leucocyte

leu·ko·cyte

(lū'kō-sīt)

A type of cell formed in the myelopoietic, lymphoid, and reticular portions of the reticuloendothelial system in various parts of the body, and normally present in those sites and in the circulating blood. Under various abnormal conditions, the total number of leukocytes may be increased or decreased or their relative proportions altered, and they may appear in other tissues and organs. Leukocytes represent three lines of development from primitive elements: myeloid, lymphoid, and monocytic series. On the basis of features observed with various methods of staining with polychromatic dyes, cells of the myeloid series are frequently termed granular leukocytes, or granulocytes; because the cytoplasmic granules of lymphocytes and monocytes are smaller and frequently not clearly visualized with routine methods, these cells are sometimes termed nongranular or agranular leukocytes. Granulocytes are commonly known as polymorphonuclear leukocytes (also polynuclear or multinuclear leukocytes), because in a mature cell the nucleus is divided into two to five rounded or ovoid lobes that are connected with thin strands or small bands of chromatin; they consist of three distinct types: neutrophils, eosinophils, and basophils, named on the basis of the staining reactions of the cytoplasmic granules. Cells of the lymphocytic series are smaller than other leukocytes and have relatively large, darkly staining, eccentrically placed nuclei. Cells of the monocytic series are usually larger than the other leukocytes and are characterized by a relatively abundant, slightly opaque, pale blue or blue-gray cytoplasm that contains many fine reddish-blue granules. Monocytes are usually indented, reniform, or shaped similarly to a horseshoe, but are sometimes rounded or ovoid; their nuclei are usually large and centrally placed and, even when eccentrically located, are completely surrounded by at least a small band of cytoplasm.
Synonym(s): white blood cell, leucocyte.

[leuko- + G. kytos, cell]

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

leucocyte

Any kind of white blood cell. The leukocytes include the neutrophil POLYMORPHONUCLEAR LEUKOCYTES (‘Polymorphs’), EOSINOPHILS, BASOPHILS, LYMPHOCYTES and MACROPHAGES.

Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

leu·ko·cyte

(lū'kō-sīt)

Cell formed in myelopoietic, lymphoid, and reticular portions of the reticuloendothelial system in various parts of the body, and normally present in those sites and in the circulating blood.
Synonym(s): white blood cell, leucocyte.

[leuko- + G. kytos, cell]

Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about leucocyte

Q. can i get a short explanation about white blood cells and their job? what does it mean if i have a insafition

A. White blood cells (WBC's) are the ones responsible for the immune system in the body. The white blood cell count rises in cases of infection, steroid use and other conditions. A low white blood cell count can have many causes, which need to be further evaluated by a doctor.

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