Changes

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

[[Image:LH_Lymph_Node_Follicle_Histology.jpg|thumb|150px|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 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 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]] and afferent 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 [[Lymphocytes - WikiBlood#T cells|T cells]], [[Lymphocytes - WikiBlood#B cells|B cells]] and [[T cell differentiation - WikiBlood#Dendritic Cells|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 [[Lymphocytes - WikiBlood#T cells|T cells]], [[Lymphocytes - WikiBlood#B cells|B cells]] and [[T cell differentiation - WikiBlood#Dendritic Cells|dendritic cells]].  

*Medullary

*Medullary

Antigens and transformed cells that pass through the sinuses are filtered by [[Macrophages - WikiBlood|macrophages]] and removed from the lymph.</p>

Antigens and transformed cells that pass through the sinuses are filtered by [[Macrophages - WikiBlood|macrophages]] and removed from the lymph.</p>

==Follicles==

==Follicles==

<p>Lymph nodes have two types of follicles primary and secondary. Secondary follicles contain germinal centres (sites of B-cell proliferation) and have three layers.  

<p>Lymph nodes have two types of follicles primary and secondary. Secondary follicles contain germinal centres (sites of B-cell proliferation) and have three layers.