Nucleated red blood cell Nucleated red blood cell All vertebrate organisms have hemoglobin-containing cells in their blood and with the exception of mammals, all of these red blood cells contain a nucleus. Mammals represent ~5,500 named species out of ~66,000 vertebrate species, and within this ~8% subgroup, red blood cells are known as erythrocytes or RBCs and lack a cell nucleus in mature organisms. In contrast, a nucleated red blood cell (NRBC), also known by several other names, is a mammalian RBC that contains a cell nucleus. NRBCs occur in normal development as progenitor cells in the erythropoietic lineage and in pathological states. Normally,
Blood cell in the human body in that they lack a nucleus (although erythroblasts do have a nucleus). The condition of having too few red blood cells is known as anemia, while having too many is polycythemia. White blood cells or "leukocytes", are cells of the immune system involved in defending the body against both infectious disease and foreign materials. They are produced and derived from multipotent cells in the bone marrow known as a hematopoietic stem cells. Leukocytes are found throughout the body, including the blood and lymphatic system. There are a variety of types of white bloods cells that serve