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− | [[Image:Monocyte.jpg|150px|thumb|right|'''Monocyte''' (Copyright © RVC. All rights reserved)]] | + | [[Image:LH Monocyte Histology.jpg|right|thumb|150px|<p>'''Monocyte'''</p><sup>©RVC 2008</sup>]] |
| + | <p>Monocytes are the largest [[Leukocytes - WikiBlood|leukocytes]]. They have a large indented nucleus, few granules and constitute about 5% of circulating [[Leukocytes - WikiBlood|leukocytes]]. Monocytes are precursors to a number of cells that make up the [[Lymphoreticular System - Anatomy & Physiology|mononuclear phagocytic system]]. Developing in the [[Bone Marrow - Anatomy & Physiology|bone marrow]], monocytes migrate into the circulation where, after approximately three days, they migrate into tissues and differentiate.</p> |
| + | ==Development== |
| + | <p>Monocytes develop from the bi-potential [[Overview of Haematopoiesis - WikiBlood#Colony Forming Units|CFU-GM]] stem cell. Further details of this process ([[Leukopoiesis - WikiBlood|leukopoiesis]]) can be found [[Leukopoiesis - WikiBlood#Monocyte development|here]].</p> |
| + | <p>When monocytes leave the blood stream they then differentiate into a number of cells (all are [[Macrophages|macrophages]]): |
| + | * Connective tissue histiocyte |
| + | * [[Respiratory System General Introduction - Pathology#Alveolar macrophages|Alveolar macrophage]] |
| + | * Peritoneal macrophage |
| + | * Kupffer cell of [[Liver - Anatomy & Physiology|liver]] |
| + | * Melanophage of skin |
| + | * Lipophage |
| + | * [[Bones - Anatomy & Physiology#Osteoclasts|Osteoclasts]] in bone |
| + | * Microglial cell in bone & brain |
| + | * Specialised histiocytes |
| + | ** Epithelioid cell |
| + | * Histiocytic giant cell |
| + | ** Langhan’s cell |
| + | ** Foreign body |
| + | ** Touton</p> |
| + | [[Image:Monocyte Picture.jpg|thumb|right|150px|Monocyte Picture - Copyright Prof Dirk Werling DrMedVet PhD MRCVS]] |
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− | Monocytes are generally the largest [[Leucocytes|leucocyte]] and have a nucleus that is ovoid and indented (often bean shaped). The cytoplasm usually stain blue-gray and often is vacuolated. The monocytes range is generally between 0 and 10% of the differential and may increase in chronic infections.
| + | ==Action== |
| + | <p>During inflammation chemokines attract monocytes which migrate out of blood vessels into the damaged tissue, where they differentiate into cells of the [[Lymphoreticular System - Anatomy & Physiology|mononuclear phagocytic system]].</p> |
| + | <p>Monocytes can live for months to years in the circulation.</p> |
| + | <p>Monocytes are referred to as macrophages once they enter a tissue by '''diapedesis'''.</p> |
| + | <p>Monocytes/macrophages act as phagocytes, removing particular antigens. They also act as antigen presenting cells to take up, process and present antigen to [[Lymphocytes#T cells|T cells]].</p> |
| + | ===In pathology=== |
| + | *[[Changes in Inflammatory Cells Circulating in Blood - Pathology#Monocytosis|Monocytosis]] |
| + | <br> |
| + | ---- |
| + | <center><b><sup>Blood cells: [[Erythrocytes - WikiBlood|Erythrocytes]] | |
| + | [[Basophils - WikiBlood|Basophils]], [[Eosinophils - WikiBlood|Eosinophils]], [[Lymphocytes|Lymphocytes]], [[Macrophages|Macrophages]], [[Mast Cells - WikiBlood|Mast cells]], [[Monocytes - WikiBlood|Monocytes]] & [[Neutrophils|Neutrophils]] | [[Thrombocytes|Thrombocytes]] & [[Thrombopoiesis - WikiBlood#Megakaryocyte|Megakaryocytes]]</sup></b></center> |
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− | [[Category:Lizard_and_Snake_Glossary]] | + | |
| + | [[Category:WikiBlood]] |