Macrophages
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The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Macrophages from different sites have distinctly different properties. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPPFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.) |
| Notes: |
macrophage migration test: index under MACROPHAGES /immunol (IM) + CELL MIGRATION INHIBITION (IM) |
Macrophages Categories.
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Epithelioid Cells - Characteristic cells of granulomatous hypersensitivity. They appear as large, flattened cells with increased endoplasmic reticulum. They are believed to be activated macrophages that have differentiated as a result of prolonged antigenic stimulation. Further differentiation or fusion of epithelioid cells is thought to produce multinucleated giant cells (GIANT CELLS). |
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Foam Cells - Lipid-laden macrophages originating from monocytes or from smooth muscle cells. |
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Giant Cells, Foreign-Body - Multinucleated cells (fused macrophages), characteristic of granulomatous inflammation, which form around exogenous material in the skin. They are similar in appearance to Langhans giant cells (GIANT CELLS, LANGHANS), but foreign-body giant cells have more abundant chromatin and their nuclei are scattered in an irregular pattern in the cytoplasm. |
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Giant Cells, Langhans - Multinucleated cells (fused macrophages) seen in granulomatous inflammations such as tuberculosis, syphilis, sarcoidosis, and deep fungal infections. They resemble foreign-body giant cells (GIANT CELLS, FOREIGN BODY) but Langhans giant cells contain less chromatin and their nuclei are arranged peripherally in a horseshoe-shaped pattern. Langhans giant cells occur frequently in delayed hypersensitivity. |
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Histiocytes |
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Kupffer Cells - Specialized phagocytic cells of the RETICULOENDOTHELIAL SYSTEM found on the luminal surface of the hepatic sinusoids. They filter bacteria and small foreign proteins out of the blood, and dispose of worn out red blood cells. |
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Macrophages, Alveolar - Round, granular, mononuclear phagocytes found in the alveoli of the lungs. They ingest small inhaled particles resulting in degradation and presentation of the antigen to immunocompetent cells. |
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Macrophages, Peritoneal - Mononuclear phagocytes derived from bone marrow precursors but resident in the peritoneum. |
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Osteoclasts - A large multinuclear cell associated with the BONE RESORPTION. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in CEMENTUM resorption. |
Macrophages Definitions and Terms
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