There are four components - or parts - of the blood: red blood cells, white blood cells, plasma and platelets. Blood carries things you need, like oxygen and glucose, and waste products ...

Some cells do repairs if you get a cut. Red blood cells deliver oxygen and take away rubbish. And your white blood cells are like police looking for germs. There's a lot going on inside you!

Since neither red blood cells nor platelets have nuclei, these patterns largely reflect gene expression in the various types of white blood cells. “But depending on which cells you have more of in ...