Missed Ch. 21: The Immune System

Select the correct statement about complement. A) An adaptive immune mechanism is often involved in directing complement to its target. B) Complement can be activated through three pathways: classical, secondary, and alternate. C) The membrane attack complex consists of complement proteins C3a through C5. D) Complement proteins C1 through C9 act exclusively in the classical pathway.

A) An adaptive immune mechanism is often involved in directing complement to its target.

What is the role of interferon in defense against disease? A) protects cells that have not yet been infected by viruses B) protects cells that have not yet been infected by bacteria C) activates the complement mechanism D) activates the inflammatory process

A) protects cells that have not yet been infected by viruses

Which of the statements below does not describe antigens? A) Antigens exhibit immunogenicity and reactivity. B) Antigens only come from microbes. C) The parts of antigen molecules that initiate immune responses are called epitopes or antigenic determinants. D) Antigens can include proteins, nucleic acids, lipoproteins, glycoproteins, and certain large polysaccharides.

B) Antigens only come from microbes

15) Select the correct statement about lymphocytes. A) The two main types are T cells and macrophages. B) B cells produce plasma cells, which secrete antibodies into the blood. C) T cells are the precursors of B cells. D) T cells are the only form of lymphocyte found in lymphoid tissue.

B) B cells produce plasma cells, which secrete antibodies into the blood.

Which of the following is not a mechanism for the development of autoimmune disorders? A) exposure of previously "hidden" self-antigens to the adaptive immune system B) a second exposure to an allergen C) mutation followed by the appearance of membrane proteins not previously present D) cross-reaction of antibodies formed against foreign antigens with self-antigens

B) a second exposure to an allergen

Which of the following is not a method by which antibodies work? A) neutralizing antigen B) activating cytokines C) enhancing phagocytosis D) agglutinating and precipitating antigen

B) activating cytokines

Antibody functions include all of the following except ________. A) binding and inactivating chemical toxins released by bacteria or other microorganisms B) cross-linking cell-bound antigens on red blood cells when blood types are properly matched C) linking soluble antigens together so that they fall out of solution D) targeting foreign cells so that complement proteins can cause cellular lysis

B) cross-linking cell-bound antigens on red blood cells when blood types are properly matched

Which of the following cells is the most critical cell in immunity? A) B cell B) helper T cell C) cytotoxic T cell D) APC

B) helper T cell

Immunocompetence ________. A) occurs in one specific organ of the adaptive immune system B) is the ability of individual cells to recognize a specific antigen by binding to it C) prevents intercellular communication so that only specific cell types respond to the invader D) requires exposure to an antigen

B) is the ability of individual cells to recognize a specific antigen by binding to it

11) By secreting hormones, the thymus causes what cells to become immunocompetent? A) basophils B) lymphocytes C) macrophages D) monocytes

B) lymphocytes

9) Antibodies that act against a particular foreign substance are released by ________. A) T lymphocytes B) plasma cells C) lymph nodes D) medullary cords

B) plasma cells

Clonal selection of B cells ________. A) occurs during fetal development B) results in the formation of plasma cells C) cannot occur in the presence of antigens D) only occurs in the secondary immune response

B) results in the formation of plasma cells

Which of the following statements is a false or incorrect statement? A) The lymphoid organs where lymphocytes become immunocompetent are called primary lymph organs. All other lymphoid organs are referred to as secondary lymphoid organs. B) It is our genes, not antigens, that determine what specific foreign substances our immune system will be able to recognize and resist. C) After becoming immunocompetent, the naive T cells and B cells are exported to the bone marrow where the encounters with antigens occur. D) T cells and B cells become fully immunocompetent when they bind with recognized antigens.

C) After becoming immunocompetent, the naive T cells and B cells are exported to the bone marrow where the encounters with antigens occur.

Regulatory T cells ________. A) release cytokines that increase the activity of cytotoxic T cells and activated B cells B) decrease their activity as antigenic stimulus decreases C) may function in preventing autoimmune reactions D) are the most thoroughly understood T cells

C) may function in preventing autoimmune reactions

Select the correct statement about active and passive immunity. A) Immunological memory is established by passive immunization. B) A vaccination is an example of the introduction of passive immunity into the body. C) The antibodies utilized in active immunity are acquired from another organism. D) Active and passive humoral immunity are both mechanisms of adaptive immunity that use antibodies.

D) Active and passive humoral immunity are both mechanisms of adaptive immunity that use antibodies.

B cells respond to the initial antigen challenge by ________. A) reducing its size B) immediately producing antigen-specific antibodies C) forming of a large number of cells that are unlike the original B cell D) producing progeny cells that include plasma cells and memory cells

D) Producing progeny cells that include plasma cells and memory cells

Helper T cells ________. A) bind tightly to target cells and release a lymphotoxin called perforin B) often function to decrease the immune response C) release B7 proteins D) function in the adaptive immune system activation

D) function in the adaptive immune system activation

Which of the following does not respond to cell-mediated immunity? A) intracellular pathogens that reside within host cells B) some cancer cells C) foreign tissue transplants D) pathogens in the CNS

D) pathogens in the CNS

Innate immune system defenses include ________. A) B cells B) T cells C) plasma cells D) phagocytosis

D) phagocytosis