Immunology: The Immune System
74 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary role of leukocytes?

  • To produce and educate immune cells
  • To function as a physical barrier
  • To defend the body against microorganisms that cause infection and remove debris (correct)
  • To screen the lymph and bloodstream

    • Which type of leukocyte has an irregular, multilobulated nucleus?

  • Eosinophils
  • Neutrophils
  • Monocytes
  • Basophils (correct)

    • What is the function of the spleen in the immune system?

  • To screen the bloodstream (correct)
  • To function as a physical barrier
  • To produce immune cells
  • To screen the lymph

    • What is the primary difference between granulocytes and agranulocytes?

    <p>Granulocytes have many membrane-bound granules, while agranulocytes have fewer</p> Signup and view all the answers

    What is the role of the thymus in the immune system?

    <p>To educate immune cells</p> Signup and view all the answers

    What is the function of lymph nodes in the immune system?

    <p>To screen the lymph</p> Signup and view all the answers

    What is the primary function of cytotoxic T cells in adaptive immunity?

    <p>To destroy infected cells</p> Signup and view all the answers

    Where do T cells differentiate and mature in the adaptive immune system?

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

    What is the main role of humoral immunity in adaptive immunity?

    <p>To defend against extracellular microbes using antibodies</p> Signup and view all the answers

    How do lymphocytes ensure self-tolerance during their development?

    <p>By destroying cells that bind to 'self' antigens</p> Signup and view all the answers

    What is the primary function of helper T cells in adaptive immunity?

    <p>To regulate the immune response by amplifying it</p> Signup and view all the answers

    What is the site where lymphocytes are exposed to 'non-self' antigens and become activated?

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

    What is the primary function of neutrophils in the innate immune response?

    <p>To engulf and eliminate pathogens through phagocytosis</p> Signup and view all the answers

    Which of the following cell types is responsible for antibody creation in the adaptive immune response?

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

    What is the role of pattern recognition receptors (PRRs) on the surface of innate immune cells?

    <p>To recognize and respond to pathogen-associated molecular patterns</p> Signup and view all the answers

    What is the primary function of the complement system in the immune response?

    <p>To contribute to the inflammatory response</p> Signup and view all the answers

    What is the role of cytokines in the immune response?

    <p>To allow communication between immune cells</p> Signup and view all the answers

    Which of the following is an example of a biochemical barrier in the innate immune response?

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

    What is the primary function of dendritic cells in the immune response?

    <p>To present antigens to T-cells in lymph nodes</p> Signup and view all the answers

    What is the role of histamine in the immune response?

    <p>To contribute to the inflammatory response</p> Signup and view all the answers

    What is the primary function of eosinophils in the immune response?

    <p>To defend against parasitic worms</p> Signup and view all the answers

    What is the role of MHC molecules in the immune response?

    <p>To distinguish between self and non-self molecules</p> Signup and view all the answers

    What is the primary function of cytotoxic T-cells?

    <p>To kill infected or cancerous cells</p> Signup and view all the answers

    What is required for the activation of helper T-cells?

    <p>Binding of antigen to MHC II and stimulation by IL-1 and TNF</p> Signup and view all the answers

    What is the primary role of natural killer cells?

    <p>To recognize and destroy infected or cancerous cells</p> Signup and view all the answers

    What is the primary function of immune memory?

    <p>To maintain a small number of primed cells for future infections</p> Signup and view all the answers

    What is the primary difference between the primary and secondary immune responses?

    <p>The speed and magnitude of the response</p> Signup and view all the answers

    What is the primary function of memory B-cells?

    <p>To travel and stimulate an immune response upon pathogen detection</p> Signup and view all the answers

    What is the primary type of antibody produced during the primary immune response?

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

    What is the primary characteristic of passive immunity?

    <p>No memory cell production</p> Signup and view all the answers

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

    <p>To activate other immune cells, including cytotoxic T-cells and B-cells</p> Signup and view all the answers

    What is the primary difference between IgM and IgG antibodies?

    <p>The duration of protection they provide</p> Signup and view all the answers

    What is the primary function of antibodies produced by B-cells?

    <p>To facilitate destruction of pathogens through various mechanisms</p> Signup and view all the answers

    Which type of T-cells is responsible for attacking and destroying infected cells or enemy cells?

    <p>Cytotoxic T-cells (CD8+)</p> Signup and view all the answers

    What is the role of IgM antibodies in the adaptive immune response?

    <p>Providing early, high-affinity response to eliminate pathogens</p> Signup and view all the answers

    What is the primary function of Class I MHC molecules?

    <p>Presenting endogenous antigens to T-cells</p> Signup and view all the answers

    Which type of cells are known as professional antigen-presenting cells (APCs)?

    <p>Macrophages, dendritic cells, activated B cells, activated T cells, and thymus cells</p> Signup and view all the answers

    What is the primary difference between IgG and IgM antibodies?

    <p>IgG provides long-lasting immunity, while IgM provides early response</p> Signup and view all the answers

    What is the role of IgE antibodies in the immune response?

    <p>Triggering histamine release from mast cells</p> Signup and view all the answers

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

    <p>Giving specificity to the antigen-binding site</p> Signup and view all the answers

    Which type of T-cells is responsible for amplifying T-cell and B-cell activity against a specific antigen?

    <p>Helper T-cells (CD4+)</p> Signup and view all the answers

    What is the primary function of MHC molecules in the immune response?

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

    What is the primary function of PRRs in the immune response?

    <p>To recognize and bind to pathogen-associated molecular patterns</p> Signup and view all the answers

    During an acute inflammatory response, what occurs in the affected area?

    <p>Vasodilation and increased capillary permeability</p> Signup and view all the answers

    What is the role of lysosomes in phagocytosis?

    <p>To fuse with phagocytic vacuoles and kill microorganisms</p> Signup and view all the answers

    What is the primary function of the complement system?

    <p>To form a membrane attack complex, lysing invading bacteria</p> Signup and view all the answers

    What is the primary characteristic of adaptive immunity?

    <p>Specific recognition of pathogens and memory</p> Signup and view all the answers

    What is the final phase of inflammation?

    <p>Tissue repair and remodeling</p> Signup and view all the answers

    What is the primary function of neutrophils during inflammation?

    <p>To phagocytose and eliminate bacteria</p> Signup and view all the answers

    What is the role of marginating neutrophils?

    <p>To roll along vessel walls, detecting non-self particles or inflammatory mediators</p> Signup and view all the answers

    What is the consequence of taking steroids on WBC count?

    <p>An increase in WBC count</p> Signup and view all the answers

    What is the primary function of plasma protein synthesis during inflammation?

    <p>To produce acute phase reactants, which can be pro-inflammatory or anti-inflammatory</p> Signup and view all the answers

    What is the primary function of vaccination?

    <p>To introduce a microorganism or its antigens in a form not expected to cause disease, inducing an immune response including production of memory cells</p> Signup and view all the answers

    What is the primary difference between active and passive immunity?

    <p>Active immunity involves the production of memory cells, while passive immunity does not</p> Signup and view all the answers

    What is the function of the Hepatitis B surface antigen in the Hepatitis B vaccine?

    <p>It is a protein component of the Hep B virus that induces an antibody response</p> Signup and view all the answers

    What is the primary function of IgM antibodies in the immune response?

    <p>To neutralize pathogens in the early stages of an infection</p> Signup and view all the answers

    What is the primary reason why booster doses are needed?

    <p>To maintain immunity to a disease over time</p> Signup and view all the answers

    What is the primary difference between IgM and IgG antibodies?

    <p>IgM is produced in the primary response, while IgG is produced in the secondary response</p> Signup and view all the answers

    What is the primary mechanism by which transfusion reactions occur?

    <p>Antibodies produced by B cells bind to plasma membrane proteins, recognizing them as 'non-self'</p> Signup and view all the answers

    What is the most common antigen responsible for Rh isoimmunization?

    <p>Rh D antigen</p> Signup and view all the answers

    What type of immune response do vaccines stimulate?

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

    What is the primary consequence of Rh isoimmunization in an Rh-negative mother carrying an Rh-positive fetus?

    <p>Fetal hemolysis and neonatal kernicterus</p> Signup and view all the answers

    What is the primary function of anti-HBs IgG antibodies in hepatitis B infection?

    <p>To provide long-term immunity</p> Signup and view all the answers

    What is the role of macrophages in transfusion reactions?

    <p>Engulfing and destroying RBCs</p> Signup and view all the answers

    What is the primary mechanism of immune tolerance development during fetal and early postnatal life?

    <p>Clonal deletion or clonal inactivation</p> Signup and view all the answers

    What is the universal recipient blood type?

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

    What is the primary characteristic of autoimmune diseases?

    <p>An immune response against self-antigens</p> Signup and view all the answers

    What is the typical outcome of a transfusion reaction in a patient with type A blood receiving a transfusion of B blood?

    <p>A severe transfusion reaction</p> Signup and view all the answers

    What is the primary function of cytotoxic T cells in an autoimmune response?

    <p>To attack and kill healthy host cells</p> Signup and view all the answers

    What is the primary function of helper T cells in HIV infection?

    <p>To activate cytotoxic T cells</p> Signup and view all the answers

    What is the primary mechanism of HIV transmission to a new host?

    <p>Through viral load in body fluids</p> Signup and view all the answers

    What is the primary characteristic of transfusion reactions?

    <p>Destruction of erythrocytes</p> Signup and view all the answers

    What is the primary function of the immune system in autoimmune diseases?

    <p>To attack healthy host cells</p> Signup and view all the answers

    What is the primary mechanism of immune tolerance in pregnancy?

    <p>Dampening of the immune system</p> Signup and view all the answers

    Study Notes

    The Immune System

    • Functions:
      • Physical barrier
      • Production and "education" of immune cells
      • Defense against microorganisms and removal of debris
    • Organs and cells involved:
      • Bone marrow
      • Thymus
      • Spleen (screens bloodstream)
      • Lymph nodes (screen lymph)
      • Lymphoid organs (screen border regions)
      • Leukocytes (classify into granulocytes and agranulocytes)

    Cells of the Immune System

    Leukocytes

    • Defend the body against microorganisms and remove debris
    • Classified according to structure:
      • Granulocytes (many membrane-bound granules in cytoplasm)
        • Neutrophils
        • Eosinophils
        • Basophils
      • Agranulocytes (fewer granules in cytoplasm)
        • Monocytes
        • Macrophages
        • Lymphocytes

    Immune Response

    Innate Immunity (Natural Immunity)

    • First response to infection
    • Early defense systems of the body:
      • Epithelial barrier
      • Inflammation
    • Cells involved:
      • Neutrophils
      • Eosinophils
      • Basophils
      • Monocytes/macrophages
      • Dendritic cells

    Adaptive Immunity (Acquired Immunity)

    • Second response to infection
    • Long-term and highly effective immunity
    • Cells involved:
      • B cells (antibody creation)
      • T cells (CD4+ and CD8+)
      • Cytokines and chemokines (communication between cells)

    Molecules of the Immune System

    • Broad categories:
      • Antigens (non-self molecules detected by the immune system)
      • MHC (major histocompatibility complex) molecules (self proteins used to detect non-self molecules)
      • Antibodies (effector molecules)
      • Cytokines and chemokines (messenger molecules)

    The Body's Lines of Defense

    • Innate immunity:
      • Physical barrier
      • Mechanical barrier
      • Biochemical barrier
      • Normal microbiome
    • Adaptive immunity:
      • Specificity and memory

    Inflammation

    • Response to tissue injury or infection
    • Cells involved:
      • Macrophages
      • Neutrophils
      • Eosinophils
      • Dendritic cells
    • Functions:
      • Prevent infection spread
      • Promote healing
      • Activate immune cells

    Immune System Plasticity

    • Ability of the immune system to undergo changes in response to a physiologic environment
    • Adaptive immunity:
      • Encounter
      • Activation
      • Antibody creation
      • Attack

    Lymphoid Tissue

    • Primary lymphoid organs:
      • Bone marrow
      • Thymus
    • Secondary lymphoid organs:
      • Spleen
      • Lymph nodes
      • Tonsils
      • Adenoids
      • Appendix
      • Peyer's patches

    Lymphocyte Differentiation

    • Starts in bone marrow with a pluripotent stem cell
    • Further differentiates into:
      • Myeloid stem cells
      • Lymphoid stem cells
      • T cells
      • B cells

    Adaptive Immunity Cell Functions

    • B cells:
      • Mature into plasma cells
      • Produce antibodies
    • T cells:
      • Cytotoxic T cells (CD8+): kill infected cells
      • Helper T cells (CD4+): regulate immune response
      • Regulatory T cells: suppress or limit immune response

    Antibodies

    • Functions:
      • Neutralize antigens
      • Agglutinate antigens
      • Opsonize antigens
      • Activate complement cascade
      • Enhance natural killer cell activity
    • Five classes of antibodies:
      • IgG
      • IgM
      • IgA
      • IgE
      • IgD

    T Cells

    • Functions:
      • Find antigens presented on MHC molecules
      • Attack and destroy infected cells
      • Amplify immune response
    • MHC molecules:
      • Class I: present endogenous antigens
      • Class II: present exogenous antigens
      • Professional antigen-presenting cells (APCs): macrophages, dendritic cells, activated B cells, activated T cells, and thymus cells
      • Non-professional APCs: all nucleated cells

    Immunity

    • Passive immunity has two forms: administration of synthetically produced antibodies and transfer of antibodies from mother to fetus or baby through the placenta (IgG) and breast milk (IgA)
    • Passive immunity does not produce memory cells, so there is no long-term immunity

    Active Immunity

    • An immune response to a vaccine or pathogen in an individual
    • Confers immunity due to the production of memory cells
    • Vaccination introduces a microorganism or its antigens in a form not expected to cause disease, inducing an immune response and production of memory cells

    Immunologic Memory

    • Immunization provides protection from infection due to controlled exposure to either killed or disabled pathogen
    • Allows adaptive immune system to form antibodies and train memory B and T cells specific for pathogens
    • If the vaccinated patient encounters the pathogen, previously formed antibodies and memory cells prevent disease by quickly neutralizing the pathogen

    Hepatitis B Vaccine

    • Uses surface protein (Hep B surface antigen or HBsAg)
    • A vaccinated person creates antibodies to HBsAg – called Anti HBs
    • IgM emerges first, followed by IgG
    • Once IgG is established, the person is immune to Hep B – unless IgG titers go down, requiring a booster dose

    Hep B Disease and Immunity

    • Someone who has been infected with Hepatitis antigen will first make IgM to the HBcAg and HBsAg
    • As they move into making IgG for these, immunity has developed
    • Anti-HBs IgG is the last step towards completely eradicating a Hepatitis B infection
    • Some people never make this, and thus become chronic carriers of hepatitis B

    Immune Response

    • Antigen gets past physical barriers and into lymphatics
    • Antigen gets exposed to B cells and macrophages in the spleen or a lymph node
    • Macrophages eat the invaders and present them to T cells using the MHC, releasing cytokines like IL-1 and TNF
    • Helper T cells are activated and make IL-2, creating a giant colony of helper-T cells against the invader
    • Helper T cells release B-cell-activating cytokines, causing B cells to proliferate and become either plasma cells or memory B cells
    • Antibodies made by B cells opsonize the invader for ingestion, clump invaders together, and cover the invader's binding sites

    Immune Tolerance

    • Develops during fetal and early postnatal life due to clonal deletion or clonal inactivation
    • Pregnant mothers have a dampened immune system to "tolerate" the "non-self" of the developing embryo
    • Autoimmune diseases are caused by failure in development of self-tolerance

    Autoimmunity

    • An immune response by the host against the host, or inflammation in the absence of infection
    • Cytotoxic T-cells may attack and kill healthy host cells
    • Helper T cells may promote inflammation where none is needed
    • B cells may produce antibodies that bind self structures
    • Under normal conditions, self-reactive cells undergo apoptosis or are silenced

    Immunodeficiency Diseases

    • Result from weak or under-active immune systems
    • Examples: SCID, Hodgkin's Disease, AIDS
    • HIV affects helper T cells
    • Human Immunodeficiency virus (HIV) is a retrovirus made of double-stranded RNA that targets cells expressing CD4 receptors (helper T cells, some macrophages, some monocytes)

    Transfusion Reactions

    • Definition: Illness caused when erythrocytes are destroyed during blood transfusion
    • Key Facts: Erythrocytes do not have MHC proteins but have plasma membrane proteins and carbohydrates that can function as antigens
    • Transfusion reactions happen when antibodies bind to these plasma membrane proteins/carbohydrates, recognizing them as "non-self"
    • The RBC's are then engulfed/destroyed by macrophages, triggering the MHC Class II Helper T cell response
    • The ABO system of carbohydrates is the most important for transfusion reactions
    • Rh proteins are next most important
    • O negative is the universal donor
    • AB is the universal recipient
    • If someone with type A blood is given a transfusion of B blood, a transfusion reaction occurs
    • Symptoms of transfusion reaction include itchiness, hemolysis, allergy, and alloimmunization

    Alloimmunization

    • An immunologic disorder that occurs in an Rh- negative patient carrying an Rh- positive fetus
    • Rh complex is made up of lots of antigens, including C, D, E, c, and e
    • More than 90% of cases of Rh Isoimmunization are due to D antibodies
    • Maternal immune system makes IgM and then IgG to Rh antigen
    • Antibodies cross the placenta and cause hemolysis of fetal red blood cells
    • Can lead to profound anemia, fetal hydrops, intrauterine fetal death, high bilirubin leading to neonatal kernicterus

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Learn about the functions and components of the immune system, including physical barriers, immune cells, and lymphoid organs. Discover how the immune system defends the body against microorganisms and infection.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser