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Pronunciation: mon'o-sit

Definition: A relatively large mononuclear leukocyte (16–22 mcm in diameter) that normally constitutes 3–7% of the leukocytes of the circulating blood and is normally found in lymph nodes, spleen, bone marrow, and loose connective tissue. When treated with the usual dyes, monocytes manifest an abundant pale blue or blue-gray cytoplasm that contains numerous fine, dustlike, red-blue granules; vacuoles are frequently present; the nucleus is usually indented, or slightly folded, and has a stringy chromatin structure that seems more condensed where the delicate strands are in contact. Monocytes that leave the bloodstream and enter the connective tissue spaces are called macrophages.

[mono- + G. kytos, cell]

See Also: monocytoid cell, endothelial leukocyte

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© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.