens
  • vaccine
  • white blood cells