What white blood cells do

Tiny guards patrol your blood right now, fighting germs!

Your blood is full of cells. Most are red, but a few are white, and they are your defenders. Think of your body as a castle. White blood cells are the guards walking the halls, always on watch.

• White cells among red cells

They are made in your bone marrow, the soft middle of your bones, then travel all around your body.

Germs like bacteria and viruses sneak in through cuts, food, or the air we breathe.

When a germ gets in, white blood cells rush to the spot. This is how the fight begins.

Some white cells simply eat germs. They wrap around the invader and swallow it whole, like a hungry Pac-Man.

Other white cells make antibodies. These are tiny tags that stick to germs and mark them for removal.

• Antibodies = germ tags

Here is the best part. Some white cells remember germs, so next time your body fights faster.

Here is one example. You scrape your knee, and the area turns red, warm, and a bit swollen.

That redness means white cells are crowding in to protect you. A little pus is just dead cells and germs.

• Redness = defenders arriving

This is why doctors count white cells in a blood test. Too many often means your body is fighting something.

You can help your guards by sleeping well, eating fruit and vegetables, and washing your hands.

Quick check. What is the main job of white blood cells? White blood cells are your body's guards: they eat germs, tag them, and remember them for next time.