blood is the transport system in your body you need it to keep moving and keep you functioning - your body has about four litre of blood (that's just like 2x 2litre bottles of milk) so we need to becare with our blood as we only have enough just for ourselves.

The red cells in our blood are to carry oxygen and the white cells are to help us fight infections.  The cell parts are called platelets - my Dad has a rare blood function and he does not have that many platelets so it means that if they get to low and he cuts himself it is hard for him to stop bleeding - cause platelets help to stop bleeding and clot