The Immune The Immune SystemSystem

Protecting the BodyProtecting the Body

First Line of DefenceFirst Line of Defence

The skin keeps The skin keeps out bacteria and out bacteria and virusesviruses

Acidic oils and Acidic oils and sweat prevent sweat prevent micro-organisms micro-organisms from growing on from growing on the skinthe skin

Eyes: have tears with a Eyes: have tears with a special chemical to kill special chemical to kill bacteriabacteria

Ears: have wax to trap Ears: have wax to trap foreign materialforeign material

Mouth and Nose: have Mouth and Nose: have mucus to trap micro-mucus to trap micro-organisms organisms

Cilia in the trachea Cilia in the trachea move the mucus with move the mucus with the invaders outthe invaders out

Second Line of DefenceSecond Line of Defence The circulatory The circulatory

systemsystem White blood cells White blood cells

attack and destroy attack and destroy invaders in the invaders in the blood streamblood stream

Video of white blood cell attacking a bacterium

Third Line of DefenceThird Line of Defence

The immune systemThe immune system All invaders have All invaders have

markers called markers called antigens on their antigens on their surfacessurfaces

Special white blood Special white blood cells make antibodies cells make antibodies to attack themto attack them

Each type of antibody Each type of antibody only recognizes one only recognizes one type of antigentype of antigen

Immune ResponseImmune Response

This is when This is when antibodies are used antibodies are used to fight pathogensto fight pathogens

The body can The body can produce its own produce its own antibodies or they antibodies or they can be induced can be induced through vaccinations through vaccinations to help fight against to help fight against future attack by the future attack by the same pathogensame pathogen