Ch. 21 Lymphatic and Immune System Flashcards
Which structure allows lymph from the lower right limb to enter the bloodstream?
A) Thoracic duct
B) Right lymphatic duct
C) Right lymphatic trunk
D) Left lymphatic trunk
A) Thoracic duct.
Explanation: The thoracic duct drains lymph from the entire lower body, including the lower right limb, and empties into the left subclavian vein.
Incorrect Answers:
B) Right lymphatic duct: Only drains the upper right quadrant of the body.
C) Right lymphatic trunk: Drains the right side but is not a major duct entering the bloodstream.
D) Left lymphatic trunk: Not a standard anatomical term; likely a distractor.
Which of the lymphoid nodules is most likely to see food antigens first?
A) Tonsils
B) Peyer’s patches
C) Bronchus-associated lymphoid tissue
D) Mucosa-associated lymphoid tissue
Correct Answer: A) Tonsils.
Explanation: Tonsils are located at the entrance to the pharynx and are the first lymphoid tissue to encounter foodborne pathogens.
Incorrect Answers:
B) Peyer’s patches: Located in the small intestine; encounter food antigens later.
C) Bronchus-associated lymphoid tissue: Monitors airborne—not ingested—pathogens.
D) Mucosa-associated lymphoid tissue: A general term, not specific to early exposure to food antigens.
Which of the following cells is phagocytic?
A) Plasma cell
B) Macrophage
C) B cell
D) NK cell
B) Macrophage.
Explanation: Macrophages are professional phagocytes that ingest and digest cellular debris and pathogens.
Incorrect Answers:
A) Plasma cell: Produces antibodies but does not perform phagocytosis.
C) B cell: Recognizes antigens and differentiates into plasma cells, but is not phagocytic.
D) NK cell: Kills abnormal cells through cytotoxic mechanisms, not phagocytosis.
Which of the following cells is important in the innate immune response?
A) B cells
B) T cells
C) Macrophages
D) Plasma cells
C) Macrophages.
Explanation: Macrophages are part of the innate immune system and respond quickly to pathogens by engulfing them and releasing inflammatory signals.
Incorrect Answers:
A) B cells: Part of the adaptive immune response.
B) T cells: Also adaptive and require antigen presentation.
D) Plasma cells: Antibody-producing cells derived from B cells—adaptive immunity.
Which of the following cells would be most active in early, antiviral immune responses the first time one is exposed to a pathogen?
A) Macrophage
B) T cell
C) Neutrophil
D) Natural killer cell
D) Natural killer cell.
Explanation: NK cells are part of the innate immune system and can destroy virus-infected cells quickly, even without prior exposure.
Incorrect Answers:
A) Macrophage: Active in general pathogen removal, but less specific to viral responses.
B) T cell: Requires antigen presentation and clonal expansion, so it acts later.
C) Neutrophil: More active in bacterial than viral infections.
Which of the following signs is not characteristic of inflammation?
A) Redness
B) Pain
C) Cold
D) Swelling
C) Cold.
Explanation: The hallmark signs of inflammation are redness, heat, swelling, pain, and sometimes loss of function. Cold is not one of them.
Incorrect Answers:
A) Redness: Caused by increased blood flow.
B) Pain: Result of chemical mediators stimulating nerves.
D) Swelling: Due to increased permeability and fluid accumulation.
Which of the following is not important in the antiviral innate immune response?
A) Interferons
B) Natural killer cells
C) Complement
D) Microphages
D) Microphages.
Explanation: “Microphages” is not a standard term used in immunology. The question likely uses this term as a distractor. True innate immune antiviral responses rely on interferons, NK cells, and complement.
Incorrect Answers:
A) Interferons: Proteins secreted by virus-infected cells that inhibit viral replication.
B) Natural killer cells: Kill virus-infected cells quickly without prior sensitization.
C) Complement: Helps lyse virus-infected cells and mark them for immune clearance.
Enhanced phagocytosis of a cell by the binding of a specific protein is called (BLANK).
A) Endocytosis
B) Opsonization
C) Anaphylaxis
D) Complement activation
B) Opsonization.
Explanation: Opsonization refers to coating pathogens with proteins (like antibodies or complement) to make them easier for phagocytes to recognize and engulf.
Incorrect Answers:
A) Endocytosis: General cellular uptake process, not specific to immune enhancement.
C) Anaphylaxis: Severe allergic reaction, unrelated to phagocytosis.
D) Complement activation: Part of the immune response but not specific to enhancing phagocytosis unless it leads to opsonization.
Which of the following leads to the redness of inflammation?
A) Increased vascular permeability
B) Anaphylactic shock
C) Increased blood flow
D) Complement activation
C) Increased blood flow.
Explanation: Redness (erythema) in inflammation is due to vasodilation and increased blood flow to the affected tissue.
Incorrect Answers:
A) Increased vascular permeability: Causes swelling, not redness.
B) Anaphylactic shock: A systemic allergic reaction, not a localized inflammation sign.
D) Complement activation: May contribute to inflammation but does not directly cause redness.
T cells that secrete cytokines that help antibody responses are called (BLANK).
A) Th1
B) Th2
C) Regulatory T cells
D) Thymocytes
B) Th2.
Explanation: Th2 cells support B cell differentiation and antibody production, especially in humoral immunity.
Incorrect Answers:
A) Th1: Promote cell-mediated immunity, not antibody responses.
C) Regulatory T cells: Suppress immune responses, do not enhance antibody production.
D) Thymocytes: Immature T cells found in the thymus.
The taking in of antigen and digesting it for later presentation is called (BLANK).
A) Antigen presentation
B) Antigen processing
C) Endocytosis
D) Exocytosis
B) Antigen processing.
Explanation: Antigen processing involves digesting the antigen into fragments that can be presented by MHC molecules.
Incorrect Answers:
A) Antigen presentation: Follows antigen processing; it’s the display of the processed antigen on MHC.
C) Endocytosis: The uptake step only, without processing.
D) Exocytosis: Export of materials from a cell, not related to antigen digestion.
Why is clonal expansion so important?
A) To select for specific cells
B) To secrete cytokines
C) To kill target cells
D) To increase the numbers of specific cells
D) To increase the numbers of specific cells.
Explanation: Clonal expansion ensures that once a specific lymphocyte recognizes an antigen, many identical cells are produced to fight the infection.
Incorrect Answers:
A) To select for specific cells: Selection occurs earlier in lymphocyte development, not during expansion.
B) To secrete cytokines: A function of some cells, but not the purpose of clonal expansion.
C) To kill target cells: Only cytotoxic cells do this after expansion.
The elimination of self-reactive thymocytes is called (BLANK).
A) Positive selection
B) Negative selection
C) Tolerance
D) Clonal selection
B) Negative selection.
Explanation: Negative selection removes T cells that bind strongly to self-antigens, preventing autoimmunity.
Incorrect Answers:
A) Positive selection: Ensures T cells can recognize MHC molecules.
C) Tolerance: A broader term; negative selection is one mechanism by which tolerance is achieved.
D) Clonal selection: Describes how lymphocytes are selected after encountering antigen—not part of thymic screening.
Which type of T cell is most effective against viruses?
A) Th1
B) Th2
C) Cytotoxic T cells
D) Regulatory T cells
C) Cytotoxic T cells.
Explanation: Cytotoxic T cells (CD8⁺) directly kill virus-infected cells.
Incorrect Answers:
A) Th1: Help activate cytotoxic cells but don’t kill directly.
B) Th2: Involved in antibody production, less relevant to direct viral killing.
D) Regulatory T cells: Suppress immune responses, not antiviral.
Removing functionality from a B cell without killing it is called (BLANK).
A) Clonal selection
B) Clonal expansion
C) Clonal deletion
D) Clonal anergy
D) Clonal anergy.
Explanation: Clonal anergy is a state where B cells become non-responsive to antigen, often due to lack of T cell help or exposure to self-antigen.
Incorrect Answers:
A) Clonal selection: Selection of B cells that recognize an antigen.
B) Clonal expansion: Proliferation of B cells after activation.
C) Clonal deletion: Involves killing the self-reactive cell.
Which class of antibody crosses the placenta in pregnant women?
A) IgM
B) IgA
C) IgE
D) IgG
D) IgG.
Explanation: IgG is the only class of antibody that can cross the placenta, providing passive immunity to the fetus.
Incorrect Answers:
A) IgM: First antibody produced during infection; too large to cross placenta.
B) IgA: Found in secretions like breast milk, not in the placenta.
C) IgE: Involved in allergies and parasitic responses, not placental transfer.
Which class of antibody has no known function other than as an antigen receptor?
A) IgM
B) IgA
C) IgE
D) IgD
D) IgD.
Explanation: IgD primarily functions as an antigen receptor on naive B cells and has no well-defined role in immune defense.
Incorrect Answers:
A) IgM: First antibody secreted; involved in agglutination and complement activation.
B) IgA: Protects mucosal surfaces, secreted in mucus and other secretions.
C) IgE: Involved in allergic reactions and defense against parasites.
When does class switching occur?
A) Primary response
B) Secondary response
C) Tolerance
D) Memory response
B) Secondary response.
Explanation: Class switching happens after initial exposure, usually during the secondary immune response, allowing B cells to produce different classes of antibodies (e.g., from IgM to IgG, IgA, or IgE).
Incorrect Answers:
A) Primary response: IgM is mostly produced; class switching hasn’t occurred yet.
C) Tolerance: Refers to immune non-responsiveness to self-antigens.
D) Memory response: Benefits from class-switched antibodies, but switching occurs earlier.
Which class of antibody is found in mucus?
A) IgM
B) IgA
C) IgE
D) IgD
B) IgA.
Explanation: IgA is secreted in mucosal areas (saliva, tears, intestinal secretions) and plays a crucial role in mucosal immunity.
Incorrect Answers:
A) IgM: Found mostly in the bloodstream; first antibody secreted.
C) IgE: Involved in allergy, not mucosal defense.
D) IgD: Functions as a B cell receptor, not secreted into mucus.
Which enzymes in macrophages are important for clearing intracellular bacteria?
A) Metabolic
B) Mitochondrial
C) Nuclear
D) Lysosomal
D) Lysosomal.
Explanation: Lysosomal enzymes digest engulfed pathogens within phagosomes after fusion with lysosomes.
Incorrect Answers:
A) Metabolic: Broad term; not specific to pathogen digestion.
B) Mitochondrial: Involved in energy production, not microbial digestion.
C) Nuclear: Related to DNA processes, not bacterial clearance.
What type of chronic lung disease is caused by a Mycobacterium?
A) Asthma
B) Emphysema
C) Tuberculosis
D) Leprosy
C) Tuberculosis.
Explanation: Tuberculosis is caused by Mycobacterium tuberculosis, a chronic bacterial lung infection.
Incorrect Answers:
A) Asthma: Allergic/immune condition, not caused by bacteria.
B) Emphysema: Result of long-term smoking or irritant exposure, not infectious.
D) Leprosy: Also caused by a Mycobacterium (M. leprae), but affects skin and nerves.
Which type of immune response is most directly effective against bacteria?
A) Natural killer cells
B) Complement
C) Cytotoxic T cells
D) Helper T cells
B) Complement.
Explanation: The complement system lyses bacteria and enhances phagocytosis through opsonization.
Incorrect Answers:
A) Natural killer cells: Target virally infected and tumor cells.
C) Cytotoxic T cells: Target virus-infected and abnormal self-cells.
D) Helper T cells: Coordinate the response but don’t act directly on bacteria.
What is the reason that you have to be immunized with a new influenza vaccine each year?
A) The vaccine is only protective for a year
B) Mutation
C) Macrophage oxidative metabolism
D) Memory response
B) Mutation.
Explanation: The influenza virus mutates frequently (antigenic drift), requiring updated vaccines annually.
Incorrect Answers:
A) The vaccine is only protective for a year: Immunity could last longer, but mutations reduce effectiveness.
C) Macrophage oxidative metabolism: Not relevant to vaccine effectiveness.
D) Memory response: Helps long-term immunity, not the reason for yearly updates.
Which type of immune response works in concert with cytotoxic T cells against virally infected cells?
A) Natural killer cells
B) Complement
C) Antibodies
D) Memory
A) Natural killer cells.
Explanation: NK cells and cytotoxic T cells both kill virus-infected cells—NKs act early, T cells act later after antigen presentation.
Incorrect Answers:
B) Complement: More effective against extracellular pathogens like bacteria.
C) Antibodies: Neutralize viruses but don’t kill infected cells.
D) Memory: Important for long-term protection, not a direct mechanism.
Which type of hypersensitivity involves soluble antigen-antibody complexes?
A) Type I
B) Type II
C) Type III
D) Type IV
C) Type III.
Explanation: Type III hypersensitivity results from immune complex deposition in tissues, leading to inflammation (e.g., lupus, serum sickness).
Incorrect Answers:
A) Type I: Involves IgE-mediated allergies (e.g., anaphylaxis).
B) Type II: Antibodies bind to cell surfaces (e.g., blood transfusion reaction).
D) Type IV: Delayed, T cell-mediated response (e.g., poison ivy).
What causes the delay in delayed hypersensitivity?
A) Inflammation
B) Cytokine release
C) Recruitment of immune cells
D) Histamine release
C) Recruitment of immune cells.
Explanation: Type IV hypersensitivity involves activation and recruitment of T cells and macrophages, which takes 24–72 hours.
Incorrect Answers:
A) Inflammation: A result, not the cause of delay.
B) Cytokine release: Happens quickly; delay is from cellular recruitment.
D) Histamine release: Occurs in Type I reactions, not delayed hypersensitivity.
Which of the following is a critical feature of immediate hypersensitivity?
A) Inflammation
B) Cytotoxic T cells
C) Recruitment of immune cells
D) Histamine release
D) Histamine release.
Explanation: Immediate hypersensitivity (Type I) is characterized by rapid release of histamine from mast cells and basophils following IgE binding.
Incorrect Answers:
A) Inflammation: A general result of hypersensitivity, but not its defining immediate feature.
B) Cytotoxic T cells: Involved in Type IV hypersensitivity, not immediate.
C) Recruitment of immune cells: Characteristic of delayed hypersensitivity (Type IV).
Which of the following is an autoimmune disease of the heart?
A) Rheumatoid arthritis
B) Lupus
C) Rheumatic fever
D) Hashimoto’s thyroiditis
C) Rheumatic fever.
Explanation: Rheumatic fever is an autoimmune response following streptococcal infection where the immune system mistakenly attacks heart tissue.
Incorrect Answers:
A) Rheumatoid arthritis: Autoimmune disease of the joints.
B) Lupus: A systemic autoimmune disease affecting multiple organs.
D) Hashimoto’s thyroiditis: Targets the thyroid gland.
What drug is used to counteract the effects of anaphylactic shock?
A) Epinephrine
B) Antihistamines
C) Antibiotics
D) Aspirin
A) Epinephrine.
Explanation: Epinephrine rapidly reverses airway constriction, boosts blood pressure, and counteracts the effects of severe allergic reaction.
Incorrect Answers:
B) Antihistamines: Useful for milder allergies, but too slow for anaphylaxis.
C) Antibiotics: Treat infections, not allergic reactions.
D) Aspirin: Anti-inflammatory but not helpful in anaphylactic shock.
Which of the following terms means “many genes”?
A) Polymorphism
B) Polygeny
C) Polypeptide
D) Multiple alleles
B) Polygeny.
Explanation: Polygeny refers to a trait being controlled by multiple genes, as seen with MHC gene families.
Incorrect Answers:
A) Polymorphism: Refers to multiple variants (alleles) of a gene, not many genes.
C) Polypeptide: A chain of amino acids, not related to genetics.
D) Multiple alleles: Refers to different forms of a single gene.
Why do we have natural antibodies?
A) We don’t know why
B) Immunity to environmental bacteria
C) Immunity to transplants
D) From clonal selection
B) Immunity to environmental bacteria.
Explanation: Natural antibodies arise without prior exposure and provide a first line of defense, especially against environmental bacteria.
Incorrect Answers:
A) We don’t know why: Not accurate; there is evidence for their origin.
C) Immunity to transplants: Natural antibodies are not transplant-specific.
D) From clonal selection: Natural antibodies are generated independently of antigen exposure.
Which type of cancer is associated with HIV disease?
A) Kaposi’s sarcoma
B) Melanoma
C) Lymphoma
D) Renal cell carcinoma
A) Kaposi’s sarcoma.
Explanation: Kaposi’s sarcoma is strongly associated with HIV/AIDS due to reactivation of human herpesvirus 8 (HHV-8) in immunocompromised individuals.
Incorrect Answers:
B) Melanoma: A skin cancer not typically associated with HIV.
C) Lymphoma: Can occur in HIV, but not as specific as Kaposi’s sarcoma.
D) Renal cell carcinoma: Kidney cancer, unrelated to HIV.
How does cyclosporine A work?
A) Suppresses antibodies
B) Suppresses T cells
C) Suppresses macrophages
D) Suppresses neutrophils
B) Suppresses T cells.
Explanation: Cyclosporine A inhibits T cell activation by blocking IL-2 production, preventing transplant rejection.
Incorrect Answers:
A) Suppresses antibodies: This is not its main effect.
C) Suppresses macrophages: Not the primary target of cyclosporine.
D) Suppresses neutrophils: Cyclosporine does not primarily affect neutrophils.
What disease is associated with bone marrow transplants?
A) Diabetes mellitus type I
B) Melanoma
C) Headache
D) Graft-versus-host disease
D) Graft-versus-host disease.
Explanation: GVHD occurs when transplanted donor immune cells attack the recipient’s tissues—common with bone marrow transplants.
Incorrect Answers:
A) Diabetes mellitus type I: An autoimmune disease, not transplant-related.
B) Melanoma: Unrelated to transplants.
C) Headache: A symptom, not a disease associated with bone marrow transplantation.
