How does the immune system defend the body against pathogens?

[Anonymous]

[richardcory]

The immune system is very complex and has many parts. One particular part is antibodies that combat viruses. Your body makes a huge variety of these that move through your bloodstream. When one encounters a virus and happens to match some feature on that virus, it can disable the virus. Then (though a compex process I don't understand well) it triggers the body to make more antibodies of the same type, and those attack the other viruses of that type. Your immune system "remembers" that design so it can use it again.

Its how vaccinations work - something that looks like the virus is injected. Your bodies antibodies find it (and may make you feel a little sick), and trigger your body into making a lot more. When the real virus shows up your body already knows how to make antibodies to fight it, so it gets a big head start.

There are lots of other parts of the immune system as well, Its incredibly complicated