Red / White blood cells & Platelets

Platelets always circulate in our bloodstream, looking for tiny tears in blood vessels where blood might leak out, like a paper cut. They accumulate in such cuts during clotting. Red blood cells carry fresh oxygen from the lungs to all the cells that need it, and then carry away the unneeded carbon dioxide. White blood cells are immune responders that combat foreign microorganisms. Those invaders might cause infection, so white blood cells help produce antibodies that keep the invaders from causing damage.