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Microbiology: Immune System and Immune Responses

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Terms in this set (28)

  • What is an immune response?
    A physiological process coordinated by the immune system to eliminate antigens.
  • Define innate immunity.
    Inborn, nonspecific immunity found in all eukaryotes with generalized responses to pathogens.
  • Define adaptive immunity.
    Immunity only in vertebrates that matures over time, tailors responses to pathogens, requires 4–7 days to activate, and exhibits memory.
  • What are the common features of innate and adaptive immunity?
    Both recognize diverse pathogens, eliminate identified invaders, and discriminate between self and foreign antigens.
  • What are the three lines of immune defense?
    1) Innate barrier defenses, 2) Innate cellular and molecular defenses, 3) Adaptive defense.
  • Examples of mechanical barriers in first-line defenses?
    Tears washing pathogens from eyes, urine flushing microbes, saliva limiting adherence, mucus membranes trapping microbes, mucociliary escalator sweeping mucus from lungs.
  • Role of lysozyme as a chemical barrier?
    An enzyme in secretions like tears and saliva that breaks down bacterial cell walls to attack invaders.
  • What are antimicrobial peptides?
    Proteins that destroy a wide spectrum of viruses, parasites, bacteria, and fungi; example: defensins.
  • What is the function of the lymphatic system in immunity?
    Collects, circulates, and filters fluid in body tissues before returning it to the blood, supporting immune cell function.
  • Primary lymphoid tissues and their roles?
    Thymus (site of T cell maturation) and bone marrow (site of red and white blood cell production).
  • Secondary lymphoid tissues and their functions?
    Lymph nodes (filter lymph), spleen (filters blood), and MALT (mucosa-associated lymphoid tissue) found in mucosal linings.
  • What are granulocytes?
    Leukocytes with visible cytoplasmic granules, including neutrophils, eosinophils, basophils, and mast cells.
  • What are agranulocytes?
    Leukocytes lacking visible granules, including lymphocytes, dendritic cells, and monocytes.
  • Role of neutrophils in immunity?
    Most numerous WBCs; perform phagocytosis, release antimicrobial peptides, and are first responders to injury.
  • What is phagocytosis?
    A process where cells engulf and digest large particles like bacteria or debris, also called 'cell eating.'
  • Function of eosinophils?
    Contain granules with enzymes and toxins; moderate phagocytic activity; involved in combating parasites.
  • Role of basophils and mast cells?
    Release histamine and other defense molecules; involved in allergic responses and fighting parasites.
  • What are cytokines?
    Signaling proteins that allow cells to communicate, initiating and coordinating immune responses.
  • What are chemokines?
    A type of cytokine that induces chemotaxis, attracting immune cells to sites of infection or injury.
  • How do siderophores help pathogens?
    Organic molecules produced by bacteria that sequester iron from host iron-binding proteins to support microbial survival.
  • What is the complement system?
    A group of >30 proteins that activate in a cascade to enhance immune defenses via opsonization, inflammation, and membrane attack complex formation.
  • What are the cardinal signs of inflammation?
    Redness, pain, localized heat, swelling, and loss of function.
  • Describe the vascular changes phase of inflammation.
    Blood vessels dilate and become more permeable, allowing immune cells and proteins to enter tissues; exudate accumulates to aid clotting.
  • What is margination in inflammation?
    The process where leukocytes slow down and adhere to blood vessel walls before exiting into tissues.
  • What is diapedesis?
    Leukocytes change shape and squeeze through blood vessel walls to reach infected or injured tissues.
  • How does fever protect the body?
    Limits growth of heat-sensitive pathogens, enhances interferon antiviral effects, increases phagocyte efficiency, and promotes tissue repair.
  • How do antipyretics reduce fever?
    By decreasing production of prostaglandins in the hypothalamus, which lowers the body's temperature set point.
  • What is chronic inflammation?
    A prolonged inflammatory response that causes tissue injury and contributes to diseases like atherosclerosis and certain cancers.