Bone marrow is the spongy tissue that is located inside the long bones.
The blood cells and platelets are produced within the bone marrow. The cells have a vital role in keeping the body healthy and free of disease. The red blood cells pick up and carry oxygen from the lungs and distribute this oxygen to the rest of the body. White blood cells fight invading infections. Platelets allow the blood to clot, for example, after injury from a cut or scrape.