Term
| What are the primary/central lymphoid organs? |
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Definition
-Bone marrow and thymus
-Classified as where they arise and mature |
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Term
| What are the secondary/peripheral lymphoid organs? |
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Definition
-lymph nodes, spleen, MALT (mucosal ass. lymphoid tissue)
-filter and trap antigens providing an environment for lymphocytes to find them |
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Term
| What form of T cell arrives at the thymus and what happens? What are the C4, C8, and TCR status changes? |
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Definition
-Pre-T cells arrive at the outer cortex and mature as they move to the medulla
-They go from all negative to all positive (double positive), and then to single positive |
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Term
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Definition
-DeGeorge's syndrome
-Won't have T cells and will suffer repeated infections |
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Term
| What are the areas of a typical lymph node and what do they contain? |
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Definition
Outer cortex (B cells)
-has primary and secondary follicles with the secondary serving as germinal centers that expand during infection
Paracortex (T cells)
-Where dendrite cells present antigens to T cells (which then travel either out as CTLs, or to the secondary follicles to activate B cells as Th cells)
Medulla (T cells, B cells, plasma cells, macrophages |
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Term
| Describe the spleen tissues? |
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Definition
-Has red and white pulp
White pulp can be broken down into;
-Periarteriolar sheets (PALS) - with T cells and presenting dendrites
-Primary and secondary follicles - B cells are activated by T cells in the primary and then go on to form secondary follicles/germinal centers
-A marginal zone surrounds and is where antigens are trapped by APCs |
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Term
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Definition
-Fatal
-However, if removed later in life, it's not a major problem |
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Term
| Where are dendrites and macrophages in the secondary organs? |
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Definition
-Dendrites tend to be where the T cells are
-Macrophages tend to be in the periphery where they act as antigen filters |
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Term
| What are the major immune cells of skin? |
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Definition
-CD8+ cells and dendrites (called Langerhans' cells)
-Keratinocytes are also present and can secrete cytokines |
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Term
| What is GALT and what is an examples of it? |
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Definition
-it is the gut associated lymphoid tissue
-Peyer's patches
-Think GALT is technically a type of MALT
-BALT is another example (bronchial-) |
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Term
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Definition
| -They are cells in the MALT which are able to transport antigens and microorganisms from the lumen of the intestine to immune cells in pockets they contain |
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Term
| What specialized channels do lymphocytes use to get from blood back to lymph? |
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Definition
-They use HEVs (high endothelial venues) which have specialized cells that respond to chemokines and permit access by lymphocytes
-Niave T cells find HEVs by using L-selectin molecules
-The lymphocytes will go through the nodes and exit if the cells there don't show them any antigens |
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Term
| How do memory and effector T-cells find their targets? |
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Definition
-They, like neutrophils, seek out ICAM-1 (or VCAM) (intercellular and vascular cell adhesion molecules)
-However, they use LFA-1 (lymphocyte function-associated antigen 1) to bind them (an integrin) |
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