Neutrophil granulocytes are the most abundant type of white blood cells in mammals and form an essential part of the innate immune system. In general, they are referred to as either neutrophils or polymorphonuclear neutrophils (or PMNs), and are subdivided into segmented neutrophils (or segs) and banded neutrophils (or bands). They form part of the polymorphonuclear cell family (PMNs) together with basophils and eosinophils.