Granulocyte

framed|Eosinophil granulocyte
framed|A basophil with lobed nuclei surrounded by erythrocytes

Granulocytes are a category of white blood cells which have granules in their cytoplasm.Hoffbrand A.V. Pettit J.E. and Moss P.A.H. 2005. Essential haematology 4th ed, Blackwell, Oxford.  They are also called polymorphonuclear leukocytes because of the shape of the nucleus, which has three segments. The term polymorphonuclear leukocyte often refers just to neutrophils, the most abundant of the granulocytes.

Granulocytes are released from the bone marrow. They operate by phagocytosis and other means.Ernst J.D. and Stendahl O. (eds) 2006. Phagocytosis of bacteria and bacterial pathogenicity, Cambridge University Press.  Website

Types of granulocytes
There are three types of granulocytes, distinguished by their appearance under Wright's stain:
 Neutrophil granulocytes
 Eosinophil granulocytes
 Basophil granulocytes

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

Other white blood cells which are not granulocytes are mainly lymphocytes and monocytes.

Related pages
 Agranulocytosis (not enough white blood cells in the blood)

 References 

Category:Immunology
Category:Blood cells