SFOS 6/7

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SFOS 6/7
2011-04-04 03:15:32
SFOS Lymphoid Organs Immune Response

SFOS 6/7
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  1. What cells have CD4?
    • CD4 - Helper T Cells
    • CD8 - Cytotoxic Cells
  2. What cells are effected by Natural Killer Cells and gd T lymphocytes?
    By what mechanism?
    • Tumor cells or virally-transformed cells
    • Release perforins and fragmentins or cytokines
  3. What defines an Antigen Presenting Cell?
    Give examples
    • Must express MHC Class II
    • Macrophages
    • Langerhans' cells in epidermis
    • Reticular dendritic cells of spleen/lymph nodes
  4. Define Antigen processing
    Intracellular conversion of native proteins into peptides and loading onto MHC molecules
  5. What presents endogenous antigens?
    Give examples
    Where does antigen processing take place?
    • MHC Class I
    • Virally infected cells, tumor antigens
    • Occurs in cytoplasm of infected/tumor cells
  6. What presents exogenous antigens?
    Give examples
    • MHC Class II
    • Bacterial infection
  7. What are the two types of cytokines and their associated responses?
    • Pro-inflammatory - cellular immune response
    • Anti-inflammatory - humoral immune response
  8. Describe the mechanism of interferons
    • Produced by virally infected cells
    • Activate natural killer cells
  9. What are lymph nodules?
    Give examples
    • Unencapsulated lymphoid tissue
  10. What are the structural and functional differences between primary and secondary nodules (follicles)?
    • Secondary nodules have pale Germinal Center, contains B-lymphoblasts (active proliferation)
    • Primary nodules - densely packed small lymphocytes
  11. What are Peyer's pathes and their associated structures?
    • Unencapsulated lymph nodules in ileum
    • Contain high endothelial venules (blood vessels)
    • M (microfold) cells - endocytose antigens
  12. 1. Are tonsils encapsulated?
    2. Describe the crypt structure of different tonsils
    1. Yes - dense connective tissue capsule

    • 2. Palatine tonsil - 10 to 20 deep crypts
    • Pharyngeal tonsil (adenoid) - no crypts
    • Lingual tonsil - single crypt
  13. What are the function of lymph nodes?
    Reaction to antigens presented to B lymphocytes by macrophages and follicular dentritic cells
  14. Define trabeculae
    Extensions of the capsule into the lymph tissue
  15. What are the structural framework cells/fibers of lymph nodes?
    Reticular cells/fibers
  16. Describe the path of lymph in a lymph node
    • Afferent lymphatic capillaries -->
    • Subcapsular sinuses -->
    • Trabecular sinuses -->
    • Medullary sinuses -->
    • Efferent lymphatic vessel
  17. Where do B cells differentiate?
    Interfollicular spaces in the cortex of lymph nodes
  18. Where are T Cells located in lymph nodes?
    Deep dense paracortical area
  19. Describe the splenic features:
    1. White pulp
    2. Periperal white pulp
    3. Red pulp
    4. Marginal zone
    • 1. T-lymph in Periarteriolar lymphatic sheaths (PALS), B-lymph in nodules
    • 2. B-cell area in white pulp
    • 3. Splenic cords and sinusoids
    • 4. Area between white and red pulp containing APCs
  20. Does the thymus have germinal centers or nodules?
    • NO!
    • Cortex is T Cells
  21. What tissue forms the thymus?
    Endoderm - epithelial reticular tissue
  22. What is thymic education and where does it take place?
    • Maturation of lymphatic stem cells
    • Cortex
  23. What prevents foreign antigens from reaching the thymic cortex?
    Blood-thymic barrier (type I cells)
  24. What are the types of epithelioreticular cells?
    • Type I - blood thymic barrier
    • Type II - express MHC I/II
    • Type III - express MHC I/II, cortex/medulla barrier
    • Type IV - cortex/medulla barrier
    • Type V - ?
    • Type VI - for Hassel's corpuscles (produce thymic hormones)