Introduction to Immunology
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Questions and Answers

What is the primary function of the immune system?

  • To produce hormones for growth
  • To regulate body temperature
  • To facilitate nutrient absorption
  • To prevent or eradicate infections (correct)

    • Which type of lymphocytes are derived from the bone marrow?

  • Eosinophils
  • T lymphocytes
  • Basophils
  • B lymphocytes (correct)

    • What role do basophils play in the immune system?

  • Engulfing microorganisms
  • Secreting histamine during allergic reactions (correct)
  • Producing antibodies
  • Transferring oxygen to tissues

    • Which of the following cells is known for being one of the first to respond to infections?

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

    What defines the term 'immunity' in the context of immunology?

    <p>Resistance to infectious disease</p> Signup and view all the answers

    Eosinophils are primarily associated with which type of responses?

    <p>Allergic reactions and helminth infections</p> Signup and view all the answers

    What characterizes an immune response?

    <p>A coordinated reaction of cells and molecules to infectious agents</p> Signup and view all the answers

    Which cell type contains granules that secrete substances like heparin and histamine?

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

    What role do NK cells primarily play in the immune system?

    <p>They provide innate cytotoxicity against tumor cells.</p> Signup and view all the answers

    Which type of leukocyte is characterized by the presence of granules in their cytoplasm?

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

    Where in the body are Antigen Presenting Cells (APCs) primarily located?

    <p>In skin, lymph nodes, thymus, and mucosal epithelia</p> Signup and view all the answers

    Which of the following is NOT a function of NK cells?

    <p>Producing antibodies against pathogens</p> Signup and view all the answers

    Which of the following leukocytes have a long lifespan and can live for months?

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

    What is the primary function of interdigitating dendritic cells?

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

    In which area of the lymph nodes are B cells primarily found?

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

    Which type of granulocyte is primarily involved in combating parasitic infections?

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

    What is the primary role of dendritic cells in the immune system?

    <p>To activate immune responses by presenting antigens.</p> Signup and view all the answers

    Which of the following cells is classified as a phagocyte?

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

    What distinguishes primary lymphoid tissue from secondary lymphoid tissue?

    <p>Primary lymphoid tissue is where lymphocytes mature, while secondary lymphoid tissue is where they exert their functions.</p> Signup and view all the answers

    Which of the following statements about T cells is incorrect?

    <p>Pre-T lymphocytes migrate to the spleen for maturation.</p> Signup and view all the answers

    What is the primary function of mast cells within the immune system?

    <p>To stimulate inflammation through the release of chemicals.</p> Signup and view all the answers

    Which cellular component is primarily involved in the immediate immune response?

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

    How do T Helper cells assist in the immune response?

    <p>By stimulating B cells to produce antibodies.</p> Signup and view all the answers

    Which statement accurately describes the spleen's role in the immune system?

    <p>It acts as a filtration organ for pathogens and dead cells.</p> Signup and view all the answers

    Neutrophils are known for being the first immune cells to travel to the site of an infection.

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

    Eosinophils are primarily involved in initiating and propagating inflammatory responses associated with bacterial infections.

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

    The immune system consists of only innate immunity mechanisms which respond to infections.

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

    Basophils are a type of leukocyte that primarily secrete substances such as heparin and histamine.

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

    Lymphocytes can be divided into B lymphocytes, which are derived from the thymus, and T lymphocytes, which are derived from the bone marrow.

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

    The term 'immunity' refers to the body’s resistance specifically to infectious diseases.

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

    The immune response comprises only the actions of T lymphocytes and does not involve other types of immune cells.

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

    Granulocytes are characterized by the presence of granules in their cytoplasm and include basophils and eosinophils.

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

    NK cells are primarily involved in the adaptive immune response.

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

    Agranulocytes are characterized by the presence of granules in their cytoplasm.

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

    Antigen Presenting Cells (APCs) are primarily found in the skin, lymph nodes, and mucosal epithelia.

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

    Eosinophils have a long lifespan and can live for several months.

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

    Monocytes are classified as granulocytes.

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

    Dendritic cells can present antigens to both T cells and B cells.

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

    Neutrophils are known for their role in combating viral infections primarily.

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

    The primary function of NK cells is to release perforin to lyse infected cells.

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

    Dendritic cells are primarily found in connective tissue and activate inflammation by releasing histamine.

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

    T Helper cells, identified by CD4+, play a crucial role in stimulating B cells to produce antibodies.

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

    The spleen is classified as a primary lymphoid tissue where lymphocytes mature.

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

    Macrophages function by surrounding and killing microorganisms while also stimulating other immune system cells.

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

    Mast cells are found primarily in the lymph nodes and are not involved in inflammatory responses.

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

    Pre-T lymphocytes must travel to the thymus gland for differentiation and maturation.

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

    B cells differentiate in the thymus gland and are primarily involved in the cell-mediated immune response.

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

    Secondary lymphoid tissues are where lymphocytes proliferate and mature.

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

    What are the two distinct types of immunity defined in immunology?

    <p>Innate (natural) immunity and adaptive (acquired) immunity.</p> Signup and view all the answers

    Identify the role of neutrophils in the immune response.

    <p>Neutrophils help fight infection by ingesting microorganisms and releasing enzymes that kill them.</p> Signup and view all the answers

    What defines the term 'immune response' in the context of immunology?

    <p>An immune response is the coordinated reaction of immune cells and molecules to infectious microbes.</p> Signup and view all the answers

    Explain the significance of lymphocytes in the immune system.

    <p>Lymphocytes express antigen receptors to recognize specific antigens, facilitating targeted immune responses.</p> Signup and view all the answers

    How do eosinophils contribute to the immune system, particularly in allergic reactions?

    <p>Eosinophils are associated with the initiation and propagation of inflammatory responses, particularly in allergic disease.</p> Signup and view all the answers

    What substances do basophils release to mediate allergic inflammation?

    <p>Basophils release substances such as heparin and histamine.</p> Signup and view all the answers

    Distinguish between B lymphocytes and T lymphocytes in terms of their origin and primary function.

    <p>B lymphocytes are derived from bone marrow and primarily produce antibodies, while T lymphocytes are derived from the thymus and are involved in cell-mediated immunity.</p> Signup and view all the answers

    Describe the primary physiological function of the immune system.

    <p>The primary function of the immune system is to prevent or eradicate infections caused by viruses, bacteria, fungi, and parasites.</p> Signup and view all the answers

    What is the function of mast cells in the immune response?

    <p>Mast cells activate inflammation by releasing chemicals such as histamine and interleukins.</p> Signup and view all the answers

    Explain the difference between primary and secondary lymphoid tissues.

    <p>Primary lymphoid tissues are where lymphocytes mature, while secondary lymphoid tissues are where they exert their effector functions.</p> Signup and view all the answers

    How do cytotoxic T cells contribute to the immune response?

    <p>Cytotoxic T cells destroy target cells that are infected or malignant.</p> Signup and view all the answers

    What role do dendritic cells play as antigen-presenting cells?

    <p>Dendritic cells capture antigens and present them on their surface to activate T cells.</p> Signup and view all the answers

    What is the significance of T helper cells in relation to B cells?

    <p>T helper cells stimulate B cells to produce antibodies through signaling.</p> Signup and view all the answers

    Describe the main functions of macrophages in the immune system.

    <p>Macrophages surround and kill microorganisms while removing dead cells and stimulating other immune cells.</p> Signup and view all the answers

    Where are T cells primarily found within the lymphatic system?

    <p>T cells are mainly found in the thymus, lymph nodes, and spleen.</p> Signup and view all the answers

    Explain the role of the complement system in the immune response.

    <p>The complement system enhances the ability of antibodies and phagocytic cells to clear pathogens.</p> Signup and view all the answers

    Describe the role of NK cells in immune surveillance.

    <p>NK cells recognize and kill tumor cells and virus-infected cells, playing a critical role in immune surveillance.</p> Signup and view all the answers

    What are the primary locations of Antigen Presenting Cells (APCs) in the body?

    <p>APCs are primarily located in the skin, lymph nodes, thymus, and mucosal epithelia.</p> Signup and view all the answers

    Differentiate between granulocytes and agranulocytes based on lifespan.

    <p>Granulocytes are short-lived, surviving for 2-3 days, while agranulocytes can live for months.</p> Signup and view all the answers

    Explain the functional difference between interdigitating and follicular dendritic cells.

    <p>Interdigitating dendritic cells present antigens to T cells, while follicular dendritic cells present to B cells.</p> Signup and view all the answers

    Identify the two major types of leukocytes and give a brief function of each.

    <p>The two major types of leukocytes are granulocytes (involved in immediate immune responses) and agranulocytes (play roles in long-term immunity).</p> Signup and view all the answers

    What is the significance of the structure of white pulp in the spleen?

    <p>The white pulp in the spleen forms primary and secondary follicles, which are essential for the activation and proliferation of lymphocytes.</p> Signup and view all the answers

    How do B cells and memory cells differ in their function?

    <p>B cells are responsible for producing antibodies, while memory cells provide long-lasting immunity by recalling previous antigens.</p> Signup and view all the answers

    Discuss the role of perforin released by NK cells.

    <p>Perforin is released by NK cells to create pores in the membranes of infected or cancerous cells, leading to their lysis.</p> Signup and view all the answers

    The immune system consists of two distinct types: innate (natural) and ______ (acquired).

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

    Lymphocytes are part of the leukocyte cell lineage and include B and ______ lymphocytes.

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

    Basophils are a type of white blood cell that release substances like heparin and ______.

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

    Neutrophils are one of the first cell types to travel to the site of an ______.

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

    Immunity is defined as resistance to disease, specifically infectious ______.

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

    Eosinophils are associated with the initiation of inflammatory responses, particularly during ______ infections.

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

    The immune response is the coordinated reaction of immune ______ to infectious microbes.

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

    Neutrophils help fight infection by ingesting microorganisms and releasing ______ that kill them.

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

    Dendritic cells are a type of ______ cell that boosts immune responses.

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

    The main parts of the immune system include white blood cells, antibodies, and the ______ system.

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

    Mast cells activate inflammation by releasing ______, tumor necrosis factor, and interleukins.

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

    T Helper cells, identified by CD4+, stimulate ______ cells to produce antibodies.

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

    The ______ is classified as a primary lymphoid tissue where lymphocytes mature.

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

    Macrophages are a type of ______ cell that surrounds and kills microorganisms.

    <p>white blood</p> Signup and view all the answers

    B cells differentiate primarily in the ______ marrow.

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

    Secondary lymphoid tissues are where lymphocytes exert their ______ function.

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

    Leukocytes are divided into two main categories: granulocytes and ______.

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

    The primary function of NK cells is to recognize and kill ______ cells.

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

    Antigen Presenting Cells (APCs) present antigens to ______ cells.

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

    Eosinophils are primarily involved in combating ______ infections.

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

    Lymphocytes have a long lifespan and can live for ______.

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

    Neutrophils are known for being the first to respond to ______.

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

    Monocytes differentiate into ______ and dendritic cells.

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

    The spleen contains white pulp where ______ cells are formed.

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

    Match the immune cells with their primary functions:

    <p>Dendritic cells = Antigen presentation to T cells Macrophages = Surrounding and killing microorganisms Mast cells = Releasing histamine and initiating inflammation B cells = Producing antibodies</p> Signup and view all the answers

    Match the following immune system components with their descriptions:

    <p>Thymus = Site of T cell maturation Bone marrow = Primary lymphoid tissue for B cell origin Lymph nodes = Secondary lymphoid tissue for immune response Spleen = Filters blood and houses immune cells</p> Signup and view all the answers

    Match the types of T cells with their functions:

    <p>T Helper cells (CD4+) = Stimulate B cells Cytotoxic T cells (CD8+) = Destroy infected or cancerous cells Pre-T lymphocytes = Mature in the thymus Memory T cells = Provide long-term immunity</p> Signup and view all the answers

    Match the following immune system tissues with their categories:

    <p>Primary lymphoid tissue = Thymus and Bone marrow Secondary lymphoid tissue = Lymph nodes and spleen Mucosal-associated lymphoid tissue (MALT) = Protects mucosal surfaces Fetal liver = Site of early lymphocyte development</p> Signup and view all the answers

    Match the chemical substances released by mast cells with their effects:

    <p>Histamine = Vasodilation and increased vascular permeability Tumor necrosis factor = Promotes inflammation Interleukins = Regulate immune responses Heparin = Inhibits blood clotting</p> Signup and view all the answers

    Match the types of immune responses with their relevant categories:

    <p>Innate immune response = Immediate, non-specific defense Adaptive immune response = Specific and targeted protection Humoral immunity = B cell-mediated response Cell-mediated immunity = T cell-mediated response</p> Signup and view all the answers

    Match the immune components with their roles in the immune system:

    <p>Antibodies = Bind to antigens to mark them for destruction T cells = Directly attack infected or malignant cells Complement system = Enhances the ability of antibodies and phagocytes Lymphatic system = Transports lymph and immune cells</p> Signup and view all the answers

    Match the types of immune responses with the immune cells primarily involved:

    <p>B cell response = Antibody secretion T cell response = Cell-mediated immunity Phagocyte response = Engulfing pathogens Cytokine response = Cell signaling in immune responses</p> Signup and view all the answers

    Match the following types of leukocytes with their characteristics:

    <p>Neutrophils = Short-lived for 2-3 days Basophils = Release heparin and histamine Eosinophils = Combat parasitic infections Monocytes = Differentiate into macrophages</p> Signup and view all the answers

    Match the following immune cell types with their primary functions:

    <p>NK cells = Cytotoxic against tumor and virus-infected cells Dendritic cells = Present antigens to T cells Macrophages = Phagocytosis and antigen presentation B cells = Differentiate into plasma cells and memory cells</p> Signup and view all the answers

    Match the following secondary lymphoid organs with their functions:

    <p>Spleen = Filters blood and initiates immune responses Lymph nodes = Filters lymph and activated lymphocytes Thymus = Site for T cell maturation Mucosal tissues = Interact with antigens at body surfaces</p> Signup and view all the answers

    Match the following antigen presenting cells (APCs) with their types:

    <p>Dendritic cells = Interdigitating and follicular Macrophages = Effective phagocytes and antigen presenters Lymphocytes = Response mediators B cells = Antibody production</p> Signup and view all the answers

    Match the following leukocyte types with their lifespan:

    <p>Granulocytes = Short-lived for days Agranulocytes = Long-lived for months Eosinophils = Short-lived but crucial in allergic responses Lymphocytes = Can persist for years in memory form</p> Signup and view all the answers

    Match the following immune responses with their respective cells:

    <p>Cytotoxic response = NK cells Humoral immunity = B cells Cell-mediated immunity = T cells Innate immunity = Granulocytes</p> Signup and view all the answers

    Match the following conditions with the leukocyte type involved:

    <p>Allergic reactions = Basophils Bacterial infections = Neutrophils Viral infections = T cells Parasitic infections = Eosinophils</p> Signup and view all the answers

    Match the following types of antibodies with their features:

    <p>IgG = Most abundant in serum IgM = First antibody produced IgA = Found in mucosal areas IgE = Involved in allergic reactions</p> Signup and view all the answers

    Match the types of immune cells with their primary characteristics:

    <p>Lymphocytes = Recognize specific antigens through surface receptors Basophils = Secrete heparin and histamine during allergic reactions Eosinophils = Combat helminth infections and involved in allergic responses Neutrophils = Ingest microorganisms and are among the first responders to infection</p> Signup and view all the answers

    Match the following immune terms with their definitions:

    <p>Immunity = Resistance to infectious disease Immune response = Coordinated reaction of immune cells to infections Granulocytes = A type of white blood cell containing granules Agranulocytes = White blood cells without granules in their cytoplasm</p> Signup and view all the answers

    Match the components of the immune system with their roles:

    <p>B lymphocytes = Mature in the bone marrow and produce antibodies T lymphocytes = Mature in the thymus and regulate immune responses Macrophages = Engulf and destroy pathogens while stimulating other immune cells Dendritic cells = Present antigens to T cells and initiate immune responses</p> Signup and view all the answers

    Match the following descriptions with the correct type of immunity:

    <p>Innate immunity = Natural defense mechanisms present at birth Adaptive immunity = Responses developed after exposure to specific antigens Active immunity = Long-lasting immunity developed after infection or vaccination Passive immunity = Temporary immunity gained from maternal antibodies</p> Signup and view all the answers

    Match the following immune system disorders with their associated immune cells:

    <p>Allergic reactions = Basophils play a major role Asthma = Eosinophils are prominently involved Autoimmune diseases = T lymphocytes may mistakenly attack self-tissues Chronic infections = Neutrophils are often recruited but can become exhausted</p> Signup and view all the answers

    Match the following terms with their correct descriptions:

    <p>Phagocytosis = Process where cells engulf and destroy pathogens Cytokines = Signaling molecules that mediate and regulate immunity Antigens = Substances that induce an immune response Vaccine = Substance that stimulates the adaptive immune response without causing disease</p> Signup and view all the answers

    Match the following immune responses with their triggering factors:

    <p>Acute inflammation = Triggered by the presence of pathogens Chronic inflammation = Can result from prolonged immune response to persistent antigens Hypersensitivity reactions = Elicit overactive immune responses to non-harmful antigens Immunological tolerance = Prevents immune responses against self-antigens</p> Signup and view all the answers

    Match the following terms with their corresponding immune system components:

    <p>T Helper cells = CD4+ cells that assist other immune cells Cytotoxic T cells = Destroy infected or cancerous cells directly Memory B cells = Long-lived cells that provide immunity upon reexposure to antigens Regulatory T cells = Help maintain immune tolerance and prevent autoimmunity</p> Signup and view all the answers

    Study Notes

    Introduction to Immunology

    • The immune system protects the body from harmful invaders, including:
      • Microorganisms (bacteria, viruses, fungi, parasites)
      • Microbial toxins
      • Foreign substances (pollens, pet danders, chemicals)
    • There are two main types of immunity:
      • Innate (natural): This is the first line of defense and is always active.
      • Adaptive (acquired): This involves a specific immune response that develops after exposure to a particular pathogen.

    Key Immune System Concepts

    • Immunity: Resistance to disease, particularly infectious disease.
    • Immune System: The collection of cells, tissues, and molecules that mediate this resistance.
    • Immune Response: The coordinated reaction of these cells and molecules to infectious microbes.

    Lymphocytes: The Main Players

    • Lymphocytes are key components of the immune system. They are mononuclear cells classified as B and T cells, based on their origin:
      • B lymphocytes (B cells): Mature in the bone marrow.
      • T lymphocytes (T cells): Mature in the thymus.
    • Lymphocytes have antigen receptors on their surface, enabling them to recognize specific antigens.

    Other Important Immune Cells

    • Basophils: These are granulocytes involved in inflammatory reactions, particularly those associated with allergic symptoms. They contain granules with:
      • Heparin: Inhibits blood clotting.
      • Histamine: Causes vasodilation and increased permeability, promoting inflammation.
    • Eosinophils: These are multi-functional leukocytes involved in inflammatory responses, especially against:
      • Helminths (parasitic worms).
      • Allergies.
    • Neutrophils: These are first responders to an infection. They engulf and destroy invading microorganisms through:
      • Phagocytosis: Engulfing and digesting foreign material.
      • Enzyme release: Killing microbes.
    • Dendritic cells: These cells are located in the tissues, especially the skin. They present antigens to other immune cells, triggering an immune response. They are:
      • Phagocytes: Engulf and digest foreign matter.
      • Antigen-presenting cells (APCs): Show antigens to other immune cells.
    • Macrophages: These are large phagocytic cells that engulf and destroy microbes, remove dead cells, and activate other immune system cells.
    • Mast cells: These cells reside in connective tissue and release chemicals like histamine, tumor necrosis factor, and interleukins, triggering inflammation.

    The Role of the Immune System

    • Protection from invaders:
      • Viruses
      • Bacteria
      • Fungi
      • Parasites

    The Main Components of the Immune System

    • White blood cells: The primary cells involved in immunity.
    • Antibodies: Proteins that bind to specific antigens, neutralizing them.
    • Complement system: A series of proteins that work together to lyse cells, promote inflammation, and opsonize (tag) pathogens for phagocytosis.
    • Lymphatic system: A network of vessels and nodes that transports lymph, a fluid that carries immune cells and substances.
      • Lymph nodes: Small organs that filter lymph and are sites of immune responses.
    • Spleen: An organ that filters blood and removes old or damaged red blood cells. It also houses immune cells and plays a role in antibody production.
    • Bone marrow: The site of blood cell production, including immune cells.
    • Thymus: A gland that is essential for the development and maturation of T cells.
    • T cells: Lymphocytes that are responsible for cell-mediated immunity.
    • B cells: Lymphocytes that are responsible for humoral immunity (antibody production).

    Immune System Components: Cells and Organs

    • Lymphoid tissue: The tissues where immune cells are located and function.
      • Primary lymphoid tissue: Where lymphocytes differentiate, proliferate, and mature:
        • Bone marrow
        • Thymus
        • Fetal liver
      • Secondary lymphoid tissue: Where lymphocytes exert their effector function.
        • Spleen
        • Lymph nodes
        • Mucosal-associated lymphoid tissue (MALT)

    T Cell Function

    • Pre-T lymphocytes undergo maturation in the thymus.
    • Mature T cells migrate to secondary lymphoid tissues.
      • Spleen: Found around central arterioles in the white pulp.
      • Lymph nodes: Found in the paracortex.

    Types of T Cells

    • T Helper (TH1-2) cells: Express CD4+ molecules on their surface. They:
      • Stimulate B cells to produce antibodies.
    • Cytotoxic T (Tc) cells: Express CD8+ molecules on their surface. They:
      • Destroy target cells (infected cells, tumor cells).

    B Cell Function

    • Pre-B lymphocytes mature in the bone marrow.
    • Mature B cells migrate to secondary lymphoid tissues:
      • Spleen: Located in the white pulp and form primary and secondary follicles.
      • Lymph nodes: Found in the cortex.
    • B cells differentiate into:
      • Plasma cells: Produce antibodies.
      • Memory cells: Remember specific antigens and provide long-term immunity.

    Leukocytes: Granulocytes and Agranulocytes

    • Granulocytes: White blood cells with granules in their cytoplasm, which release signaling molecules. They are short-lived.
      • Neutrophils: The most abundant granulocytes.
      • Basophils: Involved in allergic responses.
      • Eosinophils: Involved in parasitic infections and allergic responses.
    • Agranulocytes: White blood cells that lack granules. They are long-lived.
      • Lymphocytes: The main players in adaptive immunity.
      • Monocytes: Large phagocytic cells that mature into macrophages.

    Natural Killer (NK) Cells

    • NK cells: Large granular lymphocytes that belong to the innate immune system. They are cytotoxic (cell-killing) for:
      • Tumor cells: Immune surveillance.
      • Virally infected cells: Fight viral infections.
      • Bacteria, fungi, and parasites: Innate defense.
    • Mechanisms of action:
      • Perforin: An extracellular protein that perforates cell membranes, leading to cell lysis.
      • Interferon (IFN): Proteins that inhibit viral replication.

    Antigen-Presenting Cells (APCs)

    • APCs: A heterogeneous population of leukocytes that present antigens to other immune cells.
    • Location: Found primarily in the skin, lymph nodes, thymus, and mucosal epithelia.
    • Types:
      • Macrophages: Large phagocytic cells that engulf and destroy microbes and present antigens.
      • Dendritic cells: Specialized APCs that present antigens to T cells.
        • Interdigitating dendritic cells (ID): Present antigens to T cells.
        • Follicular dendritic cells (FD): Present antigens to B cells.

    The Immune System

    • The immune system is responsible for defending the body against invading organisms and substances.
    • These invaders include living organisms like viruses, bacteria, fungi, and parasites, as well as non-living substances like toxins, pollens, pet danders, and chemicals.
    • Immunity is the body's resistance to disease, specifically infectious disease.
    • The immune system comprises cells, tissues, and molecules that work together to prevent or eradicate infections.

    Types of Immunity

    • Innate (natural) immunity: This is the body's immediate, non-specific defense system. It is always active and does not need prior exposure to an invader.
    • Adaptive (acquired) immunity: This system is specific to each pathogen it encounters and involves the development of memory cells that can quickly respond to repeat infections.

    Immune System Cells and Organs

    • Leukocytes (white blood cells): These are the primary cells of the immune system. They can be further categorized as:

      • Granulocytes: These cells contain granules in their cytoplasm. They are short-lived, lasting only 2–3 days. Examples include neutrophils, basophils, and eosinophils.
      • Agranulocytes: These cells lack granules. They live longer, for months. Examples include lymphocytes and monocytes.

    • Lymphocytes: These are crucial for adaptive immunity. Two main types exist:

      • T cells: They are derived from the thymus gland and migrate to secondary lymphoid tissues.
        • T Helper (TH1-2) Cells (CD4+): These cells stimulate B cells to produce antibodies.
        • Cytotoxic T (Tc) Cells (CD8+): These cells directly destroy target cells infected with viruses or cancer.
      • B cells: They mature in the bone marrow and migrate to secondary lymphoid tissues.
        • They differentiate into plasma cells that produce antibodies and memory cells that provide long-term immunity.

    • Natural Killer (NK) Cells: These are large granular lymphocytes that are part of innate immunity. They are cytotoxic and can kill:

      • Tumor cells
      • Virus-infected cells
      • Cells infected with bacteria, fungi, or parasites

    • Antigen-Presenting Cells (APCs): These cells present antigens to T cells, initiating adaptive immune responses. Examples include:

      • Macrophages: These cells engulf and destroy microorganisms.
      • Dendritic cells: These cells capture antigens in tissues and migrate to lymph nodes to present them to T cells.

    • Lymphoid Tissue: This tissue houses lymphocytes and facilitates immune responses.

      • Primary lymphoid tissue: This is where lymphocytes differentiate, proliferate, and mature. Examples include the bone marrow and fetal liver.
      • Secondary lymphoid tissues: This is where lymphocytes are activated and exert their effector functions. Examples include the spleen, lymph nodes, and mucosal-associated lymphoid tissue (MALT).

    Other Immune System Components

    • Antibodies: These are proteins produced by B cells. They bind to specific antigens, neutralizing them and marking them for destruction by other immune cells.
    • Complement system: This is a series of proteins that work together to augment the immune response. They can directly kill bacteria, attract immune cells, and enhance antibody binding.
    • Lymphatic system: This system is a network of vessels and nodes that transports lymph fluid, filtering it and carrying immune cells throughout the body.
    • Spleen: This organ filters blood and removes old red blood cells. It also houses lymphocytes and plays a role in antibody production.
    • Bone marrow: This is where all blood cells, including immune cells, are produced.
    • Thymus: This is where T cells mature.

    Introduction to Immunology

    • The immune system protects against foreign organisms and substances, including microbes, toxins, pollens, pet danders, and chemicals.
    • Immunity is the resistance to disease, specifically infectious disease.
    • The immune system consists of cells, tissues, and molecules that mediate resistance to infections.
    • The immune response is the coordinated reaction of these cells and molecules to infectious microbes.

    Immune System Components

    • Lymphocytes: Mononuclear cells that are part of the leukocyte cell lineage. Subdivided into B (Bone marrow-derived) and T (Thymus-derived) lymphocytes.
    • Basophils: Granulocytes that participate in inflammatory reactions, particularly those causing allergic symptoms. Their granules contain heparin and histamine.
    • Eosinophils: Polymorphic multi-functional leukocytes involved in inflammatory responses, especially helminth infections and allergic disease.
    • Neutrophils: First immune cells to arrive at the site of infection. They engulf microorganisms and release enzymes that kill them.
    • Dendritic cells: Found in tissues like the skin, they boost immune responses by presenting antigens to other immune cells.
    • Macrophages: White blood cells that engulf and kill microorganisms, remove dead cells, and stimulate other immune cells.
    • Mast cells: Granular cells found in body tissues like connective tissue. They activate inflammation by releasing substances like histamine, tumor necrosis factor, and interleukins.

    Role of The Immune System

    • Protects from viruses, parasites, fungi, and bacteria.

    Main Parts of the Immune System

    • White blood cells
    • Antibodies
    • Complement system
    • Lymphatic system (Lymph nodes)
    • Spleen
    • Bone marrow
    • Thymus
    • T cells
    • B cells

    Immune Cells and Organs

    • Lymphoid tissue:

      • Primary lymphoid tissue: Lymphocytes differentiate, proliferate, and mature (e.g., bone marrow, thymus, fetal liver).
      • Secondary lymphoid tissues: Lymphocytes exert their effector function (e.g., spleen, lymph nodes, mucosal-associated lymphoid tissue (MALT)).

    • T cells:

      • Pre-T lymphocytes mature in the thymus gland.
      • They leave the thymus and enter secondary lymphoid tissues.
      • In the spleen, they stay around central arterioles in the white pulp.
      • In lymph nodes, they are found in the paracortex.

    • Types of T cells:

      • T helper (TH1-2) Cells (CD4+): Stimulate B cells to produce antibodies.
      • Cytotoxic T (Tc) Cells (CD8+): Destroy target cells.

    • B cells:

      • Pre-B lymphocytes mature in the bone marrow.
      • They exit the bone marrow and enter secondary lymphoid tissues.
      • In the spleen, they reside in the white pulp and form primary and secondary follicles.
      • In lymph nodes, they are found in the cortex.
      • They differentiate into plasma cells and memory cells.

    • Leukocytes:

      • Granulocytes: Short-lived (2-3 days) with granules in their cytoplasm.
        • Neutrophils
        • Basophils
        • Eosinophils
      • Agranulocytes: Long-lived (months) without cytoplasmic granules.
        • Lymphocytes
        • Monocytes

    • NK cells:

      • Large granular lymphocytes.
      • Innate cytotoxic lymphocytes.
      • Function:
        • Kill tumor cells (immune surveillance).
        • Kill virally infected cells.
        • Contribute to bacterial, fungal, and parasitic infection control.
        • Release perforin, which damages cell membranes and causes lysis.
        • Produce interferons (IFNs) that protect against viral infection.

    • APC (Antigen Presenting cells):

      • Heterogeneous population of leukocytes.
      • Found primarily in the skin, lymph nodes, thymus, and mucosal epithelia.
      • Types:
        • Macrophages
        • Dendritic cells:
          • Interdigitating dendritic cells (ID): Present antigens to T cells.
          • Follicular dendritic cells (FD): Present antigens to B cells.

    The Immune System

    • The immune system defends the body against foreign organisms and substances.
    • These invaders include:
      • Living organisms (microbes)
      • Microbial toxins and byproducts
      • Foreign substances like pollen, pet dander, and chemicals
    • Immunity is defined as resistance to disease, specifically infectious disease.
    • There are two main types of immunity:
      • Innate (natural) immunity: This is the body's first line of defense, providing non-specific protection against invaders.
      • Adaptive (acquired) immunity: This is a specific response that targets specific pathogens or antigens, creating immunological memory for future encounters.
    • The most important physiological function of the immune system is to prevent or eradicate infections.

    Immune System Components

    • Lymphocytes: These mononuclear cells are part of the leukocyte lineage and are subdivided into:
      • B lymphocytes (B cells): Derived from bone marrow; express antigen receptors for recognizing specific antigens.
      • T lymphocytes (T cells): Derived from the thymus; express antigen receptors for specific antigens, playing diverse roles in immune responses.
    • Basophils: These granulocytes are involved in inflammatory reactions, especially those linked to allergic symptoms. They contain heparin and histamine within their granules.
    • Eosinophils: These multi-functional leukocytes are associated with inflammatory responses, particularly in response to helminth infections and allergic diseases.
    • Neutrophils: These are among the first immune cells to arrive at infection sites. They engulf microorganisms and release enzymes to kill them.
    • Dendritic cells: These specialized immune cells are found in tissues (like skin) and stimulate immune responses by presenting antigens to other immune cells. They act as both phagocytes and antigen-presenting cells (APCs).
    • Macrophages: These white blood cells engulf and kill microorganisms, remove dead cells, and activate other immune system cells.
    • Mast cells: These granular cells in tissues (especially connective tissue) activate inflammation by releasing substances like histamine, tumor necrosis factor, and interleukins.

    Role of the Immune System

    • The immune system protects the body from:
      • Viruses
      • Parasites
      • Fungi
      • Bacteria

    Main Parts of the Immune System

    • White blood cells (leukocytes)
    • Antibodies
    • Complement system
    • Lymphatic system (including lymph nodes)
    • Spleen
    • Bone marrow
    • Thymus
    • T cells
    • B cells

    Immune Cells and Organs

    • Lymphoid Tissue:
      • Primary Lymphoid Tissue: Where lymphocytes differentiate, proliferate, and mature. This includes fetal liver, bone marrow, and the thymus.
      • Secondary Lymphoid Tissues: Where lymphocytes exert their effector functions. This includes the spleen, lymph nodes, and mucosal-associated lymphoid tissue (MALT).

    T Cells

    • Pre-T lymphocytes mature in the thymus gland.
    • They leave the thymus to secondary lymphoid tissues (lymphatic tissues).
    • In the spleen, they reside around central arterioles in white pulp.
    • In lymph nodes, they are found in the paracortex.

    Types of T Cells

    • T Helper (TH1-2) Cells (CD4+): Stimulate B cells to produce antibodies.
    • Cytotoxic T (Tc) Cells (CD8+): Destroy target cells.

    B Cells

    • Pre-B lymphocytes mature in the bone marrow.
    • They leave the bone marrow and migrate to secondary lymphoid tissues.
    • In the spleen, they reside in white pulp and form primary and secondary follicles.
    • In lymph nodes, they are found in the cortex.
    • They differentiate into plasma cells and memory cells.

    Leukocytes: Granulocytes and Agranulocytes

    • Granulocytes: Characterized by granules in their cytoplasm; short-lived (approximately 2-3 days).
      • Neutrophils
      • Basophils
      • Eosinophils
    • Agranulocytes: Lack granules; long-lived (for months).
      • Lymphocytes
      • Monocytes

    NK Cells

    • Natural killer (NK) cells are large granular lymphocytes.
    • They are innate cytotoxic lymphocytes, meaning they can kill cells without prior sensitization.
    • They play a role in immune surveillance, recognizing and killing:
      • Tumor cells
      • Virus-infected cells
      • Bacteria, fungi, parasites
    • They release perforin, which perforates cell membranes, leading to cell lysis.
    • They also produce interferon (IF-), which protects against viral infections.

    Antigen Presenting Cells (APCs)

    • APCs are a diverse population of leukocytes that present antigens to T cells.
    • They are found in various tissues such as the skin, lymph nodes, thymus, and mucosal epithelia.
    • Types of APCs include:
      • Macrophages:
      • Dendritic cells:
        • Interdigitating dendritic cells (ID): Present antigens to T cells.
        • Follicular dendritic cells (FD): Present antigens to B cells.

    The Immune System

    • Protects the body from foreign invaders such as bacteria, viruses, fungi, parasites, toxins, and other substances like pollens, pet danders, and chemicals.
    • Two main types of immunity: innate (natural) and adaptive (acquired).
    • The most important function of the immune system is to prevent or eradicate infections.

    Immunology Terms

    • Immunity: Resistance to disease, especially infectious disease.
    • Immune system: The collection of cells, tissues, and molecules that protect the body from infection.
    • Immune response: The coordinated reaction of immune cells and molecules to infectious agents.
    • Lymphocytes: Mononuclear white blood cells that are part of the leukocyte lineage and are subdivided into B and T lymphocytes. They express antigen receptors for recognizing specific antigens.
    • Basophils: Granulocytes involved in inflammatory reactions, particularly those causing allergic symptoms. They contain granules with heparin and histamine.
    • Eosinophils: Polymorphic leukocytes involved in inflammatory responses, especially against helminths and allergies.
    • Neutrophils: Immune cells that are among the first responders to infection. They ingest microorganisms and release enzymes to kill them.
    • Dendritic cells: Immune cells found in various tissues which boost immune responses by presenting antigens to other immune cells. They are phagocytes and antigen-presenting cells (APCs).
    • Macrophages: White blood cells that engulf and kill microorganisms, remove dead cells, and stimulate other immune cells.
    • Mast cells: Granular cells located in tissues, especially connective tissue, that activate inflammation by releasing histamine, tumor necrosis factor, and interleukins.

    Parts of the Immune System

    • White blood cells: Leukocytes involved in immune responses.
    • Antibodies: Proteins produced by B lymphocytes that recognize and neutralize specific antigens.
    • Complement system: A group of proteins that work together to destroy pathogens.
    • Lymphatic system: A network of vessels and lymph nodes that transports lymph fluid and contains immune cells.
    • Spleen: An organ that filters blood and removes old red blood cells, and hosts immune cells.
    • Bone marrow: Site of blood cell production, including immune cells like B lymphocytes.
    • Thymus: Gland responsible for the maturation of T lymphocytes.
    • T cells: Lymphocytes involved in cell-mediated immunity.
    • B cells: Lymphocytes involved in humoral immunity (antibody production).

    Immune Cells and Organs

    • Lymphoid tissue: Classified into primary and secondary lymphoid tissues.
      • Primary lymphoid tissue: Where lymphocytes differentiate, proliferate, and mature (e.g., bone marrow, thymus).
      • Secondary lymphoid tissues: Where lymphocytes exert their effector functions (e.g., spleen, lymph nodes, mucosal-associated lymphoid tissue (MALT)).

    T Cells

    • Pre-T lymphocytes mature in the thymus gland.
    • Mature T cells migrate to secondary lymphoid tissues.
    • In the spleen, they reside near central arterioles in the white pulp.
    • In lymph nodes, they are found in the paracortex.

    Types of T Cells

    • T Helper (TH1-2) Cells (CD4+): Stimulate B cells to produce antibodies.
    • Cytotoxic T (Tc) Cells (CD8+): Destroy target cells.

    B Cells

    • Pre-B lymphocytes mature in the bone marrow.
    • Mature B cells migrate to secondary lymphoid tissues.
    • In the spleen, they reside in the white pulp and form primary and secondary follicles.
    • In lymph nodes, they are found in the cortex.
    • They differentiate into plasma cells (antibody producers) and memory cells.

    Leukocytes: Granulocytes & Agranulocytes

    • Granulocytes: White blood cells containing granules in their cytoplasm. They are short-lived (2-3 days). Three types:
      • Neutrophils: Phagocytize and kill microorganisms.
      • Basophils: Release histamine and heparin during inflammation.
      • Eosinophils: Involved in inflammation, particularly against parasitic infections and allergies.
    • Agranulocytes: White blood cells lacking granules in their cytoplasm. They are long-lived (months). Two types:
      • Lymphocytes: T cells and B cells involved in specific immunity.
      • Monocytes: Precursors to macrophages, which are phagocytes and APCs.

    NK Cells

    • Natural killer (NK) cells are large granular lymphocytes.
    • They are cytotoxic, killing tumor cells and viral infected cells.
    • They release perforin, which perforates cell membranes, and interferon (IFN) which combats viral infections.

    Antigen Presenting Cells (APCs)

    • Heterogeneous population of leukocytes that present antigens to other immune cells.
    • Found in the skin, lymph nodes, thymus, and mucosal epithelia.
    • Types:
      • Macrophages: Phagocytize and present antigens.
      • Dendritic cells:
        • Interdigitating dendritic cells (ID): Present antigens to T cells.
        • Follicular dendritic cells (FD): Present antigens to B cells.

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    Basic Immunology Introduction PDF

    Description

    This quiz explores the fundamental concepts of immunology, including the types of immunity and the critical role of lymphocytes in the immune response. It covers both innate and adaptive immunity as well as key immune system components. Test your knowledge of how the immune system protects the body from various harmful invaders.

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