Immune System Overview
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Questions and Answers

What is the primary function of antibodies?

  • Activate T cells to kill infected cells
  • Stimulate the release of histamine
  • Mark antigens for phagocytosis by macrophages (correct)
  • Destroy pathogens directly

    • What is the role of plasma cells in the immune response?

  • They produce and release antibodies (correct)
  • They directly kill infected cells
  • They act as antigen-presenting cells
  • They stimulate the production of T cells

    • Which of the following cells are directly responsible for releasing platelets into circulation?

  • Lymphocytes
  • Megakaryocytes (correct)
  • Neutrophils
  • Erythrocytes

    • What is the primary role of platelets in hemostasis?

    <p>Forming a clot at the site of injury (A)</p> Signup and view all the answers

    How does fibrin contribute to the formation of a blood clot?

    <p>It binds to platelets and red blood cells, strengthening the clot (D)</p> Signup and view all the answers

    Which of the following cells is NOT a type of leukocyte?

    <p>Erythrocyte (A)</p> Signup and view all the answers

    Which of these statements accurately describes the role of sebum in the immune system?

    <p>Sebum is an oily substance that helps maintain a healthy balance of microbes on the skin. (B)</p> Signup and view all the answers

    During diapedesis, neutrophils move through the endothelium of blood vessels. What is the driving force behind this movement?

    <p>Neutrophils are attracted to the site of infection by chemical signals called cytokines. (D)</p> Signup and view all the answers

    Which of the following statements accurately describes the role of macrophages in the immune response?

    <p>Macrophages are the first responders to infections, arriving before neutrophils. (C)</p> Signup and view all the answers

    Where do T cells mature and acquire antigen receptors?

    <p>Thymus (A)</p> Signup and view all the answers

    What is the primary role of cytotoxic T cells in the immune response?

    <p>Cytotoxic T cells directly kill infected cells through apoptosis. (A)</p> Signup and view all the answers

    Which of the following cells is NOT a professional antigen-presenting cell?

    <p>Neutrophil (D)</p> Signup and view all the answers

    What occurs when a naive T cell encounters a dendritic cell displaying an antigen that matches its receptor?

    <p>The T cell undergoes clonal expansion, producing thousands of identical T cells. (D)</p> Signup and view all the answers

    Flashcards

    T helper cell function

    Triggers B cell division and maturation in the immune response.

    B cell clonal expansion

    Process where B cells multiply to produce plasma cells and blasts after activation.

    Role of plasma cells

    Plasma cells produce and release antibodies (immunoglobulins) into the bloodstream.

    Platelet origin

    Platelets come from megakaryocytes in the bone marrow that release them into circulation.

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    Formation of a blood clot

    Platelets aggregate to form a plug, reinforced by fibrin strands to stop bleeding.

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    Sebum

    An oily fluid produced by sebaceous glands that protects skin.

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    Mucociliary clearance

    Removal of unwanted particles from lungs and trachea by cilia and mucus.

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    Diapedesis

    Process of neutrophils passing through blood vessel walls to reach tissues.

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    Neutrophils

    Type of immune cell that defends against bacterial infections.

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    T Cells

    White blood cells that recognize and respond to specific antigens.

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    Clonal expansion

    Process where activated T cells multiply to fight infections.

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    Cytotoxic T Cells

    T cells that induce cell death in infected cells.

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    B Cells

    Immune cells that produce antibodies in response to antigens.

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    Study Notes

    Immune System Protection

    • The skin provides a protective barrier against foreign substances, with sebaceous glands producing sebum, an oily fluid containing antimicrobial elements.
    • Sebum maintains a symbiotic relationship, killing harmful microbes while supporting beneficial ones.
    • Mucous membranes in the nose, mouth, and trachea have cilia that move mucus containing foreign substances upwards.
    • Mucociliary clearance removes unwanted particles from the lungs and trachea via coughing and exhaling.
    • Bone marrow contains stem cells that differentiate into daughter cells—either stem cells or progenitor cells—forming various immune cells (leukocytes), including neutrophils.
    • Neutrophils, part of the innate immune system, traverse blood vessels during inflammation.
    • Diapedesis is the process of neutrophils passing through blood vessel endothelium, aided by chemotaxis, following cytokines released by other cells.
    • Neutrophils phagocytose bacteria and release cytokines, attracting other granulocytes and macrophages.
    • Macrophages arrive before neutrophils, phagocytizing bacteria and producing tumor necrosis factor, a signal suppressing hunger, inducing fever, and stimulating leukocyte production.

    T Cells and Immune Response

    • T cells recognize antigens presented by macrophages or antigen-presenting cells.
    • T cells mature in the thymus, acquiring antigen receptors.
    • Naive T cells encounter dendritic cells in secondary lymphoid organs (lymph nodes and spleen).
    • Dendritic cells display antigens, triggering T cell activation if the antigen matches the T cell receptor.
    • Activated T cells undergo clonal expansion, producing many antigen-specific cells.
    • Cytotoxic T cells identify and induce apoptosis in infected cells.
    • Helper T cells collaborate with B cells.

    B Cells and Antibody Production

    • B cells originate in bone marrow, seeking specific antigens.
    • Upon antigen recognition, B cells activate or migrate to lymphoid tissue to encounter helper T cells.
    • B cells present antigens for T helper cell recognition.
    • T helper cell recognition triggers B cell division and maturation.
    • B cells expand clonally, producing plasma blasts and plasma cells.
    • Plasma blasts and plasma cells release antibodies (immunoglobulins) into the bloodstream.
    • Antibodies bind to toxins, antigens, and pathogens, inactivating toxins and marking antigens for macrophage phagocytosis (opsonization).

    Platelets and Hemostasis

    • Platelets (thrombocytes) develop from megakaryocytes in the bone marrow.
    • Megakaryocytes release platelets into circulation via pseudopodia.
    • Platelets circulate and adhere to collagen fibers after blood vessel injury.
    • Platelets aggregate, forming a fragile platelet plug.
    • Fibrin strands strengthen the plug, binding platelets and red blood cells, creating a stable clot.

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    Description

    Explore the essential components and functions of the immune system in this quiz. Learn about the protective roles of the skin, mucous membranes, and the actions of neutrophils in response to inflammation. Test your knowledge on how these elements work together to defend against foreign substances.

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