Microbiology - Innate Immunity (Ch. 15)

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Microbiology - Innate Immunity (Ch. 15)
2013-04-13 10:28:53

Microbiology - Innate Immunity (Ch. 15)
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  1. What is a virion?
    A viral particle that is existing outside of a cell. Basically a virus that is not in the process of infecting a cell.

    (15, 375 Lecture)
  2. What is the complement system?
    (Complement for short)
    A set of blood plasma proteins that act as chemotactic attractants, trigger inflammation and fever, and ultimately effect the destruction of foreign cells.

    (15, 447)
  3. What are chemotactic factors?
    Chemicals, such as peptides derived from complement and cytokines, that attract cells.

    (15, 444)
  4. What three ways can the complement system be activated?
    • 1) Classical pathway
    • 2) Alternate pathway
    • 3) Lectin pathway

    (15, 447)
  5. What are the two types of inflammation?
    • 1) Acute inflammation
    • 2) Chronic inflammation

    (15, 451)
  6. What are the three benefits of inflammation?
    • 1) Dilation and increased permeability of blood vessels.
    • 2) Migration of phagocytes
    • 3) Tissue repair

    (15, 451)
  7. What is a bradykinin?
    How is it created?
    • Bradykinin is a nine-amino-acid peptide chain that is a very powerful vasodilator and increases capillary permeability, thus being a potent mediator of inflammation.
    • The process of blood clotting trigger the conversion of a soluble plasma protein into the nine-amino-peptide chain called bradykinin.

    (15, 451)
  8. What is histamine?
    Histamine is an inflammatory chemical released from damaged cells that causes vasodilation of capillaries.

    (15, 452)
  9. What is an abscess?
    An isolated site of infection such as a pimple, boil, or pustule.

    (15, 452)
  10. What is margination?
    Margination is a process by which leukocytes stick to the walls of blood vessels at the site of an infection.

    (15, 452)
  11. What is pyrogen?
    Pyrogen is a chemical that triggers the hypothalamic "thermostat" to reset at a higher temperature, inducing fever.

    (15, 453)
  12. What type of cells secrete beta-interferon (IFN-β)?
    Virally infected fibroblasts, which are undifferentiated cells in connective tissues such as cartilage, tendon, and bone.

    (15, 447)
  13. Leukocytes can be divided into what two groups?
    • 1) Granulocytes
    • 2) Agranulocytes 

    (15, 442)
  14. What are goblet cells?
    Goblet cells are cells that are part of the epithelia that secrete extremely sticky mucous that traps bacteria and other pathogens.

    (15, 438)
  15. What are dermicidins?
    Dermicidins are a class of antimicrobial peptides secreted by the sweat glands. 

    (15, 437)
  16. What is lysozyme?
    Lysozyme is an enzyme that destroys cell walls of bacteria by cleaving the bonds between sugar subunits of the cell walls, leaving the bacteria susceptible to osmotic shock and other enzymes within phagocytes.

    (15, 437)
  17. What is the Lacrimal Apparatus? What 4 structures make it up?
    The lacrimal apparatus is a group of structures that produces and drains away tears.

    • It is composed of:
    • 1) Nasolacrimal duct
    • 2) Lacrimal canal
    • 3) Lacrimal gland duct
    • 4) Lacrimal glands

    (15, 439)
  18. What are macrophages?
    Macrophages are the mature form of a monocyte that are able to phagocytize bacteria, fungi, spores, dust, and dead cells.

    (15, 442)
  19. Compare trasnferrin, ferritin, and lactoferrin?
    All of these are transport proteins for iron.

    Transferrin transports protein to cells.

    Ferritin stores excess iron in the liver.

    Lactoferrin has a greater affinity for iron, and is used when certain bacteria come in and steal iron from transferrin. (Ex: Staphylococcus aureus and its iron-stealing proteins called siderophores)

    (15, 441)
  20. How do NETs (neutrophil extracellular traps) work?
    The neutrophil disintegrates its nuclei and the DNA and histones go into the cytosol and mix with cytoplasmic granule membranes and proteins to form NET fibers. Reactive oxygen species (superoxide and peroxide) then kill the neutrophil. The NETs are released and go trap gram+ and gram- bacteria, immobilizing them and sequestering them along with antimicrobial peptides, which then kill the bacteria.

    (15, 445-446)
  21. What are ciliated columnar cells?
    They are cells of the epithelia that use their cilia to propel the mucous and its trapped particles and pathogens up from the lungs.

    (15, 438)
  22. What two layers compose the epithelium?
    • 1) The epithelium, which are layers of cells that line hollow organs and glands.
    • 2) A deeper connective tissue layer that provides mechanical and nutritive support for the epithelium.

    (15, 438)
  23. What are antimicrobial peptides?
    What else are they known as?
    They are positively charged chains of 20-50 amino acids that act against microorganisms.

    They are also known as defensins

    (15, 437)
  24. What are dendritic cells?
    They are cells of the epidermis and mucous membranes that phagocytize pathogens and also play a role in adaptive immunity.

    (15, 437)
  25. Compare epidermis and dermis.
    Epidermis is the outer layer of the skin and the dermis is the inner layer which is much thicker and contains hair follicles, glands, and nerve endings.

    (15, 436)
  26. Compare innate vs. adaptive immunity.
    • Innate immunity is the resistance to pathogens by barriers, chemicals, cells, and processes that remain unchanged upon subsequent infections with the same pathogens.
    • Adaptive immunity, however, responds agains unique species or strains of pathogens and alters the body's defenses such that they act more effectively upon subsequent infections with that specific strain.

    (15, 436)
  27. What is species resistance?
    It is a property that protects a type of organism from infection by pathogens of other, very different organisms.

    (15, 436)
  28. What are two ways normal microbiota can inhibit pathogens?
    • 1) They compete for nutrients and space.
    • 2) They can change the environmental pH

    (15, 439)
  29. What triggers the release of antimicrobial peptides?
    The release of antimicrobial peptides is triggered by sugar and protein molecules on the external surfaces of microbes.

    (15, 440)
  30. Describe the makeup of plasma.
    Which part plays the greatest role in the body's defenses?
    • Plasma is mostly water containing electrolytes (ions), dissolved gases, nutrients, and a variety of proteins. 
    • Proteins play the greatest role in the body's defenses.

    (15, 440)
  31. What is hematopoiesis?
    • A process where blood stem cells (located primarily in the bone marrow of large bones) produce three types of formed elements. Which are: 
    • 1) Erythrocytes (red blood cells)
    • 2) Leukocytes (white blood cells)
    • 3) Platelets

    (15, 441)
  32. What is serum?
    Serum is the remaining liquid of plasma after clotting factors have been removed.

    (15, 441)
  33. What is apoptosis?
    Cell suicide.

    (15, 446)
  34. Although they can phagocytize, how do eosinophils typically kill microbes?
    They typically secrete antimicrobial chemicals that kill microbes.

    (15, 445)
  35. How do natural kill lymphocytes (NK cells) protect the body?
    They secret toxins onto the surfaces of virally infected cells and neoplasms.

    (15, 445)
  36. What is a phagolysosome?
    It is a phagosome that has been fused with a vesicle of lysosomes. When this happens the microbes that have been phagocytized begin to be destroyed.

    (15, 445)
  37. What is a phagosome?
    A phagosome is the vesicle by which the microbe is taken in during phagocytosis.

    (15, 445)
  38. What are the six steps of phagocytosis?
    • 1) Chemotaxis
    • 2) Adherence
    • 3) Ingestion
    • 4) Maturation
    • 5) Killing
    • 6) Elimination

    (15, 444-445)
  39. What is opsonization?
    Opsonization is the coating of pathogens by proteins called opsonins, making them more vulnerable to phagocytes.

    (15, 445)
  40. What type of cells secrete alpha interferon (IFN-α)?
    Virally infected monocytes, macrophages, and some lymphocytes. 

    (15, 447)
  41. What is sebum?
    Sebum is an oily substance secreted by sebaceous glands of the skin which lowers pH levels to about 5, inhibiting the survival of many microbes.

    (15, 437)
  42. What are formed elements?
    • Formed elements are cells and cell fragments suspended in blood plasma. 
    • Web Definition: one of the red blood cells, white blood cells, or blood platelets as contrasted with the fluid portion of the blood.

    (15, 441)
  43. What are toll-like receptors?
    What else are they known as?
    • Toll-like receptors are integral membrane proteins produced by phagocytic cells and trigger the body's response to molecules found on bacterial or viral pathogens but absent in humans.
    • They are also known as pathogen-associated molecular patterns, or PAMPS.

    (15, 446)
  44. What are NOD proteins?
    They are similar to TLRs, only located in the cells cytosol rather than its membrane.

    (15, 446)
  45. What are PAMPS?
    They are pathogen-associated molecular patterns. They are the molecules shared by a variety of microbes but are absent in humans and thus trigger immune responses.

    (15, 446)
  46. What cells produce gamma interferon (IFN-γ)
    What does it do?
    What's another name or it?
    • Gamma interferon is produced by activated T lymphocytes and NK lymphocytes.
    • It stimulates the activation of macrophages and is thus also known as the macrophage activation factor.

    (15, 447)
  47. What are interferons?
    • Interferons are protein molecules released by host cells to nonspecifically inhibit the spread of viral infections.
    • They are also what cause malaise, muscle aches, chills, headaches, and fevers associated with viral infections.

    (15, 447)
  48. What is diapedesis?
    What's another name for it?
    • Diapedesis is a process where leukocytes exit the blood to attack invading microbes in the tissue by squeezing between the cells lining the capillaries.
    • It is also known as emigration.

    (15, 442)
  49. In addition to phagocytosis, how else can neutrophils kill? (3 ways)
    • 1) They have enzymes that add electrons to oxygen, creating peroxide radicals (02-) and hydrogen peroxide (H2O). These are then turned into hyphochlorite via another enzyme, which kills nearby invaders.
    • 2) They can produce nitric oxide, an inducer of inflammation.
    • 3) They produce NETs (neutrophil extracellular traps).

    (15, 445-446)
  50. How are interferons categorized?
    • 1) Type I - Alpha and Beta. These are present early in viral infections and their actions are identical.
    • 2) Type II - Gamma. These appear later in the course of the infection.

    (15, 447)
  51. Agranulocytes come in what two types?
    • 1) Lymphocytes
    • 2) Monocytes

    (15, 442)