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Lymph Nodes - Anatomy & Physiology (view source)
Revision as of 15:56, 21 July 2008
, 15:56, 21 July 2008→Structure
[[Image:LH_Lymph_Node_Follicle_Histology.jpg|thumb|150px|right|<p>'''Secondary Follicle'''</p><sup>©RVC 2008</sup>]]
[[Image:LH_Lymph_Node_Follicle_Histology.jpg|thumb|150px|right|<p>'''Secondary Follicle'''</p><sup>©RVC 2008</sup>]]
===General===
===General===
<p>Grossly the lymph nodes are round or bean shaped and have an outer cortex and an inner medulla. Microscopically the nodes have a follicles, paracortical zones and medullary cords and sinuses. At the hilum the medulla is present on the outer part of the node.</p>
<p>Grossly the lymph nodes are round or bean shaped and have an outer cortex and an inner medulla. Microscopically the nodes have a follicles, paracortical zones and medullary cords and sinuses. At the hilum the medulla is present on the outer part of the node. Lymph nodes are located in series with [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessels]] and afferent lymphatic vessels enter the node on its convex side and efferent vessels exit on its concave side.</p>
====Capsule and reticular framework====
====Capsule and reticular framework====
<p> The nodes are surrounded in a fibrous capsule that extends into the node as trabeculae, which provide an overall framework. Below the capsule is the sub-capsular sinus. The nodes parenchyma contain a fine network of reticular fibres and reticular cells. Reticular cells provide "scaffolding" for other cells as well as expressing surface complexes and substance to attract T,B and dendritic cells.
<p> The nodes are surrounded in a fibrous capsule that extends into the node as trabeculae, which provide an overall framework. Below the capsule is the sub-capsular sinus. The nodes parenchyma contain a fine network of reticular fibres and reticular cells. Reticular cells provide "scaffolding" for other cells as well as expressing surface complexes and substance to attract T,B and dendritic cells.
Image:LH_Lymph_Node_Follicular_layers_Histology.jpg|<p>'''Follicular layers'''</p><sup>©RVC 2008</sup>
Image:LH_Lymph_Node_Follicular_layers_Histology.jpg|<p>'''Follicular layers'''</p><sup>©RVC 2008</sup>
Image:LH_Lymph_Node_HEV_Histology.jpg|<p>'''High endothelial venule'''</p><sup>©Nottingham Uni 2008</sup></gallery>
Image:LH_Lymph_Node_HEV_Histology.jpg|<p>'''High endothelial venule'''</p><sup>©Nottingham Uni 2008</sup></gallery>
==Functions==
==Functions==
<p>The lymph nodes are [[Secondary Lymphoid Tissue - Anatomy & Physiology|secondary lymphoid tissue]], and as the spleen removes antigens from the blood, lymph nodes remove antigens from tissue/lymph. Antigen presenting cells (B and T cells) migrate from peripheral tissue via afferent lymphatic vessels to the lymph nodes where they present their antigen to lymphocytes. B cells and T cells enter via the high endothelial venules by diapedesis and B cells migrate to the cortex while T cells to the deep cortex.</p>
<p>The lymph nodes are [[Secondary Lymphoid Tissue - Anatomy & Physiology|secondary lymphoid tissue]], and as the spleen removes antigens from the blood, lymph nodes remove antigens from tissue/lymph. Antigen presenting cells (B and T cells) migrate from peripheral tissue via afferent lymphatic vessels to the lymph nodes where they present their antigen to lymphocytes. B cells and T cells enter via the high endothelial venules by diapedesis and B cells migrate to the cortex while T cells to the deep cortex.</p>