Lymph nodes Flashcards
What are lymph nodes?
Highly organised, bean-shaped structures at junctions between lymph vessels.
Where are lymph nodes aggregated?
In particular sites around the body such as the neck and groins.
What is the function of lymph nodes?
To filter lymph from tissues.
What happens to antigens in the lymph nodes?
They are trapped by the lymph nodes and taken up by antigen presenting cells.
What does the antigen presenting cell do once its picked up the antigen from inside the lymph nodes?
It is presented to lymphocytes which pass through the node.
Where do afferent lymphatics enter the node?
In the cortex, then pass through the paracortex and exit via the efferent lymphatic system in the medulla.
Where do High endothelial venues (HEVs) enter the lymph node?
In the paracortex.
Where are B cells located in the node?
In primary and secondary follicles in the cortex.
What are primary and secondary follicles?
Lymphoid tissues contain lymphoid follicles made up of lymphoid dendritic cells and B lymphocytes.
Primary follicles contain resting B lymphocytes and are then site at which germinal centres form when they are entered by activated B cells, forming secondary follicles.
Where are T cells mainly located in the node?
In the paracortex region.
How do antigens and cells pass through the lymph nodes?
Enter the lymph node through afferent lymphatics, through the node and exit via the efferent lymphatics.
How do lymphocytes and macrophages migrate through the lymph nodes?
They enter the HEVs at which point they are exposed to antigen. If the cell does not detect the antigen it is sensitive to it leaves via the efferent lymph node and later returns to the blood via the thoracic duct.
