To be immune (say: ih-MYOON) means to be protected. So it makes sense that
the body system that helps fight off sickness is called the immune system. The immune
system is made up of a network of cells, tissues, and organs that work together to
protect the body.
White blood cells, also called leukocytes (say: LOO-kuh-sytes), are part of this
defense system. There are two basic types of these germ-fighting cells:
phagocytes (say: FAH-guh-sytes), which chew up invading germs
lymphocytes (say: LIM-fuh-sytes), which allow the body to remember and recognize
Leukocytes are found in lots of places, including your spleen, an organ in your
belly that filters blood and helps fight infections. Leukocytes also can be found
in bone marrow, which is a thick, spongy jelly inside your bones.
So you have this great system in place. Is it enough to keep you from getting sick?
Well, everyone gets sick sometimes. But your immune system helps you get well again.
And if you've had your shots (also called vaccines),
your body is extra-prepared to fight off serious illnesses that your immune system
alone might not handle very well. If you get the shot that covers measles, for instance,
it can protect you from getting measles, if you're ever exposed to it.
Healthy kids can help their immune systems by washing
their hands regularly to prevent infections, eating nutritious foods, getting
plenty of exercise, getting enough sleep, and getting regular medical checkups. And
if you feel great today, thank your immune system!