Bone marrow cells,coloured transmission electron micrograph (TEM). Section through bone marrow cells,showing a mature red blood cell (erythrocyte,pink oval,centre),immature red blood cells (reticulocytes,pink spotted),and white blood cells (leucocytes,blue and grey). Two types of leucocytes are visible: neutrophils have multi-lobed nuclei (dark blue patches),while myelocytes have large nuclei that take up most of the cell. Bone marrow occupies the hollow interior of bones,and is the site of new blood cell production. Magnification: x2500 when printed 10 centimetres tall |