Biology Chapter 11: Innate Immunity Quiz
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Questions and Answers

What does the hygiene hypothesis suggest about normal microbiota?

  • A decrease in diversity in microbiota may harm immune responses. (correct)
  • Increased diversity in microbiota improves immune function.
  • Higher levels of normal microbiota seem to increase allergies.
  • Normal microbiota has no effect on immune responses.

    • What role do germ-free animals play in understanding immune system development?

  • Their immune systems develop normally.
  • They help illustrate the role of normal microbiota in immune development. (correct)
  • They thrive better than normal animals.
  • They require fewer nutrients compared to regular animals.

    • Which statement best describes the first-line defenses in the immune system?

  • They primarily involve chemical barriers with no mechanical or physical components.
  • They work to eliminate pathogens once they enter the body.
  • They are the final line of defense against infections.
  • Their main aim is to prevent pathogen entry through various barriers. (correct)

    • Which of the following is an example of a chemical barrier in first-line defenses?

    <p>Lysozyme found in tears.</p> Signup and view all the answers

    What are antimicrobial peptides known for?

    <p>Their basic role in providing defense against pathogens.</p> Signup and view all the answers

    What is the primary function of the thymus?

    <p>T cell maturation</p> Signup and view all the answers

    Which lymphoid tissue primarily produces B cells?

    <p>Bone marrow</p> Signup and view all the answers

    What is the primary role of lymph nodes in the immune system?

    <p>Filtration and screening of lymph</p> Signup and view all the answers

    What happens to lymph nodes upon detecting an invading microbe?

    <p>They become swollen</p> Signup and view all the answers

    Where is the spleen located in the human body?

    <p>Upper left part of the abdomen</p> Signup and view all the answers

    What is a significant indicator of infection related to lymph nodes?

    <p>Swollen nodes</p> Signup and view all the answers

    Which of the following statements about the bone marrow is true?

    <p>It is a site for maturation of B cells.</p> Signup and view all the answers

    How many lymph nodes do humans typically have in their bodies?

    <p>500–700</p> Signup and view all the answers

    What does a differential white blood cell (WBC) count determine?

    <p>If any leukocytes are over- or underrepresented in blood</p> Signup and view all the answers

    Which condition is characterized by an increase in neutrophils?

    <p>Neutrophilic leukocytosis</p> Signup and view all the answers

    Which leukocyte increase is typically linked to allergies or asthma?

    <p>Eosinophilia</p> Signup and view all the answers

    What is one role of active molecules released by activated leukocytes?

    <p>Recruiting other leukocytes to infection sites</p> Signup and view all the answers

    What typically causes basophilia?

    <p>Certain rare blood cancers</p> Signup and view all the answers

    Which leukocyte category includes T and B cells?

    <p>Lymphocytes</p> Signup and view all the answers

    Which leukocyte is primarily responsible for chronic infections and inflammation?

    <p>Monocytes</p> Signup and view all the answers

    What is a common characteristic shared by neutrophils, eosinophils, and basophils?

    <p>They are all types of leukocytes</p> Signup and view all the answers

    What role do complement proteins play during inflammation?

    <p>They increase vessel permeability and promote swelling.</p> Signup and view all the answers

    Which cells are primarily responsible for the release of histamine during the early stages of inflammation?

    <p>Mast cells</p> Signup and view all the answers

    What is the primary function of kinins in the inflammatory process?

    <p>They induce vascular changes and stimulate pain receptors.</p> Signup and view all the answers

    In what way do vasoactive molecules, like histamines, affect blood vessels?

    <p>They dilate blood vessels and increase permeability.</p> Signup and view all the answers

    Which of the following molecules assist in blood-clotting cascades as part of the inflammatory response?

    <p>Kinins</p> Signup and view all the answers

    What results from increased vessel permeability during inflammation?

    <p>Seepage of plasma and proteins into tissues.</p> Signup and view all the answers

    What type of molecules are primarily responsible for amplifying the inflammatory response?

    <p>Eicosanoids</p> Signup and view all the answers

    Which cells release vasoactive molecules during the inflammatory process?

    <p>Mast cells, basophils, and eosinophils</p> Signup and view all the answers

    What is the primary purpose of opsonization in the complement pathways?

    <p>To mark invaders for easier clearance by phagocytic cells</p> Signup and view all the answers

    Which pathway of complement activation does not require an antibody for its initiation?

    <p>Alternative pathway</p> Signup and view all the answers

    Which of the following correctly describes the role of complement proteins?

    <p>They promote inflammation and assist in cell lysis</p> Signup and view all the answers

    What initiates the lectin pathway of the complement cascade?

    <p>Binding of mannose-binding lectin to specific sugars</p> Signup and view all the answers

    Which mechanism is NOT a method of regulation for complement proteins?

    <p>Continuous activation in the presence of pathogens</p> Signup and view all the answers

    What are the cardinal signs of inflammation?

    <p>Redness, heat, swelling, and pain</p> Signup and view all the answers

    What happens during the formation of a membrane attack complex (MAC)?

    <p>Complement proteins create pores in the pathogen's membrane</p> Signup and view all the answers

    What role do chemoattractants play in the inflammation process?

    <p>They promote the rolling of leukocytes along blood vessel walls.</p> Signup and view all the answers

    Why is it important for complement proteins to be properly regulated?

    <p>To prevent excessive activation that can damage host tissues</p> Signup and view all the answers

    During the resolution phase of inflammation, which of the following occurs?

    <p>Blood vessels begin to revert to normal.</p> Signup and view all the answers

    What mechanism allows leukocytes to exit the blood vessel during inflammation?

    <p>Adhesion to the endothelium and squeezing through the vessel wall.</p> Signup and view all the answers

    What change occurs to leukocytes as they move along the vessel wall?

    <p>They elongate and adhere more strongly to the vessel walls.</p> Signup and view all the answers

    Which type of cell is primarily responsible for releasing chemoattractants?

    <p>Mast cells</p> Signup and view all the answers

    What is the purpose of exudate during inflammation?

    <p>To collect and contain inflammatory mediators and debris.</p> Signup and view all the answers

    How do activated leukocytes change as inflammation resolves?

    <p>They decrease in number and activity.</p> Signup and view all the answers

    What occurs during the rolling phase of leukocyte movement?

    <p>Leukocytes slow down and interact transiently with the endothelium.</p> Signup and view all the answers

    Study Notes

    Chapter 11: Innate Immunity

    • Innate immunity is a physiological process coordinated by the immune system to eliminate antigens.
    • It's an inborn, ancient protection found in all eukaryotic organisms.
    • Innate immunity is a generalized, non-specific response.
    • Innate immunity's common features include recognizing diverse pathogens, eliminating identified invaders, and discriminating between self and foreign antigens.
    • Adaptive immunity is found only in vertebrate animals and matures over time. It's specific to pathogens and requires 4-7 days to fully activate, longer than innate immunity.
    • Adaptive immunity exhibits memory.
    • Immune system is three collaborating lines of defense: barrier defenses, cellular and molecular defenses (Chapter 11), and adaptive defenses (Chapter 12)
    • Normal microbiota have a role in shaping immune responses and conferring protection. These microbes fine-tune the immune system to fight pathogens and tolerate non-pathogens, food, and self-tissues.
    • The hygiene hypothesis suggests a decrease in diversity and levels of microbes in the normal microbiota might negatively affect immune responses.
    • Studies of germ-free animals show that environments without microbes lead to underdeveloped immune systems, and that normal microbiota have a direct role in immune system development.
    • First-line defenses attempt to prevent pathogen entry. Subcategories include mechanical, chemical, and physical barriers.
    • Mechanical barriers include flushing, rinsing, and trapping actions like tears washing debris, urine flushing microbes, saliva limiting adherence, and mucus membranes trapping microbes. The mucociliary escalator sweeps away microbes in the lungs.
    • Chemical barriers directly attack invaders or establish environments that limit pathogen survival, such as lysozyme, stomach acid, and fatty acids.
    • Antimicrobial peptides (AMPs) are proteins that destroy a wide spectrum of viruses, parasites, bacteria, and fungi.

    Leukocytes Are Essential in All Immune Responses

    • Leukocytes are classified as granulocytes (cells with granules visible when stained in their cytoplasm) and agranulocytes (cells lacking granules).
    • Granulocytes include neutrophils, eosinophils, basophils, and mast cells.
    • Agranulocytes include monocytes (which mature to macrophages) and dendritic cells.
    • Lymphocytes (NK cells, B cells, and T cells) are approximately 25% of circulating white blood cells (WBCs).
      • NK cells are abundant in the liver and provide innate protection against viruses, bacteria, parasites, and tumor cells.
    • T cells and B cells coordinate the adaptive immune response, more detailed in Chapter 12.
    • White blood cell (WBC) counts (differential) diagnose infections if leukocytes are over- or underrepresented in a patient's blood.
    • Examples of leukocytoses include neutrophilic leukocytosis (increase in neutrophils), eosinophilia (increase in eosinophils), basophilia (increase in basophils), monocytosis (increase in monocytes), and lymphocytosis (increase in lymphocytes).

    Molecular Second-Line Defenses

    • Cytokines are signaling proteins that allow communication between cells, initiating and coordinating immune actions. Increasingly used for diagnosis and therapy.
    • Chemokines are a type of cytokine that attract white blood cells to areas of need.
    • Interferons (IFNs) are signaling molecules that function when pathogens (especially viruses) or tumor cells are detected.
    • Tumor necrosis factors (TNFs) are signaling proteins (primarily made by macrophages) that stimulate inflammation, kill tumor cells, and stimulate fever.
    • Iron-binding proteins (like hemoglobin, ferritin, lactoferrin, and transferrin) limit iron availability to microbes. Some pathogens have evolved methods to steal iron from this defense.
    • Complement proteins are >30 different proteins that work together in a cascade fashion. The system gets activated and enhances immune defenses.

    Inflammation and Fever

    • Inflammation is an essential part of innate immunity and healing in response to tissue damage.

    • The three main goals of inflammation are recruiting immune defenses to injured tissue, limiting the spread of infectious agents, and delivering oxygen, nutrients, and chemical factors for tissue recovery.

    • Cardinal signs of inflammation include redness, pain, localized heat (not fever), swelling, and loss of function.

    • Inflammation occurs in three phases: vascular changes, leukocyte recruitment, and resolution.

    • A fever is an abnormally high body temperature caused by pyrogens (e.g., toxins, cytokines.) which signals the hypothalamus to raise the body's baseline temperature.

    • Studies suggest that fever enhances antiviral effects of interferons, increases phagocyte efficiency, enhances leukocyte production, limits pathogens, and promotes tissue repair.

    • Low-grade fever (37.5°C to 38.3°C (99.5- 101°F)) is often considered protective.

    • Antipyretics (such as aspirin, ibuprofen, or acetaminophen) reduce fever by limiting prostaglandin production in the hypothalamus. A fever that doesn't decrease with treatment above 40.5 °C (105°F) should be treated as an emergency.

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    Description

    Test your knowledge on the fundamentals of innate immunity as discussed in Chapter 11. This quiz covers the physiological processes of the immune system, distinguishing features of innate versus adaptive immunity, and the role of normal microbiota in immune responses. Challenge yourself with questions about this vital aspect of biology.

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