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Lymph Nodes - Anatomy & Physiology (view source)
Revision as of 16:49, 24 September 2010
, 16:49, 24 September 2010→High Endothelial Venules
<p>Follicles in the cortex of a stimulated node are larger and have a pale germinal centre. Activated [[Lymphocytes#B cells|B cells]] differentiate into plasma and memory cells. Plasma cells migrate to the medullary cords and produce immunoglobulins.</p>
<p>Follicles in the cortex of a stimulated node are larger and have a pale germinal centre. Activated [[Lymphocytes#B cells|B cells]] differentiate into plasma and memory cells. Plasma cells migrate to the medullary cords and produce immunoglobulins.</p>
==[[High Endothelial Venules]]==
==High Endothelial Venules==
High endothelial venules (HEV) are composed of cuboidal/columnar epithelium and are the major route for lymphocytes to enter the lymph 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 directly to the bloodstream. The venules are the source of most of the node's T cells and B cells and express selectins (receptors for lymphocytes primed with antigens).
HEV express CD34 and GlyCAM-1 which bind to L-selectin on naive lymphocytes. This allows circulating lymphocytes to recognise when they have reached a secondary lymphoid organ stimulating them to leave the bloodstream and enter the lymphatic tissue.
==Function==
==Function==