Granulocyte

Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm. They are also called polymorphonuclear leukocytes (PMN, PML, or PMNL) because of the varying shapes of the nucleus, which is usually lobed into three segments. This distinguishes them from the mononuclear agranulocytes. In common parlance, the term polymorphonuclear leukocyte often refers specifically to neutrophil granulocytes, the most abundant of the granulocytes; the other types (eosinophils, basophils, and mast cells) have lower numbers. Granulocytes are produced via granulopoiesis in the bone marrow.

Types of granulocytes

There are three principal types of granulocytes, distinguished by their appearance under Wright's stain:

Mnemonic: "BEN"

Their names are derived from their staining characteristics; for example, the most abundant granulocyte is the neutrophil granulocyte, which has neutrally staining cytoplasmic granules.