End of Chapter 14/ Beginning of 15

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End of Chapter 14/ Beginning of 15
2010-07-07 12:14:02
Defense Systems

SCC Microbio Summer 2010
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  1. Compromised Host
    • 1. damaged physical barriers: broken skin and
    • mucous membranes. (use of intravenous devices)

    2. suppressed immune system.
  2. Chain of Transmission
    • 1. Direct contact: From hospital staff to patient and from patient to patient.
    • 2. Indirect contact- through fomites
    • 3. Hospital ventilation systems (air borne transmission)
  3. First Line of Defense
    • Intact skin
    • Mucous membranes and their secretions
    • normal microbiota
  4. Second line of defense
    • phagocytic WBCs
    • Infalmmation
    • Fever
    • Antimicrobial substances
  5. Non-Specific Defense (Innate/ inborn immune response)
    • Same immune response against any type of pathogen.
    • Faster response time
    • No memory of previous exposure
  6. Non-specific immune responses consists of
    First and second lines of defense
  7. Skin as a first line of defense
    • 1. Sebum/oil- rich in fatty acid --> acidic pH on skin
    • 2. Keratinized epidermis keeps the skin dry
    • 3. Closely packed cells
    • 4. Periodic shedding of skin cells
    • 5. Sweat, high salt concentration
    • 6. Lysoszyme (in sweat) (damages peptidoglycan) and hurts GM+ bacteria
  8. Mucous membrane protective membrane
    • 1. In conjunctiva of eyes: tears (rich in salt and lysozyme) tears flush eyes out
    • 2. Respiratory: ciliary living (ciliary escalator), Lysoszyme
    • 3. In GI tract: Acidic pH (gastric juice) preistalsis (movement through GI Tract)
    • 4. Gastroferritin- Reduces iron for pathogen
  9. Genitourinary tract as a protective factor of mucous membrane
    • Urine- Flushes the urinary tract
    • Vaginal pH and normal flora is acidic (prevents pathogen growth)
  10. MIcrobial antagonism
    Competition among microbes (observed b/w normal microbiota and pathogens) for common growth factors
  11. Normal microbiota protect host by
    • -Occupying niches that pathogens might occupy (habitats, receptors on host tissue)
    • - Producing acids
    • - Producing bacteriocins
    • -Changing oxygen availability
  12. Second Line of Defense
    • 1. Complement System
    • 2. Inflammation
    • 3. Phagocytosis
    • 4. Fever
    • 5. Antimicrobial compounds (Interferons, Transferrin, Antimicrobial peptides)
  13. Components of Blood
    Plasma and Formed elements

    • RBC- Erythrocytes (transport gases)
    • WBC- Leukocytes (defense)
    • Platelets- Thrombocytes (blood clotting)
  14. Types of White Blood Cells
    • 1. Granulocytes
    • 2. Agranulocytes
  15. Types of Granulocytes
    • 1. Neutrophils
    • 2. Basophils
    • 3. Eosinophils

    Cells have granules that are stained easily
  16. Neutrophils
    • Perform Phagocytosis
    • Usually the first to reach the site
  17. Basophils
    Produce histamine
  18. Eosinophil
    • Allergic response
    • Destroy parasitic worms (helminths)
  19. Type of Agranulocytes
    • Monocytes (macrophages)
    • Lymphocytes (Natural killer cells, T cells, B Cells)
  20. Monocytes
    Large nucleus, mature to macrophages (phagocytosis)
  21. 2 categories of macrophages
    Wandering-(Can leave blood vessels and reach infection)

    Fixed- (non motile), localized to specific tissue Ex- Microglia cells (nervous tissue) Kupffer cells (liver)
  22. Dendritic Cells
    Underneath skin; use phagocytosis
  23. 3 Types of Lymphocytes
    • Natural Killer (NK) cell
    • T Cells
    • B Cells
  24. Natural Killer Cells (NK cells)
    Destroy infected cells of the body and tumor cells (non-specifically)
  25. B Cells
    Antibody production
  26. T Cells
    Helper T Cells (Th)- Secrete cytokine (Chemical messenger) and activates other cells (B cells, T cytotoxic cells)

    Cytotoxic T Cells (Tc)- Destroys infected cells and tumor cells, specific response
  27. Cells of specific immune response
    B cells, T cells (lymphocytes)
  28. High esinophil count during
    Allergies and helminth infections
  29. High neutrophil count during
    Bacterial infection
  30. High lymphocyte count during
    viral infections, chronic infections
  31. Blood Plasma
    Fluid, still has blood clotting factor; then centrifuge to separate blood cells from serum
  32. Blood serum
    • No clotting factor present
    • Rich in antibodies, used to diagnose an infection by detecting presence of specific antibodies against pathogens