Term
| What is the pathway through a lymph node? |
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Definition
| -Afferent lymphatic or HEV (if from blood), subcapsular sinus, cortex (contains follicles/germinal centers), paracortex, medulla, medullary sinus, then out through hilum of efferent lymphatic vessel |
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Term
| How are the spleen lymphatics organized? |
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Definition
-In through single splenic artery, to central arteriole which is surrounded by the periarteriolar lymphoid sheaths (PALS), next to that is the B cell corona with germinal centers, and surrounding those two zones is the marginal sinus, and finally the marginal zone
-This all comprises the "white pulp"
-The spleen ultimately drains into portal circulation |
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Term
| What are the B and T cell zones of the lymph nodes and spleen? |
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Definition
-B cells are found in periphery of both; in the follicles of the lymph node cortex and in the corona/follicles of the spleen (just outside the PALS)
-T cells are found more centrally; in the paracortex and PALS |
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Term
| What do we find in the inner medulla? |
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Definition
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Term
| How do lymphocytes get from blood to lymphatics and vice versa? |
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Definition
-To lymph nodes they use high endothelial veins
-Back to blood they use the thoracic duct |
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Term
| How does a lymphocyte migrate to HEVs? |
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Definition
-They have L-selectins (on naive cells only) which weakly bond with addressins on HEV walls
-"Lymphocytes Slide Along" |
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Term
| How often do lymphocytes pass through the secondary lymph organs? |
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Definition
| -They pass through every lymph node in the body about once a day and the spleen every other day, on average |
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Term
| What is the organization and purpose of follicles? |
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Definition
-They are where the B cells reside
-When they start to divide, they will become secondary follicles
-The center of the follicles are referred to as germinal centers where all the class switching and reproduction is happening for B cells
-This is the area that expands in infection
-The follicles are located in the cortex |
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