Immunology: T Cells, B Cells, and Innate Immunity
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Questions and Answers

What is the primary function of T cells?

  • To carry oxygen in the blood
  • To manage the immune response and destroy foreign cells (correct)
  • To enhance the production of macrophages
  • To produce antibodies

    • Which of the following accurately describes the role of B cells?

  • They produce plasma cells that secrete antibodies. (correct)
  • They phagocytize foreign substances.
  • They capture antigens and present them to T cells.
  • They support other cell types in lymphoid organs.

    • Identify a primary lymphatic organ.

  • Thymus (correct)
  • Lymphatic nodules
  • Lymph nodes
  • Spleen

    • What is the function of dendritic cells in the immune system?

    <p>To capture antigens and present them to lymph nodes</p> Signup and view all the answers

    What do macrophages primarily do within the immune system?

    <p>Phagocytize foreign substances</p> Signup and view all the answers

    What characterizes lymphatic nodules?

    <p>They are often small and solitary.</p> Signup and view all the answers

    Which of the following is NOT a physical barrier of innate immunity?

    <p>Sebaceous glands</p> Signup and view all the answers

    Which function does mucus serve in innate immunity?

    <p>Traps microbes and foreign substances.</p> Signup and view all the answers

    What role do interferons play in the second line of defenses?

    <p>They prevent the replication of viruses in neighboring cells.</p> Signup and view all the answers

    Which of the following statements about mucosa-associated lymphatic tissue (MALT) is correct?

    <p>It includes tonsils and Peyer’s patches.</p> Signup and view all the answers

    What is the primary function of the lacrimal apparatus in innate immunity?

    <p>Washing action of tears to remove pathogens.</p> Signup and view all the answers

    Which of the following substances is known for breaking down bacterial cell walls?

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

    Which characteristic of innate immunity is depicted in the phrase 'first line of defenses'?

    <p>It includes external physical and chemical barriers.</p> Signup and view all the answers

    What is the primary role of neutrophils in the early stages of an immune response?

    <p>To emigrate to damaged tissues and perform phagocytosis</p> Signup and view all the answers

    Which statement about monocytes is accurate?

    <p>They have a longer lifespan than neutrophils.</p> Signup and view all the answers

    What defines adaptive immunity?

    <p>Ability to respond to specific invading agents with memory.</p> Signup and view all the answers

    Where do B cells complete their development?

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

    What type of pathogens are cytotoxic T cells particularly effective against?

    <p>Intracellular pathogens such as viruses</p> Signup and view all the answers

    The process by which B cells transform into plasma cells that produce antibodies is known as?

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

    What are helper T cells classified as?

    <p>CD4 T cells</p> Signup and view all the answers

    What is pus composed of?

    <p>Dead phagocytes and damaged tissue</p> Signup and view all the answers

    What is the main purpose of clonal selection in the immune response?

    <p>To proliferate and differentiate lymphocytes in response to a specific antigen</p> Signup and view all the answers

    What occurs during the initial immune response after clonal selection?

    <p>Effector cells such as active helper T cells and plasma cells are generated</p> Signup and view all the answers

    Which characteristic defines an effective antigen?

    <p>Ability to provoke immune response and react specifically with antibodies</p> Signup and view all the answers

    What is an epitope?

    <p>A small part of the antigen recognized by the immune system</p> Signup and view all the answers

    What happens to memory cells after they are produced?

    <p>They respond to a second invasion by proliferating and differentiating</p> Signup and view all the answers

    What is the primary role of complement proteins in the immune response?

    <p>Promote inflammation and cytolysis</p> Signup and view all the answers

    What role do Major Histocompatibility Complex (MHC) Antigens play in the immune response?

    <p>They help T cells recognize foreign or self antigens</p> Signup and view all the answers

    Which of the following iron-binding proteins is NOT involved in transporting iron in the blood?

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

    During clonal selection, effector cells are responsible for what?

    <p>Inactivating the antigen</p> Signup and view all the answers

    What is the main function of antimicrobial proteins (AMPs)?

    <p>Exhibit broad-spectrum antimicrobial activity</p> Signup and view all the answers

    Swollen lymph nodes and tonsils are indicators of what process?

    <p>Initial immune response and clonal selection occurring</p> Signup and view all the answers

    Which statement best describes Natural Killer (NK) cells?

    <p>They attack cells displaying abnormal membrane proteins.</p> Signup and view all the answers

    What is the first step of phagocytosis?

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

    Which of the following is NOT a sign or symptom of inflammation?

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

    What occurs during the vasodilation phase of inflammation?

    <p>Blood vessels increase in diameter to allow more blood flow.</p> Signup and view all the answers

    Which cell type is primarily responsible for phagocytosis?

    <p>Neutrophils and macrophages</p> Signup and view all the answers

    What is the role of histamine during inflammation?

    <p>Causes increased blood vessel permeability.</p> Signup and view all the answers

    Which of the following steps is NOT part of the phagocytosis process?

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

    Which type of antigens can be presented by antigen-presenting cells (APCs) using MHC-II molecules?

    <p>Exogenous antigens</p> Signup and view all the answers

    What is the role of costimulation in T cell activation?

    <p>It prevents accidental activation of T cells.</p> Signup and view all the answers

    CD4 proteins are primarily associated with which type of T cells?

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

    What do cytotoxic T cells primarily target?

    <p>Infected body cells</p> Signup and view all the answers

    What is the primary function of antibodies?

    <p>To bind and neutralize specific antigens</p> Signup and view all the answers

    Which cells are considered antigen-presenting cells (APCs)?

    <p>Dendritic cells, macrophages, and B cells</p> Signup and view all the answers

    What happens to a helper T cell after it is activated?

    <p>It undergoes clonal selection and produces active and memory cells.</p> Signup and view all the answers

    Which of the following correctly describes the structure of antibodies?

    <p>Composed of heavy and light chains with a variable region</p> Signup and view all the answers

    How do cytotoxic T cells kill infected cells?

    <p>By releasing perforin and granzymes</p> Signup and view all the answers

    What is the primary purpose of the variable region of an antibody?

    <p>To bind specifically to an antigen</p> Signup and view all the answers

    What occurs during the endocytosis of exogenous antigens by an APC?

    <p>Antigens are ingested and processed into peptide fragments.</p> Signup and view all the answers

    What is the significance of memory B cells in immunity?

    <p>They remain inactive until the same antigen appears again.</p> Signup and view all the answers

    Which statement best describes the relationship between MHC molecules and their antigen presentation?

    <p>MHC-II is primarily involved in presenting exogenous antigens to T cells.</p> Signup and view all the answers

    What defines the role of the hinge region in an antibody structure?

    <p>It allows for flexibility in the antibody's structure.</p> Signup and view all the answers

    Study Notes

    Lymphatic System Overview

    • The lymphatic system is a network of vessels, tissues, and organs that plays a crucial role in immunity and fluid balance.
    • It comprises lymphatic vessels, lymph nodes, organs (thymus, spleen, tonsils, etc), plus red bone marrow.
    • Functions of the lymphatic system include draining excess interstitial fluid, transporting dietary lipids, and carrying out immune responses.

    Immunity or Resistance

    • Immunity or resistance is the ability to ward off damage or disease through our defenses.
    • 2 types of immunity, innate (nonspecific) and adaptive (specific).
    • Innate immunity is present at birth and has no specific recognition of invaders, but does have a 1st and 2nd line of defenses.
    • Adaptive immunity has specific recognition of pathogens with a memory component.

    Lymphatic System Structure and Function

    • The lymphatic system comprises lymph, lymphatic vessels, and structures/organs with lymphatic tissue, and red bone marrow.
    • The lymphatic fluid, lymph, is comprised of excess interstitial fluid and travels through lymphatic vessels.
    • The lymphatic vessels resemble veins but have thinner walls and more valves; they move the lymph unidirectionally toward the venous circulation.
    • Lymph flows through lymph nodes before returning to the venous system.

    Lymphatic Vessels and Lymph Circulation

    • Lymphatic vessels begin as lymphatic capillaries
    • These capillaries are closed at one end and unite to form larger lymphatic vessels.
    • Lymphatic vessels resemble veins in structure, but have thinner walls and more valves.
    • Lymphatic vessels pass through lymph nodes.

    Lymphatic Capillaries

    • Lymphatic capillaries are slightly larger in diameter than blood capillaries.
    • They're characterized by a unique one-way structure.
    • Interstitial fluid flows into lymphatic capillaries but cannot flow back out.
    • Anchoring filaments allow for wider openings when interstitial fluid accumulates.

    Lymph Trunks and Ducts

    • Lymphatic vessels unite to form lymph trunks.
    • Principal trunks are lumbar, intestinal, bronchomediastinal, subclavian, and jugular.
    • Lymph from these trunks enters in 2 main channels: thoracic and right lymphatic duct.
    • The lymph eventually drains into the venous circulation.

    Primary Lymphatic Organs

    • These are sites where stem cells divide and differentiate.
    • They include red bone marrow and thymus.

    Secondary Lymphatic Organs

    • These are sites where most immune responses occur.
    • These organs include lymph nodes, spleen, and lymphatic nodules.

    Lymphoid Organs - Location and Description

    • Tonsils (pharyngeal region)
    • Thymus (thorax; active in youth)
    • Spleen (curves around left side of stomach)
    • Peyer's patches (intestinal)
    • Appendix

    Thymus

    • Internal anatomy: thymic lobes have an outer cortex and inner medulla.
    • The cortex has densely packed lymphocytes and scattered macrophages, while the medulla has fewer lymphocytes and thymic (Hassall's) corpuscles.
    • The thymus differs from other lymphoid organs in that it functions solely for T lymphocyte maturation.
    • The thymus stroma consists of star-shaped epithelial cells, not reticular fibers.

    Lymph Nodes - Structure and Function

    • Lymph nodes are located along lymphatic vessels, scattered throughout the body.
    • Nodes have a fibrous capsule and trabeculae that divide them into compartments.
    • Lymph nodes contain a cortex and medulla.
    • The lymph nodes filter lymph and are sites of immune response.

    Spleen

    • The spleen is the body's largest lymphoid organ.
    • The spleen has a capsule, trabeculae, reticular fibers, and fibroblasts (stroma).
    • Parenchyma includes white pulp (lymphocytes and macrophages), where B and T cells perform their function, and red pulp, blood-filled venous sinuses and cords, and macrophages remove worn-out blood cells.

    Lymphatic Nodules

    • Lymphatic nodules are not encapsulated.
    • They're scattered throughout the lamina propria of mucous membranes in the GI, urinary, and reproductive tracts.
    • Mucosa-associated lymphatic tissue (MALT) is found in the respiratory tract.
    • Various lymphatic nodules include tonsils, Peyer's patches, and appendix.

    Lymphatic System Summary

    • The lymphatic system is part of the body's defense mechanism.
    • The system provides drainage of excess interstitial fluid and transport of fatty acids and immune responses.

    Innate Immunity

    • Skin and mucous membranes form a 1st line of defense, acting as both physical and chemical barriers.
    • Internal defenses (2nd line of defense) include phagocytic leukocytes, antimicrobial proteins, and inflammatory responses.

    Adaptive Immunity

    • Adaptive immunity is the body's ability to defend itself against specific invading agents.
    • Antigens are molecules that trigger adaptive immune responses.
    • Adaptive immunity can be divided into cell-mediated and antibody-mediated responses.
    • Cells of adaptive immunity include T and B cells.

    Antigen Processing and Presentation

    • B cells and T cells only recognize fragments of antigens, meaning that antigens must be processed before they can be recognized.
    • APC's process exogenous and endogenous antigens in different pathways depending on whether the antigens are located outside or inside cells.

    Cell-mediated Immunity

    • Activation, clonal selection, and elimination of invaders are characteristics of cell-mediated immunity.
    • T cells (cytotoxic T cells) have the capability to attack infected cells.

    Antibody-mediated Immunity

    • B cells differentiate into plasma cells and release antibodies.
    • Antibodies circulate in body fluids, rendering pathogens inactive.

    Immunological Memory

    • Memory cells are produced when the body encounters an antigen.
    • This memory allows the body to respond faster and more strongly upon subsequent encounters with the same antigen.

    Self-Recognition and Self-Tolerance

    • T cells self-recognize and differentiate recognizing and destroying self-molecules
    • Self-tolerance prevents the immune system from attacking its own tissues.

    Additional Details

    • The summary has covered a range of aspects including structures, functions, antigen, and immunity.

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    Lymphatic System Notes PDF

    Description

    Test your knowledge on the immune system with questions focusing on T cells, B cells, and the role of various immune cells in both innate and adaptive immunity. This quiz covers essential functions, characteristics, and mechanisms in immunology, providing a comprehensive review for students and enthusiasts alike.

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