Physiological Barriers in Immunology
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Questions and Answers

What initiates the migration of phagocytes during chemotaxis?

  • Pressure on nerve endings
  • Arrival of lymphatic fluid
  • Chemical substances as signals (correct)
  • Loss of tissue fluid

    • Which type of white blood cell is the first to arrive at the site of inflammation?

  • Basophils
  • Macrophages
  • Lymphocytes
  • Neutrophils (correct)

    • What is the primary role of the fluid delivered to the site of injury during inflammation?

  • To deliver proteins important for clotting (correct)
  • To act as a barrier against pathogens
  • To provide nutrients to the surrounding tissues
  • To increase lymphatic drainage

    • What is the effect of the 'walling-off' process in inflammation?

    <p>Blocking of tissue spaces and lymphatics</p> Signup and view all the answers

    Which of the following molecules primarily acts as a honing device for phagocyte migration?

    <p>Specific chemical substances</p> Signup and view all the answers

    What is a primary reason vaccines are effective in conferring lifelong immunity?

    <p>They promote self/non-self recognition in the immune system.</p> Signup and view all the answers

    What do autoimmune diseases primarily stem from?

    <p>Dysfunctional self/non-self recognition</p> Signup and view all the answers

    Which cells are predominantly involved in the adaptive immune response?

    <p>B-cells and T-cells</p> Signup and view all the answers

    What must occur for a foreign antigen to be recognized by a T-cell?

    <p>The antigen is processed and then presented by cells.</p> Signup and view all the answers

    Which statement best describes antigen processing?

    <p>Pathogens are graded to produce small antigenic particles for recognition.</p> Signup and view all the answers

    How does the immune system respond to foreign antigens?

    <p>By distinguishing them from self through high specificity.</p> Signup and view all the answers

    What role do peptides play in the immune response?

    <p>Peptides are fragments of non-self antigens that are presented to T-cells.</p> Signup and view all the answers

    What is the main function of T-cells in the adaptive immune system?

    <p>Directly attacking infected cells or coordinating the immune response.</p> Signup and view all the answers

    What role does low pH play in the body's defense mechanisms?

    <p>It kills most ingested microorganisms.</p> Signup and view all the answers

    Which of the following is a function of inflammatory cytokines?

    <p>They induce fever to inhibit pathogen growth.</p> Signup and view all the answers

    What is the primary function of lysozyme?

    <p>To cleave bacterial cell walls leading to their death.</p> Signup and view all the answers

    Which cells are primarily responsible for directly killing infected or cancerous cells?

    <p>Cytotoxic T-cells and NK cells</p> Signup and view all the answers

    How does the body respond to fever in terms of pathogen defense?

    <p>It enhances the immune response.</p> Signup and view all the answers

    What does the Class II-associated Invariant chain Polypeptide (CLIP) do?

    <p>Digests extracellular pathogens into peptide fragments</p> Signup and view all the answers

    Which statement describes phagocytosis?

    <p>It refers to the ingestion of large foreign materials.</p> Signup and view all the answers

    Which statement about T-cell interaction with MHC molecules is correct?

    <p>T-cells interact only with peptide fragments of MHC molecules</p> Signup and view all the answers

    Which interleukin is primarily associated with allergic reactions and helminthic responses?

    <p>IL-4</p> Signup and view all the answers

    What condition makes neonates more susceptible to gastrointestinal infections?

    <p>Less developed gut flora.</p> Signup and view all the answers

    What is the first step in the inflammatory response following tissue damage?

    <p>Release of histamines.</p> Signup and view all the answers

    Which of the following statements is true about the binding of T-cells to MHC molecules?

    <p>T-cells specifically bind to MHC-II via their receptors</p> Signup and view all the answers

    What is the role of antigen-presenting cells in the immune response?

    <p>They present antigens to T-cells</p> Signup and view all the answers

    Which of the following statements about macrophages is true?

    <p>They are capable of phagocytosing whole microorganisms.</p> Signup and view all the answers

    Which of the following is NOT a characteristic of innate immunity?

    <p>Specificity for particular pathogens</p> Signup and view all the answers

    What is the function of cytokines produced by activated T-cells?

    <p>Regulate and enhance immune responses</p> Signup and view all the answers

    Which statement is true regarding affinity maturation in B cells?

    <p>Affinity maturation remains constant as the humoral response progresses.</p> Signup and view all the answers

    What triggers anergy in T cells?

    <p>A lack of co-stimulation during T cell activation.</p> Signup and view all the answers

    What is the effect of heavy chain isotype switching?

    <p>It enables B cells to create different antibody classes for immune responses.</p> Signup and view all the answers

    Which of the following antibodies is primarily involved in mucosal immunity?

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

    In what scenario might a cytokine storm impact T cells negatively?

    <p>When the storm overwhelms the regulatory mechanisms in T cells.</p> Signup and view all the answers

    What is a primary outcome of effective isotype switching to IgE in B cells?

    <p>Enhanced response to helminth infections.</p> Signup and view all the answers

    Which statement regarding somatic maturation in B cells is accurate?

    <p>It occurs in the Ig C genes of proliferating B cells.</p> Signup and view all the answers

    Which type of antigens are presented by MHC-I molecules?

    <p>Intracellular/endogenous antigens.</p> Signup and view all the answers

    Study Notes

    Physiological Barriers

    • Dolor (pain) and functio laesa (loss of function) are key symptoms of inflammatory responses.
    • Normal body temperature inhibits pathogen growth; fever response further enhances this inhibition.
    • Inflammatory cytokines play a role in raising body temperature during infection.
    • Low pH in stomach contents is effective in killing most ingested microorganisms.
    • Lysozyme found in tears, mucus, and saliva targets bacterial cell walls, causing lysis.
    • Interferons induce an antiviral state in uninfected cells, helping in immune response.
    • Neonates have a higher susceptibility to gastrointestinal infections due to less acidic gut pH compared to adults.

    Phagocytic/Endocytic Barriers

    • Endocytosis involves the uptake of cell materials; phagocytosis targets larger pathogens and whole organisms.
    • Specialized phagocytes (e.g., macrophages and neutrophils) perform ingestion, killing, and digestion of microorganisms.
    • Inflammatory response begins with damaged tissues releasing histamines, causing increased blood flow (vasodilation) and redness (erythema rubor).
    • Phagocytes utilize chemotaxis to move toward injury sites, guided by specific chemical signals.
    • Once inflammation is established, neutrophils are the first responders, followed by macrophages.
    • Fibrinogen clots block tissue spaces and lymphatics to contain the infection.

    Cytokine Network

    • The immune system distinguishes between self and non-self antigens, crucial for maintaining health and avoiding autoimmune diseases.
    • B-cells and T-cells are central to the adaptive immune response, providing lifelong immunity after initial antigen exposure.

    Antigen Processing and Presentation

    • T cells recognize foreign antigens only after they are processed into peptide fragments and presented by cells.
    • Antigens are degraded into small antigenic particles for efficient T cell recognition.
    • The Class II-associated Invariant chain Polypeptide (CLIP) assists in processing extracellular pathogens.
    • T-cells interact with MHC-II molecules through specific T-cell receptors (TCR).
    • Macrophages, dendritic cells, and B-cells act as antigen-presenting cells, expressing pattern recognition receptors.
    • Cytokines from activated T-cells enhance the functionality of antigen-presenting cells, playing a critical role in adaptive immunity.

    Immune Response and Activation

    • Co-stimulation is vital for T cell activation; lack thereof can lead to anergy (T cell unresponsiveness).
    • Cytokine storms can overwhelm T cell function, leading to dysfunction.
    • Heavy chain isotype switching improves the immune response by altering antibody functions (e.g., IgG enhances phagocyte response).

    Review Questions Insights

    • The complement pathway is integral for immune responses, leading to membrane attack complex (MAC) formation and phagocyte recruitment.
    • MHC-I presents intracellular antigens to CD8 (cytotoxic T-cells) and natural killer (NK) cells, crucial for targeting infected cells.

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    Related Documents

    Mechanisms of Immunity V2 PDF

    Description

    This quiz explores the concepts of physiological barriers in the immune system, focusing on pain, temperature, and the body's responses to pathogens. It discusses historical perspectives from figures like Galen and examines mechanisms such as fever and inflammation. Test your understanding of how these factors contribute to immunity and disease prevention.

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