Changes

==High endothelial venules==

==High endothelial venules==

<p> High endothelial venules (HEV) are composed of cuboidal/columnar epithelium and are the major route for lymphocytes to enter the node. HEV contain a large number of aquaporin-1 channels allowing for a large uptake of water which in turn drives lymph flow through the cortex. This fluid is then returned direct to the bloodstream. The venules are the source of most of the node's [[Lymphocytes#T cells|T cells]] and [[Lymphocytes#B cells|B cells]] and express selectins (receptors for lymphocytes primed with antigens).</p>

<p> High endothelial venules (HEV) are composed of cuboidal/columnar epithelium and are the major route for lymphocytes to enter the node. HEV contain a large number of aquaporin-1 channels allowing for a large uptake of water which in turn drives lymph flow through the cortex. This fluid is then returned direct to the bloodstream. The venules are the source of most of the node's [[Lymphocytes#T cells|T cells]] and [[Lymphocytes#B cells|B cells]] and express selectins (receptors for lymphocytes primed with antigens).</p>

<p>HEV express CD34 and GlyCAM-1 which bind to L-selectin on naive lymphocytes. This allows circulating [[Lymphocytes|lymphocytes]] to recognise when they have reached a [[Secondary Lymphoid Tissue - Anatomy & Physiology|secondary lymphoid organ]] and they leave the bloodstream, entering the lymphatic tissue.</P>

<p>HEV express CD34 and GlyCAM-1 which bind to L-selectin on naive lymphocytes. This allows circulating [[Lymphocytes|lymphocytes]] to recognise when they have reached a [[:Category:Secondary Lymphoid Tissue|secondary lymphoid organ]] and they leave the bloodstream, entering the lymphatic tissue.</P>

==Function==

==Function==

==Functions==

==Functions==

<p>The lymph nodes are [[Secondary Lymphoid Tissue - Anatomy & Physiology|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>