Immunology Concepts Quiz
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Questions and Answers

What is a key characteristic of innate immunity?

  • Antigen-dependent response
  • Specific response to pathogens
  • Immediate response (correct)
  • Memory formation

    • How does adaptive immunity differ from innate immunity in terms of specificity?

  • Innate immunity is antigen-dependent.
  • Adaptive immunity is specific to antigens. (correct)
  • Both are equally specific.
  • Adaptive immunity is non-specific.

    • Which of the following statements about memory in the immune system is accurate?

  • Adaptive immunity relies on memory for future responses. (correct)
  • All immune responses involve memory.
  • Innate immunity forms memory cells.
  • Adaptive immunity lacks memory formation.

    • What is a disadvantage of innate immunity compared to adaptive immunity?

    <p>No formation of memory.</p> Signup and view all the answers

    What is the time frame for the initiation of adaptive immunity following antigen exposure?

    <p>Days to weeks</p> Signup and view all the answers

    What is the primary function of the complement system?

    <p>To enhance the immune response and aid in host defense</p> Signup and view all the answers

    Which cells are responsible for processing protein antigens into peptides for T-cell presentation?

    <p>Antigen Presenting Cells</p> Signup and view all the answers

    Which pathway is NOT a component of the complement system?

    <p>Humoral pathway</p> Signup and view all the answers

    What can block the process of apoptosis in cells?

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

    Which type of immunity is characterized by the action of antibodies?

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

    Which immune response mechanism directly involves humoral components?

    <p>B-cell differentiation into plasma cells</p> Signup and view all the answers

    What characterizes hypersensitivity reactions?

    <p>Immediate and severe immune responses</p> Signup and view all the answers

    What is the role of immunoglobulins in the immune system?

    <p>Bind to pathogens and neutralize them</p> Signup and view all the answers

    What is the primary function of maternal IgG during pregnancy?

    <p>To provide passive immunological protection to the newborn</p> Signup and view all the answers

    Which immunoglobulin is known for being the largest and typically the first to respond in a primary immune response?

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

    What role do phagocytes play in the immune system?

    <p>They engulf and digest pathogens</p> Signup and view all the answers

    Which of the following is NOT a type of phagocyte?

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

    What is the name of the compartment where engulfed pathogens are contained within phagocytes?

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

    How long does maternal IgG typically provide passive immunity to a newborn?

    <p>4-6 weeks</p> Signup and view all the answers

    Which immunoglobulin is primarily involved in allergic reactions?

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

    What is the significance of opsonins in the immune response?

    <p>They enhance the ability of phagocytes to recognize and engulf pathogens</p> Signup and view all the answers

    What is a microbe?

    <p>Microscopic organisms residing in water, soil, air.</p> Signup and view all the answers

    Which of the following are types of microbes? (Select all that apply)

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

    What is an antigen?

    <p>Any substance triggering an immune response in the body.</p> Signup and view all the answers

    What is a cytokine?

    <p>A type of protein affecting the immune system.</p> Signup and view all the answers

    What is the primary function of antibodies?

    <p>To kill or weaken infection-causing organisms.</p> Signup and view all the answers

    Which immunoglobulin is found in secretory forms in mucous membranes?

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

    IgD can activate the complement system.

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

    Which immunoglobulin is primarily associated with allergies?

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

    What is the most common antibody in blood and tissue fluid?

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

    What do phagocytes do to pathogens?

    <p>They engulf pathogens by attaching to and wrapping around them.</p> Signup and view all the answers

    What is the compartment called that contains pathogens within phagocytes?

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

    What is formed when a phagosome merges with a lysosome or granule?

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

    What percentage of total serum immunoglobulin level does IgG represent?

    <p>75%</p> Signup and view all the answers

    What is the primary role of IgG in the immune response?

    <p>Defends against diffusing toxins and spreading microbes.</p> Signup and view all the answers

    What type of immunoglobulin is usually the earliest antibody response in a primary immune response?

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

    Which of the following are types of cells in the immune system? (Select all that apply)

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

    Which of the following is NOT an immune system component?

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

    What are opsonins?

    <p>Substances present in serum that promote phagocytosis of bacteria.</p> Signup and view all the answers

    What is the definition of opsonize?

    <p>The ability of antibodies and complement components to coat harmful antigens.</p> Signup and view all the answers

    What is phagocytosis?

    <p>A process where certain living cells (phagocytes) engulf and digest other cells or particles.</p> Signup and view all the answers

    What is apoptosis?

    <p>A type of programmed cell death.</p> Signup and view all the answers

    What is an Antigen-Presenting Cell (APC)?

    <p>Cells that process protein antigens into peptides.</p> Signup and view all the answers

    Which of the following cell types are examples of Antigen-Presenting Cells (APCs)?

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

    What is the complement system?

    <p>Part of the innate immune response involved in host defense and inflammation.</p> Signup and view all the answers

    What is PMNS?

    <p>Polymorphonuclear leukocytes, a type of white blood cell.</p> Signup and view all the answers

    What is the primary function of PMNS?

    <p>They activate each other in a cascade, leading to the lysis of foreign and infected cells, engulf foreign particles and cell debris, and promote inflammation.</p> Signup and view all the answers

    Which of the following are examples of granulocytes?

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

    Granulocytes are part of the adaptive immune system.

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

    What do the lectin pathway's proteins activate each other in?

    <p>A cascade.</p> Signup and view all the answers

    The ____ pathway involves a group of protein molecules that circulate in blood and tissue.

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

    What are the main targets of PMNS?

    <p>Foreign and infected cells.</p> Signup and view all the answers

    Which of these white blood cells are classified as granulocytes?

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

    Macrophages are a type of mononuclear leukocyte.

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

    What is the main function of neutrophils?

    <p>Phagocytosis and degranulation to kill bacteria and fungi</p> Signup and view all the answers

    Basophils release ______, enzymes, and cytokines.

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

    What do eosinophils primarily target?

    <p>Parasites and various allergic reactions</p> Signup and view all the answers

    What is the myeloblast?

    <p>The precursor cell from which some granulocytes develop</p> Signup and view all the answers

    What type of immune cell are Mast Cells?

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

    What origin do Dendritic Cells come from?

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

    Mast Cells release __________ in response to antibodies.

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

    Dendritic Cells are the least potent type of antigen-presenting cells.

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

    What is the main function of Mast Cells?

    <p>Release inflammatory mediators</p> Signup and view all the answers

    What are the main targets of Dendritic Cells?

    <p>Capture and process antigens</p> Signup and view all the answers

    What type of lymphocytes mature in the thymus?

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

    What do T cells differentiate into?

    <p>Antigen-specific effector cells</p> Signup and view all the answers

    B cells are primarily involved in cell-mediated immunity.

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

    T-Helper cells are also known as ______.

    <p>CD4+</p> Signup and view all the answers

    What are the roles of plasma cells?

    <p>Antibody secretion</p> Signup and view all the answers

    Natural Killer cells are involved in attacking virus infected and tumor cells.

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

    What is the significance of memory cells in the immune response?

    <p>Involved with the secondary immune response</p> Signup and view all the answers

    Which type of immunity is specific?

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

    Innate immunity is antigen dependent.

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

    How long does adaptive immunity typically take to respond?

    <p>Days to weeks</p> Signup and view all the answers

    Innate immunity is known to be ______ specific.

    <p>non-specific</p> Signup and view all the answers

    Match the following characteristics with the type of immunity:

    <p>Immediate/hours = Innate immunity Days/weeks = Adaptive immunity No memory = Innate immunity Yes memory = Adaptive immunity</p> Signup and view all the answers

    What are the barriers of the innate immune system?

    <p>Skin, mucous membrane, temperature</p> Signup and view all the answers

    Which barrier is described as a mechanical barrier that stops the influx of pathogens?

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

    Mucous membranes compete with microbes for attachment sites.

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

    What mechanism does the mucous membrane use to deal with foreign microbes?

    <p>Competes for attachment sites, entraps microbes, and propels them out through cilia</p> Signup and view all the answers

    The body's temperature or _____ response can inhibit pathogen proliferation.

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

    Which defense mechanism uses low pH to combat pathogens?

    <p>Acidic pH</p> Signup and view all the answers

    Which chemical mediator disrupts the bacterial cell wall?

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

    What type of immune cells are involved in the phagocytic/endocytic defense mechanism?

    <p>Macrophages, dendritic cells, neutrophils</p> Signup and view all the answers

    Inflammatory response involves the recruitment of white blood cells and release of cytokines.

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

    The stomach uses _____ to create a low pH environment that kills many pathogens.

    <p>hydrochloric acid</p> Signup and view all the answers

    Match the following defense mechanisms with their examples:

    <p>Low pH = Hydrochloric acid in the stomach Chemical Mediators = Lysozyme, interferon, complement Phagocytic/Endocytic = Macrophages, dendritic cells, neutrophils Inflammatory Response = Recruitment of blood leucocytes, release of cytokines</p> Signup and view all the answers

    Which of the following are involved in the process of moving into the infection site? (Select all that apply)

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

    What role do chemokines play?

    <p>They help attract immune cells to the infection site.</p> Signup and view all the answers

    What role does histamine play in immune response?

    <p>Histamine increases blood flow and permeability to allow immune cells to reach the infection site.</p> Signup and view all the answers

    What is Oral Candidiasis?

    <p>A fungal infection caused by the overgrowth of Candida albicans.</p> Signup and view all the answers

    Which conditions are associated with Oral Candidiasis? (Select all that apply)

    <p>HIV/AIDS</p> Signup and view all the answers

    What are common clinical features of Oral Candidiasis?

    <p>White patches, redness, soreness in the mouth.</p> Signup and view all the answers

    What is Sjögren’s Syndrome?

    <p>An autoimmune disease affecting moisture-producing glands, leading to dry mouth and dry eyes.</p> Signup and view all the answers

    Sjögren's syndrome primarily affects the body's ________-producing glands.

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

    What are typical symptoms of Sjögren’s Syndrome? (Select all that apply)

    <p>Dry eyes</p> Signup and view all the answers

    What is Pemphigus Vulgaris?

    <p>A rare autoimmune disease causing painful blisters and erosions on skin and mucous membranes.</p> Signup and view all the answers

    Pemphigus Vulgaris is commonly associated with allergies.

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

    What treatments are commonly used for Oral Candidiasis?

    <p>Antifungal medications like nystatin or fluconazole.</p> Signup and view all the answers

    What are the main treatments for Pemphigus Vulgaris?

    <p>Corticosteroids and immunosuppressive drugs.</p> Signup and view all the answers

    Study Notes

    Apoptosis

    • The body uses apoptosis to get rid of unwanted or abnormal cells.
    • Apoptosis may be blocked in cancer cells.

    Antigen Presenting Cells

    • Antigen presenting cells (APCs) process protein antigens into peptides.
    • These peptides can then be presented to T cell receptors on the cell surface.
    • Some examples of APCs are macrophages, dendritic cells, and B cells.

    Complement System

    • The complement system is part of the innate immune system response.
    • The system plays a major role in host defence and inflammation.
    • The complement system consists of a group of protein molecules found circulating in the bloodstream and body tissues.
    • The proteins activate each other rapidly in a sequential cascade.
    • There are three different pathways of complement activation:
      • Classical Pathway
      • Alternative Pathway
      • Lectin Pathway
    • The complement system is a humoral system of immunity, which means it is activated by proteins found in bodily fluids.

    Innate vs Acquired Immunity

    • Innate Immunity is non-specific and immediate.
    • Acquired Immunity is specific and takes days or weeks to develop.
    • Only acquired immunity has memory.

    Innate Immune System Barriers

    • The innate immune system includes a variety of barriers:
      • Skin
      • Mucous Membranes
      • Stomach Acid
      • Normal Flora of the Gut
      • Coughing and Sneezing

    Opsonins

    • Opsonins are molecules in the body that tag pathogens for destruction by phagocytes.
    • Antibody is a type of opsonin.

    Maternal IgG

    • Maternal IgG is transferred across the placenta, providing newborn infants with passive immunity.
    • This passive immunity lasts for 4-6 months.

    IgM

    • IgM is the largest of the immunoglobulin molecules.
    • It is often the earliest antibody response during a primary immune response.
    • IgM does not last very long in the blood stream.

    Phagocytes

    • Phagocytes are cells that ingest and destroy pathogens.
    • Once a pathogen is engulfed, it is contained inside a phagosome.
    • Some examples of phagocytes are monocytes, macrophages, granulocytes, and dendritic cells.

    Microbe

    • Microscopic organisms live in various environments including water, soil, and air.
    • They can be classified into bacteria, fungi, algae, protozoa, viruses, and parasites.
    • Some microbes are harmful and cause diseases, while others are beneficial to human health.

    Antigen

    • A substance that triggers an immune response within the body.
    • Antigens have a specific molecular structure that reacts with antibodies or immune cells.
    • Examples of antigens include bacteria, viruses, fungi, parasites, and even some toxins.

    Cytokine

    • A type of protein that plays a crucial role in regulating the immune system.
    • They can either stimulate or suppress the immune response depending on the specific cytokine and its target.
    • Cytokines are naturally produced by the body, but some are produced in the laboratory for therapeutic purposes.

    Antibody (Immunoglobulin - Ig)

    • Proteins produced by activated B lymphocytes, a type of white blood cell.
    • They act as a body's defense mechanism by killing or weakening invading pathogens.
    • Antibodies circulate through the bloodstream, searching for and binding to specific antigens.
    • They are essential for the body's immune response to new pathogens or vaccines.

    Specific Immunoglobulins (Ig)

    • IgA (Immunoglobulin A)

      • Found in secretions like saliva, tears, and breast milk.
      • Serves as a protective barrier on mucous membranes of the respiratory and digestive tracts.
      • Can activate the complement system to kill some organisms.

    • IgD (Immunoglobulin D)

      • Present in blood in low concentrations.
      • Doesn't activate the complement system.
      • Found as part of the antigen receptors on B lymphocytes.

    • IgE (Immunoglobulin E)

      • Found in small amounts in serum.
      • Primarily attached to mast cells and basophils (granulocytes).
      • Elevated levels are associated with allergic reactions.

    • IgG (Immunoglobulin G)

      • The most common antibody found in blood and tissue fluids.

    Phagocytosis

    • Phagocytes engulf pathogens by attaching and wrapping around them.
    • The pathogen is then enclosed in a phagosome within the phagocyte
    • The phagosome merges with a lysosome or granule to form a phagolysosome
    • The pathogen is killed inside the phagolysosome by toxic materials, such as antimicrobial agents, enzymes, nitrogen oxides, and proteins.

    Proteins (in the immune system)

    • Proteins are large molecules composed of one or more chains of amino acids.
    • The specific order of amino acids in a protein is determined by the DNA sequence that codes for it.

    Immunoglobulins

    • Immunoglobulins (Ig) are a type of protein that functions as antibodies.
    • IgG is the most abundant immunoglobulin in serum, accounting for 75% of the total.
    • IgG defends against toxins and spreading microbes; IgG response is mainly found in the secondary immune response.
    • IgG is an effective opsonin, which means it can bind to pathogens and tag them for destruction by phagocytes.
    • Maternal IgG is transferred across the placenta to the fetus, providing passive protection for 4-6 months after birth.
    • IgM is the largest immunoglobulin molecule and is the earliest antibody response in a primary immune response.
    • IgM has a short lifespan.

    Cell Types

    • Monocytes, macrophages, granulocytes, and dendritic cells are types of phagocytes.

    Other Immune System Components

    • Antibodies are proteins that bind to specific antigens and trigger an immune response.
    • Signaling proteins, or cytokines, are proteins that help to communicate between cells in the immune system.
    • Complement proteins are proteins that help to kill pathogens by forming a membrane attack complex (MAC) or by opsonizing them.

    Opsonins

    • Substances in serum that aid in the phagocytosis of bacteria.
    • Examples include IgG antibodies and the C3b molecule from the complement system.
    • Opsonins coat antigens which allows them to be recognized by the immune system.
    • Act like tags for the immune system.

    Phagocytosis

    • A process where cells known as phagocytes engulf and digest other cells or particles.
    • An example is a neutrophil phagocytosing a bacterium.

    Apoptosis

    • A type of programmed cell death where a series of molecular steps lead to the death of a cell.
    • The body uses apoptosis to eliminate unnecessary or abnormal cells.
    • Cancer cells often block apoptosis, allowing them to grow uncontrollably.

    Antigen-Presenting Cells (APCs)

    • Process protein antigens into peptides.
    • These peptides are presented to T-cell receptors.
    • Examples include macrophages, dendritic cells, and B cells.

    Complement System

    • Part of the innate immune response involved in host defense and inflammation.
    • Plays a vital role in the immune response.
    • Activated through three pathways: classical, alternative, and lectin pathways.

    Polymorphonuclear Leukocytes (PMNs)

    • PMNs are a type of white blood cell (WBC).
    • They are part of the innate immune system and are crucial for the body's defense against infection.
    • PMNs are responsible for engulfing foreign particles and cell debris, a process known as phagocytosis.
    • They also promote inflammation, a vital response to injury and infection.

    Lectin Pathway

    • The lectin pathway is a component of the innate immune system.
    • It involves a cascade of protein molecules that circulate in blood and tissues.
    • Activation of the lectin pathway leads to the destruction of foreign and infected cells (lysis), phagocytosis of foreign particles, and inflammation of surrounding tissues.

    Granulocytes

    • Granulocytes are a type of white blood cell (WBC).
    • They are characterized by the presence of granules in their cytoplasm.
    • Examples of granulocytes include neutrophils, eosinophils, basophils, and mast cells.
    • They play a crucial role in the innate immune system's response to infectious organisms.

    White Blood Cell Types

    • Macrophages are mononuclear leukocytes originating from myeloblasts and are part of the innate immune system. They engulf and destroy old, damaged, and dead cells, present antigens to T cells, and attract other phagocytic cells.
    • Neutrophils belong to the granulocyte category, originating from myeloblasts. They are part of the innate immune system and fight bacteria and fungi through phagocytosis and degranulation.
    • Eosinophils also belong to the granulocyte category and originate from myeloblasts. They are part of the innate immune system and fight parasites and contribute to various allergic reactions through degranulation.
    • Basophils, like eosinophils, are granulocytes originating from myeloblasts. These innate immune cells contribute to various allergic reactions and secrete anticoagulants like heparin which promotes WBC mobility.

    Monocytes

    • Monocytes can differentiate into macrophages.
    • Kupffer cells, specialized macrophages, are found in the liver.

    Granulocytes

    • Neutrophils, eosinophils, and basophils are granulocytes, named for the granules that are visible in their cytoplasm.
    • Myeloblasts are precursor cells that some granulocytes develop from.

    Mast Cells

    • Mast cells are granulocytes that originate from bone marrow myeloid stem cells.
    • They are innate immune cells.
    • Mast cells release inflammatory mediators, which attract immune cells to sites of injury, upon activation by allergens, pathogens, or other stimuli.
    • Mast cells play a crucial role in hypersensitivity reactions, releasing histamine to dilate blood vessels and increase immune cell recruitment.
    • They are involved in host defense against parasitic infections and allergic reactions.

    Dendritic Cells

    • Dendritic cells are mononuclear leukocytes derived from monocytes.
    • They are found in lymph nodes and the spleen.
    • Dendritic cells are innate immune cells.
    • They are crucial for linking innate and adaptive immunity, acting as messengers between the two systems.
    • Dendritic cells are potent antigen-presenting cells, key regulators of the immune system.
    • They activate immature T cells and stimulate B cell growth and differentiation to initiate the adaptive immune response.
    • Their primary role is to capture and process antigens.

    Lymphocyte Cells

    • Lymphocytes are mononuclear leukocytes and blood cells
    • T and B cells mature in the thymus and bone marrow respectively
    • T cells differentiate into antigen-specific effector cells
    • B cells differentiate into plasma cells (antibody-secreting) and memory (effector) cells
    • T cells are involved in both innate and adaptive immune responses
    • T cells are essential for helping B cells respond to antigen
    • T cells mediate cell-mediated immunity
    • T cells include T-Helper cells (Th) (CD4+), and Cytotoxic T cells (CD8+)
    • B cells are involved in the humoral/antibody mediated response
    • Th cells are involved in responses to intracellular bacteria
    • Cytotoxic T cells target virus-infected and tumor cells
    • Natural Killer cells target virus-infected and tumor cells
    • Natural Killer cells belong to the innate immune system
    • Foreign antigens trigger adaptive immune responses
    • Antibodies are produced by B cells
    • Memory cells facilitate secondary immune responses

    Innate Immunity

    • Immediate defense mechanism
    • Non-specific, meaning it recognizes and attacks broad categories of pathogens, not specific individual antigens (e.g., bacteria, viruses)
    • Present from birth
    • Does not require prior exposure to a pathogen
    • Does not develop memory of encounters
    • Consists of physical barriers like skin, mucous membranes, cilia, and chemical barriers like lysozymes, saliva, gastric acid, and antimicrobial peptides.
    • Also includes cells: Neutrophils, macrophages, NK cells, and complement system.

    Adaptive Immunity

    • Adaptive immune system develops through exposure to a pathogen
    • Specific meaning, it targets specific antigens on pathogens
    • Requires antigen-dependent activation
    • Creates memory of the encounter leading to faster responses upon subsequent exposure to the same pathogen
    • Consists of B-cells leading to production of antibodies and T-cells that destroy cells hosting pathogens
    • Consists of humoral immunity ( antibodies) and cell-mediated immunity (T-cells)

    Innate Immune Barriers

    • Skin: The first line of defense against pathogens. It's a physical barrier, making it difficult for pathogens to enter the body.
    • Mucous Membranes: Found in areas exposed to the environment like the nose, respiratory tract, and oral cavity. Mucous membranes are comprised of mucus, which helps trap pathogens, and cilia, which sweep pathogens out of the body. Normal flora also compete with pathogens for attachment sites in the mucous membranes.
    • Temperature: The body's temperature can inhibit pathogen growth. Fever is a response to infection and can help fight off pathogens.

    Oral Cavity Barriers

    • Skin
      • The skin is the most outer protective layer of the body
      • It acts as a mechanical barrier
    • Mucous membrane
      • The oral cavity is lined by a mucous membrane
      • The mucous membrane produces mucus which traps pathogens
      • The oral cavity also contains normal flora, such as bacteria, which compete with pathogens for attachment sites.

    Low pH

    • The stomach's acidic environment, due to hydrochloric acid, eliminates a significant portion of ingested pathogens

    Chemical Mediators

    • Lysozyme is a vital enzyme found in bodily fluids like tears and saliva, effectively disrupting bacterial cell walls and inhibiting their growth.
    • Interferon is a critical protein that activates antiviral defenses within cells, hindering viral replication and infection.
    • Complement is a crucial protein system that directly lyses (destroys) pathogens or facilitates their uptake by phagocytic cells, enhancing immune response effectiveness.
    • Lysozyme and histamine are both antimicrobial peptides capable of directly combatting pathogens.

    Phagocytic/Endocytic

    • Macrophages are highly specialized cells that engulf and eliminate pathogens, acting as frontline defenders against infection.
    • Dendritic cells play a vital role in processing antigens (foreign particles) and presenting them to other immune cells, initiating an adaptive immune response.
    • Neutrophils are abundant white blood cells that rapidly migrate to sites of infection, engulfing and destroying pathogens.

    Inflammatory Response

    • Damaged or infected tissues trigger the recruitment of white blood cells (leukocytes).
    • Cytokines , signaling molecules, are released from damaged tissues and immune cells, initiating the inflammatory response and attracting phagocytic cells to the affected area.

    Innate Immunity

    • Key characteristic: Non-specific defense against pathogens.
    • Specificity: Recognizes broad patterns on pathogens, not specific antigens.
    • Disadvantage: Limited ability to adapt to new pathogens.
    • Time frame: Immediate response upon infection.

    Adaptive Immunity

    • Specificity: Recognizes specific antigens on pathogens.
    • Memory: Can remember previously encountered pathogens and mount a stronger, faster response upon re-exposure.
    • Time frame: Delayed response (days to weeks) following initial exposure to an antigen.

    Immune System Components

    • Complement system: A group of proteins that work together to kill pathogens.
    • Antigen-presenting cells (APCs): Cells that display antigens to T cells.
    • Phagocytes: Cells that engulf and destroy pathogens.
    • Immunoglobulins (antibodies): Proteins produced by B cells that bind to antigens.

    Phagocytes

    • Types: Neutrophils, macrophages, dendritic cells.
    • Role: Engulf and digest pathogens.
    • Compartment: Phagosome - a compartment within phagocytes where pathogens are contained.

    Immunoglobulins (Antibodies)

    • IgM: Largest immunoglobulin, often the first to be produced in a primary immune response.
    • IgG: Most abundant immunoglobulin in blood and tissue fluid, crosses the placenta to provide passive immunity to a newborn.
    • IgE: Primarily involved in allergic reactions.
    • IgA: Found in secretory forms in mucous membranes.

    Other Immune Cells

    • T cells: Mature in the thymus and differentiate into different types with specific functions.
    • B cells: Produce antibodies.
    • Natural killer (NK) cells: Target virus-infected cells and tumor cells.

    Innate Immune Barriers

    • Mechanical barriers: Skin, mucous membranes.
    • Chemical barriers: Stomach acid, lysozyme, defensins.
    • Cellular barriers: Phagocytes, NK cells, complement system.

    Immune Response Mechanisms

    • Phagocytosis: Engulfing and digesting pathogens.
    • Inflammation: Recruitment of immune cells and release of cytokines.
    • Apoptosis: Programmed cell death, a mechanism to eliminate infected cells.
    • Opsonization: Process of coating pathogens with opsonins (e.g., antibodies, complement proteins) to enhance phagocytosis.

    Immune System Terminology

    • Antigen: Any substance that can bind to an antibody or T cell receptor and trigger an immune response.
    • Cytokine: A signaling molecule that helps coordinate immune responses.
    • Microbe: A microscopic organism, such as bacteria, viruses, fungi, or protozoa.

    Immune System Cells

    • Granulocytes: White blood cells with granules in their cytoplasm (e.g., neutrophils, eosinophils, basophils).
    • Mononuclear leukocytes: White blood cells with a single nucleus (e.g., macrophages, lymphocytes).

    Immune System Pathways

    • Complement pathway: A cascade of protein reactions that leads to the destruction of pathogens.
    • Lectin pathway: One of the pathways that activates the complement system.

    Immune Cell Functions

    • Neutrophils: Key phagocytic cells, often the first responders to infection.
    • Basophils: Release histamine and other inflammatory mediators.
    • Eosinophils: Target parasites.
    • Mast cells: Release histamine and other inflammatory mediators in response to allergens or pathogens.
    • Dendritic cells: Potent antigen-presenting cells, crucial for initiating adaptive immune responses.

    Immune System Memory

    • Memory cells: Long-lived cells that provide rapid and specific immune responses upon re-exposure to a pathogen.

    Immune System Response

    • Specificity: The ability to discriminate between self and non-self antigens.
    • Antigen dependence: The requirement for exposure to a specific antigen to trigger an immune response.
    • Time frame: Innate immunity responds immediately, while adaptive immunity takes days to weeks to develop.

    Matching Immune System Characteristics with Type of Immunity

    • Specificity: Adaptive immunity
    • Memory: Adaptive immunity
    • Fast response: Innate immunity
    • Non-specific: Innate immunity
    • Antigen dependent: Adaptive immunity

    Immune System Defense Mechanisms

    • Mechanical barriers: Skin, mucous membranes, cilia.
    • Chemical barriers: Stomach acid, lysozyme, defensins, mucus.
    • Cellular barriers: Phagocytes, NK cells, complement system.
    • Inflammatory response: Recruitment of immune cells and release of cytokines.

    Immune Cell Recruitment

    • Chemokines: Chemical signals attract immune cells to the site of infection.
    • Histamine: A chemical mediator that dilates blood vessels and increases vascular permeability, allowing immune cells to enter the infected tissue.

    Oral Candidiasis

    • A fungal infection caused by Candida albicans, commonly known as thrush when it affects the mouth.
    • Candida albicans is a normal component of the oral flora but overgrows when the immune system is compromised.
    • In immunocompromised patients, the immune system is less effective at controlling the growth of Candida, leading to overgrowth.
    • Characterized by white, creamy patches on the tongue, inner cheeks, roof of the mouth, and throat.
    • Can cause redness and soreness in the mouth, which can lead to difficulty swallowing or eating.
    • In severe cases, it can spread to other parts of the body, causing systemic infection (esophageal candidiasis).
    • Common in people with HIV/AIDS, cancer patients undergoing chemotherapy, or individuals taking immunosuppressive medications.
    • Can also be associated with systemic diseases that weaken the immune system, such as diabetes.

    Sjögren’s Syndrome

    • An autoimmune disease that primarily affects the body's moisture-producing glands, leading to dry mouth (xerostomia) and dry eyes.
    • Causes the immune system to attack the salivary glands, reducing saliva production and leading to dry mouth.
    • Saliva is a key protective factor in the oral cavity, helping to wash away food particles, neutralize acids, and prevent bacterial overgrowth.
    • Without adequate saliva, the risk of oral infections increases.
    • Presents with dry mouth (xerostomia), which can make speaking, swallowing, and tasting difficult.
    • Increased susceptibility to dental caries, oral infections, and oral candidiasis.
    • Swelling of the salivary glands, particularly the parotid glands (located near the jawline).
    • Can occur on its own (primary Sjögren’s) or in conjunction with other autoimmune diseases, such as rheumatoid arthritis or lupus.

    Pemphigus Vulgaris

    • A rare, chronic autoimmune disease that causes painful blisters and erosions on the skin and mucous membranes, including the oral cavity.
    • Occurs when the immune system produces antibodies that mistakenly attack the proteins that hold epithelial cells together (desmosomes).
    • This leads to the breakdown of cell-to-cell adhesion in the epithelium, causing blisters and erosions in the mouth and other mucous membranes.
    • Presents with painful blisters and ulcers in the mouth, especially on the gums, cheeks, and tongue.
    • Oral lesions are often one of the first signs of the disease and can make eating, drinking, and speaking very painful.
    • The blisters are fragile and often rupture, leaving raw, exposed areas that are prone to infection.
    • An autoimmune disease that is often chronic and requires long-term management.
    • Associated with an increased risk of oral infections due to the damage to the mucosal barrier.

    Management and Treatment

    • Oral Candidiasis:

      • Antifungal medications, such as nystatin or fluconazole, are used to control fungal overgrowth.
      • Maintaining good oral hygiene and using antifungal mouth rinses can help prevent recurrences.

    • Sjögren’s Syndrome:

      • Treatment focuses on managing symptoms, such as using artificial saliva, drinking plenty of fluids, and practicing good oral hygiene to prevent cavities.
      • Immunosuppressive drugs may be prescribed to control the autoimmune process.

    • Pemphigus Vulgaris:

      • Corticosteroids and immunosuppressive drugs are the main treatments to reduce the immune system’s attack on the epithelial cells.
      • Oral lesions may require topical steroids or other medications to promote healing and reduce pain.

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    Description

    Test your knowledge on key immunology concepts including apoptosis, antigen presenting cells, and the complement system. This quiz covers the mechanisms through which the body manages unwanted cells and activates immune responses.

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