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Innate Immunity Cellular Responses (view source)

Revision as of 10:06, 1 May 2012

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→‎Macrophages

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==[[Macrophages|Macrophages]]==

[[Image:Monocytes.jpg|thumb|right|150px|Monocytes - J. Bredl, RVC 2008]]

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*The ~~role of~~ macrophages in ~~Innate Immunity is to act as primary '''phagocytes'''~~

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The innate cellular response begins with recognition and phagocytosis by macrophages that precide in the tissue where the wound occurs. The populations of distinct, tissue-specific macrophages that are present are the:

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* Macrophages are present within tissues and take the ~~form~~ of distinct, tissue-specific ~~populations~~:

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* Alveolar macrophages (lung)

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** Alveolar macrophages

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* Tissue histiocytes

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** Tissue histiocytes

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* Glomerular macrophages (kidney)

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** Glomerular macrophages

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* Hepatic Küpffer cells (liver)

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** Hepatic Küpffer cells

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* CNS microglia (Central Nervous System: Brain and Spinal Cord)

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** CNS microglia

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* Sinus-lining macrophages of the lymph nodes and spleen

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** Sinus-lining macrophages of the lymph nodes and spleen

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* [[Monocytes|'''Monocytes''']] (immature macrophages) are circulating phagocytes

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** Circulate for 6-8 hours

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When [[Phagocytosis|phagocytosis]] of the bacteria or fungi by the tissue macrophages occurs they release a number of [[Cytokines|cytokines]] that have a number of effects. The first being the activation of the endothelium that results in the expression of adhesion molecules that allow leukocytes, in particular the [[Neutrophils|neutrophils]] to bind to the endothelium from the bloodstream and the subsequent extravasation (movement out of the bloodstream). Once the leukocytes are out of the bloodstream, the cytokines released by the tissue macrophages act as chemoattractants that enable the chemotaxis of the leukocytes to the site of infection.

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** Can function as phagocytes within the blood and as newly migrated cells in tissues

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** Chiefly function to replace the various tissue macrophage populations

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The [[Monocytes|'''Monocytes''']] are immature macrophages that are circulating phagocytes. They circulate for 6-8 hours and function as phagocytes within the blood and as newly migrated cells in tissues. Their primary function, however, is function to replace the various tissue macrophage populations at the latter stages of the immune response.

==[[Neutrophils|Neutrophils]]==

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