Leukocyte, granular
A type of white blood cell filled with microscopic granules (tiny sacs) containing enzymes that digest microorganisms. Granular leukocytes — they are better known as granulocytes — are part of the innate immune system and have somewhat non specific, broad-based activity. They do not respond exclusively to specific antigens, as do B-cells and T-cells. Neutrophils, eosinophils and basophils are all types of granulocytes. They are named by the staining features of their granules in the laboratory: Neutrophils have "neutral" subtle granules; Eosinophils have prominent granules that stain readily with the acid dye eosin; and Basophils have prominent granules that stain readily basic (non acidic) dyes. This classification dates back to a time when certain structures could be identified in cells by histochemistry, but the functions of these intracellular structures were still not yet fathomed. However, the classification of granulocytes into neutrophils, eosinophils and basophils is still widely used (and quite useful).

Medical dictionary. 2011.

Look at other dictionaries:

  • leukocyte — [lo͞o′kō sīt΄, lo͞o′kəsīt΄] n. [see LEUCO & CYTE] any of the small, colorless nucleated cells in the blood, lymph, and tissues, which are important in the body s defenses against infection, including granular types such as neutrophils,… …   English World dictionary

  • Granular leukocyte — A type of white blood cell filled with microscopic granules (tiny sacs) containing enzymes that digest microorganisms. Granular leukocytes they are better known as granulocytes are part of the innate immune system and have somewhat non specific,… …   Medical dictionary

  • leukocyte — 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 (rarely in other tissues). Under various… …   Medical dictionary

  • granular leukocyte — noun : a blood granulocyte; especially : a polymorphonuclear leukocyte …   Useful english dictionary

  • leukocyte — (loo ko saīt) Any colorless white blood cell. Can be classified into granular and agranular lymphocytes …   Dictionary of microbiology

  • nongranular leukocyte — n any of the white blood cells that usu. lack granules in their cytoplasm having an affinity for specific biological stains and that include the lymphocytes and monocytes called also monouclear leukocyte compare GRANULAR LEUKOCYTE * * * a… …   Medical dictionary

  • Polymorphonuclear leukocyte — A type of white blood cell with a nucleus that is so deeply lobated or divided that the cell looks to have multiple nuclei. Informally called a poly. * * * any fully developed granular leukocyte whose nucleus contains multiple lobes joined by… …   Medical dictionary

  • Cell — The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane. Each cell in the human body there are 100 trillion cells in each of us contains the entire… …   Medical dictionary

  • cluster of differentiation — Cell membrane molecules that are used to classify leukocytes into subsets. CD molecules are classified by monoclonal antibodies. There are four general types: type I transmembrane proteins have their COOH termini in the cytoplasm and their NH2… …   Medical dictionary

  • blood — bloodlike, adj. /blud/, n. 1. the fluid that circulates in the principal vascular system of human beings and other vertebrates, in humans consisting of plasma in which the red blood cells, white blood cells, and platelets are suspended. 2. the… …   Universalium

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”