- Blood cells: These develop from stem cells and are formed in the bone marrow. There are three types: red and white blood cells and platelets.
- White blood cells: These fight infection and disease and there are several types, including neutrophils and lymphocytes, which all play different roles in helping your body fight infections.
- Red blood cells: Carry oxygen around the body in the bloodstream.
- Platelets: These help your blood to clot.