Changes

[[Image:Lymph Node positions.jpg|thumb|right|150px|Positions of the lymph nodes (dog) - Copyright B.Catchpole RVC]]

 

[[Image:Lymph Node positions.jpg|thumb|right|250px|Positions of the lymph nodes (dog) - Copyright B.Catchpole RVC]]

[[Image:Aspinall Slide11.JPG|thumb|right|250px|<small>Image from [http://www.elsevierhealth.co.uk/veterinary-nursing/spe-60136/ Aspinall, The Complete Textbook of Veterinary Nursing], Elsevier Health Sciences, ''All rights reserved''</small>]]

==Introduction==

==Introduction==

''For haemolymph nodes click [[Haemolymph Nodes - Anatomy & Physiology|here]]''

''For haemolymph nodes click [[Haemolymph Nodes - Anatomy & Physiology|here]]''

[[Image:LH Lymph Node Diagram.jpg|thumb|150px|right|<p>'''Diagram'''</p>]]

[[Image:LH Lymph Node Diagram.jpg|thumb|250px|right|<p>'''Diagram'''</p>]]

<p>Part of the [[Lymphatic System - Anatomy & Physiology|lymphatic system]], the body contains hundreds of lymph nodes of varying size (1-20mm) and these are located along the routes of [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessels]]. They are found throughout the body but are more concentrated in the axilla, groin and mesenteries. Lymph nodes act as a filter for the lymph removing antigens and releasing immune-competent cells and immunoglobulins.</p>

<p>Part of the [[Lymphatic System Overview - Anatomy & Physiology|lymphatic system]], the body contains hundreds of lymph nodes of varying size (1-20mm) and these are located along the routes of [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessels]]. They are found throughout the body but are more concentrated in the axilla, groin and mesenteries. Lymph nodes act as a filter for the lymph removing antigens and releasing immune-competent cells and immunoglobulins.</p>

==Development==

==Development==

<p>Lymph nodes develop from lateral plate mesoderm in paired sacs from [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessels]]. These sacs undergo remodelling, and endothelial and mesenchymal outgrowths form the meshwork of channels and spaces that produces the cortex-medulla structure. Lymphocytes then populate the cortex and medulla. The subcapular sinus is a remainder of the [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessel]].</p>

<p>Lymph nodes develop from lateral plate mesoderm in paired sacs from [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessels]]. These sacs undergo remodelling, and endothelial and mesenchymal outgrowths form the meshwork of channels and spaces that produces the cortex-medulla structure. Lymphocytes then populate the cortex and medulla. The subcapular sinus is a remainder of the [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessel]].</p>

==Structure==

==Structure==

[[Image:LH_Lymph_Node_Follicles_Histology.jpg|thumb|150px|right|<p>'''Primary & secondary follicles'''</p>^{©Nottingham Uni 2008}]]

[[Image:LH_Lymph_Node_Follicle_Histology.jpg|thumb|150px|right|<p>'''Secondary Follicle'''</p>^{©RVC 2008}]]

[[Image:LH_Lymph_Node_Follicles_Histology.jpg|thumb|250px|right|<p>'''Primary & secondary follicles'''</p>^{©Nottingham Uni 2008}]]

[[Image:LH_Lymph_Node_Follicle_Histology.jpg|thumb|250px|right|<p>'''Secondary Follicle'''</p>^{©RVC 2008}]]

===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 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]]. Afferent vessels enter the node on its convex side and efferent vessels exit on its concave side.</p>

<p>Grossly the lymph nodes are round or bean shaped and have an outer cortex and an inner medulla. Microscopically the nodes have 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]]. Afferent vessels enter the node on its convex side and efferent vessels exit on its concave side.</p>

<p>The lymph nodes are [[:Category:Secondary Lymphoid Tissue|secondary lymphoid tissue]], and as the [[Spleen - Anatomy & Physiology|spleen]] removes antigens from the blood, lymph nodes remove antigens from tissue/lymph. Antigen presenting cells ([[Lymphocytes#B cells|B cells]] and [[Lymphocytes#T cells|T cells]]) migrate from peripheral tissue via afferent [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessels]] to the lymph nodes where they present their antigen to lymphocytes. [[Lymphocytes#B cells|B cells]] and [[Lymphocytes#T cells|T cells]] enter via the high endothelial venules by diapedesis and [[Lymphocytes#B cells|B cells]] migrate to the cortex while [[Lymphocytes#T cells|T cells]] to the deep cortex.</p>

<p>The lymph nodes are [[:Category:Secondary Lymphoid Tissue|secondary lymphoid tissue]], and as the [[Spleen - Anatomy & Physiology|spleen]] removes antigens from the blood, lymph nodes remove antigens from tissue/lymph. Antigen presenting cells ([[Lymphocytes#B cells|B cells]] and [[Lymphocytes#T cells|T cells]]) migrate from peripheral tissue via afferent [[Lymphatic Vessels - Anatomy & Physiology|lymphatic vessels]] to the lymph nodes where they present their antigen to lymphocytes. [[Lymphocytes#B cells|B cells]] and [[Lymphocytes#T cells|T cells]] enter via the high endothelial venules by diapedesis and [[Lymphocytes#B cells|B cells]] migrate to the cortex while [[Lymphocytes#T cells|T cells]] to the deep cortex.</p>

<p>Antibodies and immunologically competent cells leave the lymph nodes via the efferent lymphatics.</p>

<p>Antibodies and immunologically competent cells leave the lymph nodes via the efferent lymphatics.</p>

 

[[Category:Lymph Nodes|A]]

[[Category:Lymph Nodes|A]]