Talk:Draft 2016

Lymph Nodes

Lymph Node Anatomy

Lymph Node Anatomy
Location throughout the entire body - concentrated in axilla, groin, lung, gastrointestinal tract mesenteries Small (1 mm - 2 cm) encapsulated organ (diffuse lymphoid tissue - no capsule) Antigen transformed lymphocytes from the blood In lymph vessel pathways “filter” lymph Afferent - towards node (A - arrives at the node) Efferent - away from node (E - exits the node) Mesenteric lymph nodes

Lymph Node Functions

Lymph Node Functions
In lymph vessel pathways “filter” (surveillance) lymph Immune - detect infections from peripheral tissues skin, respiratory tract, gastrointestinal tract, etc. secondary lymphoid organ return extracellular fluid to circulation

Lymph Node Structure

Lymph Node Structure
Simplified structure	Lymphocyte (T and B) Traffic Enter from high endothelial venules (HEVs also called post-capillary venules) Spend 8 to 24 h in the lymph node interstitium. Enter a network of medullary sinuses. Drain from sinuses into efferent lymphatic vessels.
Lymph pathway Afferent vessel Subcapsular sinus Paratrabecular sinus Medullary sinus Efferent vessel	‎‎Lymph Node 7 Page | Play  ‎‎Lymph Node 8 Page | Play T and B motility

Lymph Node Histology

Lymph Node Histology
Capsule (thin) with trabecular or septa (dense connective tissue) Fetal thymus Young medulla Young cortex Lymph Node Cartoons: Detailed structure | Cartoon with Histology | Lymphocyte traffic | Simple structure | Simple node anatomy | Wiki node image | Internal structure | Mesenteric lymph node | Histology | Gallery | Lymph Node Development

Lymph Nodes

Lymph Node Structure

Connective Tissue

• Capsule - dense connective tissue (irregular CT, some adipocytes))
• Trabeculae - dense connective tissue
• Reticular Tissue - Reticular cells and fibers, supporting meshwork (collagen type III)
  • Reticular cell produces reticular fibers (collagen type III) and surrounds the fibers with its cytoplasm
  • reticular fibbers can also be produced by fibroblasts

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  Cartoon with histology features

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  Subcapsular Sinus (marginal sinus, continuation of trabecular sinus)

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  Follicle

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  Germinal Centre

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  Medullary Cords and Sinuses

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  High Endothelial Venules

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  Macrophages

Lymphocyte (T and B) Traffic Enter from high endothelial venules (HEVs also called post-capillary venules) Spend 8 to 24 h in the lymph node interstitium. Enter a network of medullary sinuses. Drain from sinuses into efferent lymphatic vessels. Important - Please note that the lymphocytes exit from the node by efferent lymphatic vessels. See Figure See also Image - Cell Trafficking into and out of Lymph Nodes.

‎‎Lymph Node 7 Page | Play T and B motility

‎‎Lymph Node 8 Page | Play T and B interaction

High Endothelial Venules See also Lymphocyte Migration at High Endothelial Venule Model

Links: Immunobiology - Figure 1.8. Organization of a lymph node