Gastrointestinal Defense Mechanisms S2M2

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Gastrointestinal Defense Mechanisms S2M2
2011-08-13 18:29:50
Ross S2M2

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  1. What is the first line of defense of inhaled and ingested microorganisms
  2. What are the immune defenses found in the oral cavity
    • Saliva
    • Tonsils
    • Tight Junctions
    • Mucous membranes
    • Epithelium
  3. What is found in the tonsils providing immune protection
    Macrophages and Lymphocytes
  4. What are the elements in Saliva that make it protective
    • Amylase
    • Bicarbonate
    • Lysosymes
    • RNAse
    • DNAse
    • Mucus
    • Epidermal Growth Factor (EGF)
    • IgA
    • "REDI...... BLAM saliva man!"
  5. What elements of the stomach protect it from microorganisms
    • Mucus
    • Bicarbonate
    • G cells that secrete Gastrin stimulating
    • - Parietal cells to release HCl
    • - Chief cells to secrete Pepsinogen
  6. Zollinger-Ellison Syndrome
    Hypersecretion of HCl from the stomach causing gastric ulcers
  7. What are the components of intestinal immune defense
    • Mucus production
    • Epithelium
    • Peristalsis
    • Microbiota
    • Microfold cells
    • Paneth cells
    • Peyers patches
  8. What is the most important immune response in the intestines
    • Abundance of Lymphoid tissue
    • There is more lymph in the intestines then any where else in the body
  9. What are the antimicrobial substances that the intestine secretes
    • Bacteriocins
    • Colicins
    • Defensins
    • Lactoferrin
    • Lysozyme
  10. What do the intestines secrete to attract monocytes, macrophages, and dendritic cells
  11. Tollip
    • Toll interacting protein
    • This inhibits TLR from reacting to commensal organisms as well as decreasing the Kinase activity in response to TLR's
  12. How do the intestinal cells recognize antigens
    Toll like receptors (TLR) on the intestinal cells bind Pathogen associated molecular patterns (PAMP's) and Microbial associtated patterns (MAMP's)
  13. The intestines contain many foreign microbes, why isn't it then constantly in an immune response mode
    The intestines have the ability to discriminate between commensal organisms and pathogens
  14. What is the significance of TLR4 expressed in the intestines
    TLR4 are poorly expressed in intestinal cells and are therefore poorly responsive to Gram negative bacteria resulting in a muted response to commensal organisms
  15. What are the three ways that the intestines can test an antigen
    • Enterocyte pathway
    • M-cells
    • Dendritic cells sending extensions through tight junctions into the lumen of the Gut
  16. What is the Enterocyte pathway
    Internalizing a pathogen via receptor mediated endocytosis, and then presenting it to lymphoid cells to decide whether an immune response in warranted
  17. M cell
    Specialized epithelial cell overlying the Peyers patches with the ability to transport antigens to dendritic cells to determine if an immune response is necessary
  18. Transcytosis
    The process of an M cell in the intestines that takes in antigens and transports them to dendritic cells in the Peyers patches for immune responses
  19. How do Paneth cells in the intestines assist in protection of the gut
    Paneth cells are the scavenger cells of the intestine with the ability to mount phagocytic responses
  20. When Paneth cells are stimulated by foreign microorganisms they release
    • Alpha defensins
    • Lysozyme
    • Phospholipase A2
  21. What is the role of Peyers patches in immune responses in the intestines
    Located in the mucosa and submucosa, Peyers patches are large lymphoid follicles that contain B cells for immune responses
  22. When B cells in the Peyers patches are activated what do they differentiate into
    IgA antibody producing cells