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| ==Lymph Nodes==
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| ===Lymph Node Anatomy===
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| {|
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| ! Lymph Node Anatomy
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| |-
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| | valign=top|
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| * Location throughout the entire body - concentrated in axilla, groin, lung, gastrointestinal tract mesenteries
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| * Small (1 mm - 2 cm) encapsulated organ (diffuse lymphoid tissue - no capsule)
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| * Antigen transformed lymphocytes from the blood
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| * In lymph vessel pathways “filter” lymph
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| ** '''Afferent''' - towards node (A - arrives at the node)
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| ** '''Efferent''' - away from node (E - exits the node)
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| [[File:Gastrointestinal tract intestine immune cartoon 01.jpg|300px]]
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| Mesenteric lymph nodes
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| | [[File:Lymphatic-system-overview.jpg|600px]]
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| |-
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| |}
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| ===Lymph Node Functions===
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| {| class="wikitable mw-collapsible mw-collapsed"
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| ! colspan=2|Lymph Node Functions
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| | valign=top|
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| * In lymph vessel pathways “filter” (surveillance) lymph
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| * '''Immune''' - detect infections from peripheral tissues
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| ** skin, respiratory tract, gastrointestinal tract, etc.
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| * secondary lymphoid organ
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| * return extracellular fluid to circulation
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| | [[File:Lymph node structure.jpg|400px]]
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| |-
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| |}
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| ===Lymph Node Structure===
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| {| class="wikitable mw-collapsible mw-collapsed"
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| ! colspan=2|Lymph Node Structure
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| | [[File:Lymph node cartoon.jpg|400px]]
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| Simplified structure
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| | [[File:Lymph node cartoon 02.jpg|400px]]
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| Lymphocyte (T and B) Traffic
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| # Enter from high endothelial venules (HEVs also called post-capillary venules)
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| # Spend 8 to 24 h in the lymph node interstitium.
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| # Enter a network of medullary sinuses.
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| # Drain from sinuses into efferent lymphatic vessels.
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| |-
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| | [[File:Lymph node structure 02.jpg]]
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| | '''Lymph pathway'''
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| # Afferent vessel
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| # Subcapsular sinus
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| # Paratrabecular sinus
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| # Medullary sinus
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| # Efferent vessel
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| Watch T and B Lymphocytes Move
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| {{Lymph Node Movie 7}}
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| {{Lymph Node Movie 8}}
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| |}
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| ===Lymph Node Histology===
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| {| class="wikitable mw-collapsible mw-collapsed"
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| ! Lymph Node Histology
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| |-
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| * Capsule (thin) with trabecular or septa (dense connective tissue)
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| [[File:Lymph_node_cartoon_01.jpg|Lymph_node_cartoon_01.jpg|600px]]
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| {|
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| ! Fetal thymus
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| ! Young medulla
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| ! Young cortex
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| | [[File:Fetal thymus.jpg|300px]]
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| | [[File:Thymus - young 01.jpg|300px]]
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| | [[File:Thymus - young 02.jpg|300px]]
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| |}
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| {{Lymph node cartoons}}
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| |}
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| ==Lymph Nodes==
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| ===Lymph Node Structure===
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| [[File:Lymph_node_cartoon_01.jpg|Lymph_node_cartoon_01.jpg]]
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| Connective Tissue
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| * '''Capsule''' - dense connective tissue (irregular CT, some adipocytes))
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| * '''Trabeculae''' - dense connective tissue
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| * '''Reticular Tissue''' - Reticular cells and fibers, supporting meshwork (collagen type III)
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| ** Reticular cell produces reticular fibers ('''collagen type III''') and surrounds the fibers with its cytoplasm
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| ** reticular fibbers can also be produced by fibroblasts
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| <gallery>
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| File:Lymph node cartoon 03.jpg|Cartoon with histology features
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| File:Lymph node histology 01.jpg|Subcapsular Sinus (marginal sinus, continuation of trabecular sinus)
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| File:Lymph node histology 02.jpg|Follicle
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| File:Lymph node histology 03.jpg|Germinal Centre
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| File:Lymph node histology 04.jpg|Medullary Cords and Sinuses
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| File:Lymph node histology 05.jpg|High Endothelial Venules
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| File:Lymph_node_histology_06.jpg|Macrophages
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| </gallery>
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| {|
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| ===Lymphocyte (T and B) Traffic===
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|
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| # Enter from high endothelial venules (HEVs also called post-capillary venules)
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| # Spend 8 to 24 h in the lymph node interstitium.
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| # Enter a network of medullary sinuses.
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| # Drain from sinuses into efferent lymphatic vessels.
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| '''Important -''' Please note that the lymphocytes exit from the node by efferent lymphatic vessels.
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| [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A47 See Figure]
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| See also [[:File:Lymph node cartoon 02.jpg|Image - Cell Trafficking into and out of Lymph Nodes]].
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| | {{Lymph Node Movie 7}}
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| T and B motility
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| {{Lymph Node Movie 8}}
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| T and B interaction
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| |[[File:Lymph node histology 05.jpg|200px]]
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| High Endothelial Venules
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| See also [[:File:Lymph node - high endothelial venule.jpg|Lymphocyte Migration at High Endothelial Venule Model]]
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| |}
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| '''Links:''' [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A47 Immunobiology - Figure 1.8. Organization of a lymph node]
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