1050 Unit 1 - Intro, Innate, Adaptive, and Ag+MHC
160 Questions
2 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 focus of immunology?

  • The study of vaccines and their development
  • The analysis of genetic factors influencing immunity
  • The examination of environmental impacts on immune responses
  • The study of a host's reactions to foreign substances (correct)

    • Which of the following best describes an antigen?

  • A structural protein found in cells of the immune system
  • A pathogen that causes disease in humans
  • A cell type responsible for the adaptation of immunity
  • A foreign substance that induces a host response (correct)

    • Which type of immunity is characterized by a rapid and generalized response to pathogens?

  • Specific immunity
  • Innate immunity (correct)
  • Adaptive immunity
  • Acquired immunity

    • What is the meaning of 'attenuation' in the context of immunology?

    <p>Making a pathogen less virulent through various methods</p> Signup and view all the answers

    Which of the following is NOT a component of the innate immune system?

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

    What best distinguishes adaptive immunity from innate immunity?

    <p>Adaptive immunity involves memory cells for faster responses upon re-exposure</p> Signup and view all the answers

    Which organ is primarily associated with the development of T lymphocytes?

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

    What is the main function of dendritic cells?

    <p>To phagocytize antigens and present them to helper T-lymphocytes</p> Signup and view all the answers

    Which type of cell is primarily responsible for antibody production?

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

    Which of the following statements about T cells is incorrect?

    <p>All T cells mature in the bone marrow.</p> Signup and view all the answers

    What percentage of circulating white blood cells do lymphocytes typically represent?

    <p>20% to 40%</p> Signup and view all the answers

    Which cell type functions as the most potent phagocytic cell?

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

    What role do helper T cells play in the immune response?

    <p>Stimulate B cells and assist other T cells.</p> Signup and view all the answers

    What occurs after B cells make contact with an antigen?

    <p>They differentiate into plasma cells.</p> Signup and view all the answers

    What is the primary function of neutrophils?

    <p>Phagocytosis and destruction of foreign particles</p> Signup and view all the answers

    Which of the following is a characteristic of natural killer (NK) cells?

    <p>They have a large round nucleus.</p> Signup and view all the answers

    What percentage of white blood cells do eosinophils typically comprise?

    <p>1% to 4%</p> Signup and view all the answers

    Which type of white blood cell is primarily involved in allergic reactions?

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

    How long do neutrophils typically survive after entering tissue?

    <p>5 days</p> Signup and view all the answers

    What characterizes the nucleus of eosinophils?

    <p>Bi-lobed or ellipsoidal</p> Signup and view all the answers

    What are macrophages involved in aside from phagocytosis?

    <p>Processing and presenting antigens to T cells</p> Signup and view all the answers

    What is a major role of mast cells?

    <p>Inducing and maintaining allergic reactions</p> Signup and view all the answers

    From which cells do macrophages originate?

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

    What type of granules do monocytes contain?

    <p>Peroxidase and lysozyme</p> Signup and view all the answers

    Which type of white blood cell typically comprises less than 1% of circulating WBCs?

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

    What is a defining characteristic of natural killer (NK) cells?

    <p>They have kidney-shaped nuclei and granular cytoplasm.</p> Signup and view all the answers

    Which primary lymphoid organ is responsible for the maturation of T lymphocytes?

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

    What role do innate lymphoid cells (ILCs) primarily serve?

    <p>They play a role in innate immunity and tissue remodeling.</p> Signup and view all the answers

    What is the main function of the red pulp in the spleen?

    <p>To destroy old red blood cells.</p> Signup and view all the answers

    Which secondary lymphoid organ is NOT correctly matched with its function?

    <p>MALT - Store of red blood cells.</p> Signup and view all the answers

    What is a primary function of B lymphocytes in the secondary lymphoid organs?

    <p>To produce antibodies following antigen exposure.</p> Signup and view all the answers

    What component of the spleen contains T cells arranged around arterioles?

    <p>White pulp</p> Signup and view all the answers

    Which of the following is NOT a secondary lymphoid organ?

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

    What is the primary function of B cells in the adaptive immune response?

    <p>To differentiate into plasma cells to secrete antibodies</p> Signup and view all the answers

    Which of the following correctly identifies a subtype of T lymphocytes?

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

    Natural killer (NK) cells have the capability to:

    <p>Kill virally infected or cancerous cells without prior exposure</p> Signup and view all the answers

    Which organs are classified as primary lymphoid organs where lymphocyte maturation occurs?

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

    Contact of lymphocytes with foreign antigens occurs primarily in which type of organ?

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

    What is the primary function of lymph nodes?

    <p>To filter lymph fluid and collect lymphocytes</p> Signup and view all the answers

    Where do B lymphocytes undergo transformation into plasma cells?

    <p>In secondary follicles of the cortex</p> Signup and view all the answers

    Which cells are predominantly found in the paracortex of lymph nodes?

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

    What characterizes adaptive immunity?

    <p>Specificity and dependence on lymphocytes</p> Signup and view all the answers

    Which of the following structures is NOT considered part of MALT?

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

    Which statement about innate immunity is true?

    <p>It includes normally present, nonspecific body functions.</p> Signup and view all the answers

    Which type of cells are actively phagocytic and involved in innate immunity?

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

    What type of cells are primarily found in CALT?

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

    What role do mucous membranes play in the external defense system?

    <p>They serve as a physical barrier to pathogen entry.</p> Signup and view all the answers

    Which component of the digestive system helps to maintain a low pH that inhibits microorganism growth?

    <p>Hydrochloric acid in the stomach</p> Signup and view all the answers

    What is the function of lysozyme found in tears and saliva?

    <p>To attack the cell walls of gram-positive bacteria.</p> Signup and view all the answers

    How do cilia in the respiratory tract contribute to pathogen defense?

    <p>They propel mucus containing pathogens out of the lungs.</p> Signup and view all the answers

    What role does urine play in the genitourinary tract's defense against pathogens?

    <p>It flushes out pathogens from the body.</p> Signup and view all the answers

    What is the primary role of the external defense system in the innate immune system?

    <p>To prevent infectious agents from entering the body</p> Signup and view all the answers

    Which component of the skin plays a key role in forming a physical barrier to pathogens?

    <p>Keratin in epithelial cells</p> Signup and view all the answers

    Which of the following statements best describes the role of lactic and fatty acids on the skin?

    <p>They discourage microorganism growth by maintaining a low pH.</p> Signup and view all the answers

    What type of response does the adaptive immune system elicit when a pathogen interacts directly with a B cell?

    <p>Humoral response dependent on IgM antibodies</p> Signup and view all the answers

    Which of the following best describes 'pattern-recognition receptors' within the innate immune system?

    <p>Sensors that identify common features of pathogens</p> Signup and view all the answers

    During inflammation, what is the primary purpose of the acute-phase reactants?

    <p>To enhance the inflammatory response and pathogen elimination</p> Signup and view all the answers

    What primarily characterizes the anatomical barriers of the external defense system?

    <p>Consist of physical, chemical, and biological barriers</p> Signup and view all the answers

    Which of the following best captures the nature of the innate immune system's response to pathogens?

    <p>It employs a variety of nonspecific mechanisms immediately upon detection.</p> Signup and view all the answers

    What is the main function of pattern-recognition receptors (PRRs)?

    <p>To recognize molecules unique to infectious organisms.</p> Signup and view all the answers

    How do Toll-like receptors (TLRs) contribute to immune response?

    <p>By binding to microbial substances and activating cytokine production.</p> Signup and view all the answers

    What is a primary role of acute-phase reactants during an infection?

    <p>To facilitate contact between microbes and phagocytic cells.</p> Signup and view all the answers

    Which of the following correctly describes the function of C-reactive protein?

    <p>Enhances opsonization and activates complement pathways.</p> Signup and view all the answers

    Which of the following cytokines is primarily produced by retinoic acid-inducible gene-I-like receptors (RLRs)?

    <p>Interferons.</p> Signup and view all the answers

    What role do inflammation and its cardinal signs serve in the body?

    <p>To initiate a defense against injury or infection.</p> Signup and view all the answers

    Which acute-phase reactant increases 1000X in response to inflammation and aids in opsonization and complement activation?

    <p>C-reactive protein.</p> Signup and view all the answers

    What characterizes the majority of TLRs in humans?

    <p>They are a type of glycoprotein that binds microbial substances.</p> Signup and view all the answers

    What is the primary physiological response during inflammation characterized by redness, heat, swelling, and pain?

    <p>Increased blood flow and immune response.</p> Signup and view all the answers

    What is the typical response time for serum amyloid A as an acute-phase reactant?

    <p>24 hours.</p> Signup and view all the answers

    Which of the following best describes acute-phase reactants?

    <p>Serum proteins that increase in response to infection or injury.</p> Signup and view all the answers

    How does inflammation assist the immune response following injury or infection?

    <p>By facilitating the migration of neutrophils and macrophages to the affected area.</p> Signup and view all the answers

    Which mechanism is NOT involved in the killing of microbes following phagocytosis?

    <p>Release of neuropeptides.</p> Signup and view all the answers

    Which type of cells are the first line of defense against virally infected cells, cells infected with other intracellular pathogens, and tumor cells?

    <p>Natural Killer (NK) cells</p> Signup and view all the answers

    What key process enhances the ability of phagocytic cells to identify and eliminate pathogens?

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

    Which of the following statements about innate immunity is accurate?

    <p>It does not rely on prior exposure and has the same response each time.</p> Signup and view all the answers

    Which of the following cells does NOT typically induce an oxidative burst during phagocytosis?

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

    What primary function do innate lymphoid cells (ILCs) serve in the immune system?

    <p>Release of immunoregulatory cytokines</p> Signup and view all the answers

    What is the main outcome of the oxidative burst during phagocytosis?

    <p>Generation of reactive oxygen species</p> Signup and view all the answers

    What characterizes the response of phagocytic cells to pathogens during the inflammatory response?

    <p>They are the first to detect and respond to antigens.</p> Signup and view all the answers

    Which of the following best describes the role of cytokines produced by Natural Killer (NK) cells?

    <p>They recruit other immune cells, such as T cells.</p> Signup and view all the answers

    What is the primary role of Major Histocompatibility Complex (MHC) molecules?

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

    What determines whether transplanted tissue is accepted or rejected?

    <p>Major Histocompatibility Complex molecules</p> Signup and view all the answers

    What is a characteristic of heteroantigens?

    <p>They come from microorganisms that share structural similarity with the host's antigens</p> Signup and view all the answers

    Which statement best describes the function of MHC molecules in the immune response?

    <p>They carry peptide antigens for T cell recognition</p> Signup and view all the answers

    What is a consequence of the cross-reactivity observed with heterophile antigens?

    <p>Potential for misidentification of self as non-self</p> Signup and view all the answers

    Which class of MHC molecules is found on all nucleated cells?

    <p>Class I MHC Molecules</p> Signup and view all the answers

    What is the size range of peptides bound by Class II MHC molecules?

    <p>13 to 18 amino acids</p> Signup and view all the answers

    Which T cell type interacts with Class I MHC molecules?

    <p>CD8+ T cells</p> Signup and view all the answers

    Which of the following statements about the structure of Class I and II MHC molecules is correct?

    <p>Class I has one α chain and one β2-microglobulin.</p> Signup and view all the answers

    What is a key clinical significance of MHC classes I and II?

    <p>They can both induce graft rejection.</p> Signup and view all the answers

    What is true about immunogens in relation to antigens?

    <p>Immunogens are specific types of antigens that always trigger an immune response.</p> Signup and view all the answers

    Which characteristic is most important for a substance to function effectively as an immunogen?

    <p>Ability to be processed and presented by MHC molecules</p> Signup and view all the answers

    Why are proteins considered more effective immunogens compared to carbohydrates?

    <p>Proteins have more complex structures that can evoke a stronger response.</p> Signup and view all the answers

    How does 'foreignness' impact the efficacy of an immunogen?

    <p>Immunogens that are more unrelated to the host trigger stronger immune responses.</p> Signup and view all the answers

    What minimum macromolecular size is generally recognized to trigger an immune response?

    <p>10,000 daltons</p> Signup and view all the answers

    Which statement about the characteristics of immunogens is false?

    <p>All immunogens can be processed by MHC molecules.</p> Signup and view all the answers

    What factor does NOT influence the immunogenicity of a substance?

    <p>Physical state of the substance</p> Signup and view all the answers

    What must occur before small peptides can combine with MHC molecules?

    <p>They must undergo enzymatic digestion.</p> Signup and view all the answers

    Which type of epitope consists of amino acids that are sequential on a single polypeptide chain?

    <p>Linear epitopes</p> Signup and view all the answers

    Which of the following best characterizes T cell activation?

    <p>Depends on the combination of peptides with MHC proteins.</p> Signup and view all the answers

    What is the role of haptens in immunology?

    <p>They are nonimmunogenic unless combined with a carrier.</p> Signup and view all the answers

    Which class of MHC molecules is expressed on all nucleated cells?

    <p>Class I</p> Signup and view all the answers

    How are conformational epitopes on an immunogen formed?

    <p>The folding of one or more polypeptide chains.</p> Signup and view all the answers

    Which protein structure level is characterized by the unique sequence of amino acids?

    <p>Primary protein structure</p> Signup and view all the answers

    What is the primary role of Class I MHC molecules in the immune system?

    <p>Process endogenous antigens for CD8+ T cells</p> Signup and view all the answers

    How do B cells typically get activated?

    <p>By recognizing and cross-linking surface immunoglobulins.</p> Signup and view all the answers

    What is unique about the HLA system in humans?

    <p>It is the most polymorphic gene system</p> Signup and view all the answers

    Epitopes recognized by B cells differ from those recognized by T cells in which way?

    <p>B cells respond to free antigens, while T cells need MHC association.</p> Signup and view all the answers

    Which of the following is NOT a characteristic of Class III MHC molecules?

    <p>Is expressed on cell surfaces</p> Signup and view all the answers

    Where on the chromosome are the genes coding for MHC molecules found?

    <p>Short arm of Chromosome 6</p> Signup and view all the answers

    Which type of antigens do Class I MHC molecules primarily process?

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

    Which class of MHC molecules includes the gene loci designated as DR, DQ, and DP?

    <p>Class II</p> Signup and view all the answers

    Which component is NOT a part of Class I MHC molecules?

    <p>Complement components</p> Signup and view all the answers

    Which allele(s) are associated with celiac disease and type I diabetes?

    <p>DQ2 and DQ8</p> Signup and view all the answers

    Which HLA allele is associated with type 1 diabetes?

    <p>DQ8</p> Signup and view all the answers

    Which of the following diseases is associated with HLA allele B27?

    <p>Ankylosing spondylitis</p> Signup and view all the answers

    Which term describes small, nonimmunogenic substances that require a large carrier to provoke an immune response?

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

    What role do adjuvants play in the immune response?

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

    Which HLA allele shows a clear association with rheumatoid arthritis?

    <p>DR4</p> Signup and view all the answers

    Which of the following accurately describes heteroantigens?

    <p>Originating from unrelated species</p> Signup and view all the answers

    What is the primary function of Major Histocompatibility Complex (MHC) molecules?

    <p>Presentation of antigens to T cells</p> Signup and view all the answers

    What are the two primary types of cells formed during the antigen-dependent phase of B-cell activation?

    <p>Memory cells and antibody-secreting plasma cells</p> Signup and view all the answers

    Which protein is commonly found on the surface of activated B cells that distinguishes them as plasma cells?

    <p>CD138</p> Signup and view all the answers

    What is the primary location where activated B cells are found?

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

    During the adaptive immune response, what drives the differentiation of T cells into specific subsets?

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

    In what part of the body do T cells primarily circulate to find antigen-presenting cells (APCs)?

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

    What is the primary function of the pre-B cell receptor (pre-BCR) in pre-B cells?

    <p>To facilitate the expression of surface immunoglobulins</p> Signup and view all the answers

    Which of the following statements best describes the fate of immature B cells that react with self-antigens?

    <p>They undergo apoptosis in the bone marrow</p> Signup and view all the answers

    What distinguishes follicular B cells from marginal B cells?

    <p>Follicular B cells primarily circulate in lymph nodes</p> Signup and view all the answers

    What role do surface immunoglobulins IgM and IgD play on mature B cells?

    <p>They provide activating signals upon contact with antigens</p> Signup and view all the answers

    Which of the following surface proteins is not typically associated with B cells?

    <p>Cytotoxic T-cell markers</p> Signup and view all the answers

    What is a characteristic feature of adaptive immunity?

    <p>Memory of prior exposure to antigen</p> Signup and view all the answers

    During which stage of T-cell differentiation do thymocytes express both CD4 and CD8?

    <p>Double-Positive (DP) Stage</p> Signup and view all the answers

    What occurs during the positive selection process of T-cell differentiation?

    <p>Thymocytes survive if their TCR recognizes MHC moderately</p> Signup and view all the answers

    What are the main functions of CD4 T cells?

    <p>Secreting cytokines and influencing antibody production</p> Signup and view all the answers

    What drives the migration of T-cell precursors to the cortex of the thymus?

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

    Which MHC protein do cytotoxic T cells recognize?

    <p>Class I MHC protein</p> Signup and view all the answers

    What is the role of negative selection in T-cell development?

    <p>To induce apoptosis in thymocytes binding to self-antigens</p> Signup and view all the answers

    What is the first step in B-cell differentiation?

    <p>Rearrangement of genes coding for antibodies</p> Signup and view all the answers

    Which type of immunity primarily utilizes B lymphocytes and antibodies?

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

    Which type of cells account for approximately two-thirds of peripheral T cells?

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

    What occurs after a B cell is activated by an antigen?

    <p>Transformation into antibody-producing plasma cells</p> Signup and view all the answers

    What is a defining feature of the adaptive immune response compared to innate defenses?

    <p>It is slow to activate but provides lasting immunity</p> Signup and view all the answers

    What is true about pro-B cells in B-cell differentiation?

    <p>They undergo gene rearrangement for antibody specificity.</p> Signup and view all the answers

    Which of the following statements best describes the composition of the TCR?

    <p>It includes both alpha and beta chains</p> Signup and view all the answers

    Which of the following statements about T-cell differentiation is correct?

    <p>Both CD4 and CD8 T cells participate in immune response regulation.</p> Signup and view all the answers

    What is the significance of the B cell differentiation process?

    <p>Differentiation allows B cells to produce diverse antibodies.</p> Signup and view all the answers

    Which correctly identifies the function of T Regulatory (Treg) cells?

    <p>Suppress immune responses to self-antigens</p> Signup and view all the answers

    What is a characteristic of T cell-dependent antigens?

    <p>They require interaction with CD4+ T cells.</p> Signup and view all the answers

    What is a key difference between T cell-independent and T cell-dependent antigens?

    <p>B cells are activated independently of helper T cells by T cell-independent antigens.</p> Signup and view all the answers

    Which method is primarily used for laboratory identification of lymphocyte subsets?

    <p>Flow cytometry</p> Signup and view all the answers

    Which cytokine function is associated with T Regulatory (Treg) cells?

    <p>Inhibiting effector T cell proliferation</p> Signup and view all the answers

    What type of antigen prompts the production of IgM only, and does not generate memory?

    <p>T cell-independent antigens</p> Signup and view all the answers

    What is one role of cytotoxic T cells during the immune response?

    <p>To release perforins and granzymes to destroy target cells</p> Signup and view all the answers

    Which stage of T-cell development occurs after the double positive stage?

    <p>Single Positive (SP)</p> Signup and view all the answers

    What type of antigens stimulate B cells to produce IgM antibodies without T cell help?

    <p>T-independent antigens</p> Signup and view all the answers

    What is the significance of gene rearrangements in T cells?

    <p>They allow for antigen specificity.</p> Signup and view all the answers

    Which specific markers are associated with B cells?

    <p>CD19 and surface immunoglobulins</p> Signup and view all the answers

    What is the role of Class II MHC proteins in B-cell functionality?

    <p>To interact with T helper cells in antibody production</p> Signup and view all the answers

    During B cell development, where does the antigen-independent phase occur?

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

    Study Notes

    Chapter 1: Introduction to Immunity and the Immune System

    • PowerPoints are general overviews for note-taking during video lectures only.
    • PowerPoints do not contain the details needed for exams.
    • Students are responsible for reading the textbook to understand the details required to meet unit objectives.
    • The unit objectives serve as the study guide.
    • Textbook details, not the PowerPoint, are the source of exam questions.

    Chapter Overview

    • Immunity and immunization, including innate vs. adaptive immunity
    • Cells of the innate immune system
    • Cells of the adaptive immune system
    • Organs of the immune system

    Immunology

    • Study of a host's reaction to foreign substances (antigens).
    • Antigens: Foreign substances that induce a host response (e.g., pollen proteins, bacterial components).
    • Immunity: State of being resistant to infection.
    • Attenuation: Making a pathogen less virulent by heat, aging, or chemical means.

    Historical Attempts to Induce Immunity

    • Early methods included inhaling smallpox scab powder (variolation).
    • Dr. Edward Jenner developed the smallpox vaccine from cowpox (vaccination).
    • Dr. Louis Pasteur developed vaccines through attenuation, making pathogens less virulent.

    Innate Immunity

    • Also known as natural immunity.
    • Ability to resist infection through normally present body functions.
    • Nonspecific responses for all pathogens/foreign substances.
    • Prior exposure not required.
    • Effect is immediate; no memory generated.

    Adaptive Immunity

    • Characterized by specificity for each antigen.
    • Memory generated; the immune system "remembers" prior exposure with a heightened response to repeated exposure.

    Cells of the Immune System

    • Leukocytes (white blood cells, WBCs), found in blood and lymphoid tissues.
    • Key roles in innate and adaptive immunity.
    • Types: neutrophils, eosinophils, basophils, monocytes, macrophages, mast cells, dendritic cells, and lymphocytes.

    Cells of the Innate Immune System

    • Polymorphonuclear cells (PMNs): neutrophils, eosinophils, basophils
    • Monocytes/macrophages
    • Mast cells
    • Dendritic cells

    Neutrophils

    • Comprise 50-70% of WBCs in peripheral blood.
    • Primary function is phagocytosis (engulfing) and destroying foreign particles.
    • First to arrive at the infection site.
    • Diapedesis: Move through blood vessel walls into tissues.
    • Margination and adherence to vessel walls
    • Life span of 5 days.

    Eosinophils

    • Comprise 1-4% of WBCs.
    • Involved in phagocytosis, neutralization of allergic reaction products, killing parasites, and releasing cytokines.

    Basophils

    • Less than 1% of WBCs.
    • Release histamine, ECFA, heparin for allergic reactions.

    Monocytes and Macrophages

    • Monocytes are the largest leukocytes in the blood stream, comprising 2-10%.
    • Monocytes differentiate into macrophages in tissues.
    • Phagocytosis (engulf pathogens and cellular debris).
    • Crucial for antigen presentation to adaptive immune cells.
    • Digestive vacuoles (contain enzymes).

    Mast Cells

    • Resemble basophils but larger, present in tissues.
    • Induce and maintain allergic reactions; release granules during allergic reactions, which causes anaphylactic shock.
    • Enhance and suppress the adaptive immune response.

    Dendritic Cells

    • Have long projections like nerve cell dendrites.
    • Roles in both innate and adaptive immunity.
    • Most potent phagocytic cells
    • Main function: phagocytize antigens and present them to helper T lymphocytes (most effective antigen-presenting cells).

    Cells of the Adaptive Immune System: Lymphocytes

    • Lymphocytes (B cells, T cells, NK cells): 20-40% of circulating WBCs.
    • B cells produce antibodies; mature in bone marrow.
    • T cells help with cell-mediated immunity, mature in the thymus.
    • NK cells kill infected and cancerous cells without previous exposure.

    B Cells and Plasma Cells

    • Major role in antibody production.
    • Mature in the bone marrow.
    • Differentiate into plasma cells after contacting antigens.
    • Plasma cells secrete antibodies.

    T Cells

    • Mature in the thymus.
    • Different subtypes with distinct functions: helper T cells (Th), regulatory T cells (Treg), and cytotoxic T cells (Tc).

    Innate Lymphoid Cells and Natural Killer (NK) Cells

    • Important roles in innate immunity and tissue remodeling.
    • NK cells: large granular cells; kill virus-infected cells and tumor cells without prior exposure; destroy antibody-coated target cells.

    Organs of the Immune System

    • Primary lymphoid organs: bone marrow, thymus
    • Secondary lymphoid organs: spleen, lymph nodes, MALT, CALT

    Spleen

    • Largest secondary lymphoid organ.
    • Upper left quadrant of abdomen.
    • Red pulp: rich in macrophages; destroys old red blood cells (RBCs).
    • White pulp: contains lymphoid tissue; contains antigen-stimulated B cells and T cells.

    Lymph Nodes

    • Located along lymphatic ducts.
    • Collect lymph fluid.
    • Lymphocytes and foreign antigens enter via afferent lymphatic vessels.
    • Secondary follicles: proliferating B cells.
    • Location for transformation of B cells, forming plasma cells and memory cells.
    • T cells primarily in the paracortex.

    MALT and CALT

    • Mucosal-associated lymphoid tissue (MALT) found on mucosal surfaces; important entry point for foreign antigens.
    • Cutaneous-associated lymphoid tissue (CALT) found on skin.

    Summary

    • Innate immunity: the body's ability to resist infection through nonspecific body functions.
    • Adaptive immunity: characterized by specificity, memory, and dependence on lymphocytes.
    • All blood cells arise from hematopoietic stem cells.

    Postamble

    • Emphasizes the importance of the textbook for detailed answers to unit objectives.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Clinical Immunology & Serology Chapter 1 PDF
    Innate Immunity Chapter 2 PDF
    U1 Ch3 - Antigens and MHC PDF
    Adaptive Immunity Chapter 4 PDF

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser