Ch. 21 The Immune System

What constitutes the body’s first line of defense against disease?

Intact skin and mucous membranes

Treatment of an abscess often requires that it be surgically drained because ______.

the wall of the abscess prevents neutrophils from entering the pus and attacking the pathogens

Which of the following is NOT a nonspecific internal defense against disease?

T cells

Which defense mechanism results in redness, heat, pain, and swelling?

Inflammation

Which antimicrobial protein is produced by a virus-infected cell?

Interferon

Which of the following is (are) NOT a part of the innate immune defenses?

T Cells

Proinflammatory signals include all of the following, EXCEPT __________.

Antibodies

__________ is the final step of phagocyte mobilization.

Chemotaxis

Which of the following is a role of interferons (IFNs)?

IFNs help the body combat viral infections.

Which of the following is an effect of complement activation?

opsonization

Pyrogens induce __________.

Fever

[T/F]Fever is one of the cardinal signs of inflammation.

False

With what does our immune system coat pathogens to facilitate their capture and accelerate phagocytosis?

opsonins

Four (or five) cardinal signs indicate inflammation. What specific sign of inflammation is the result of exudate in the tissue spaces?

Edema (Swelling)

Which of the following inflammatory chemicals is released by mast cells?

Histamine

Which of the following is NOT one of the cardinal signs of inflammation?

Vasoconstriction

When do neutrophils enter the blood from the red bone marrow, in response to leukocytosis-inducing factors?

leukocytosis

What is the main event of chemotaxis?

Neutrophils and other WBCs migrate up the gradient of chemotactic agents to the site of injury.

Neutrophils flatten and squeeze between the endothelial cells of the capillary walls during what process?

Diapedesis

What protein can be released by infected cells to help protect cells that have not yet been infected?

Interferons

How do interferons protect against infection in healthy cells?

Interferons block viral reproduction in healthy cells through the production of antiviral proteins.

What is the specific target of interferons?

nearby healthy cells

What types of antigen are recognized by T cells?

processed fragments of protein antigens displayed on surfaces of body cells

[T/F]MHC I proteins (major histocompatibility class I proteins) are found on most cells of the body.

True

Which of the following statements does NOT describe the adaptive immune response?

It occurs immediately after the body is challenged by foreign material.

What mobilizes the adaptive defenses and provokes an immune response?

Antigens

Which of the following cells engulf antigens and present fragments of them on their own surfaces, where they can be recognized by cells that will deal with them?

Dendritic cells

T cells achieve self-tolerance in the __________.

Thymus

Which cells mature in the thymus?

T Cells

How does a lymphocyte become immunocompetent?

Lymphocytes must be able to recognize their one specific antigen by binding to it.

What are B and T cells called that have not yet been exposed to an antigen?

Naive

Binding of an eosinophil to an antibody-coated parasitic worm involves binding of the antibody’s stem region to a(n) ______.

plasma membrane protein on the eosinophil’s surface

Why are children given vaccinations?

to develop antibodies against various diseases

Choose the true statement regarding the primary versus the secondary immune response.

A primary response results when naïve lymphocytes are activated, while a secondary response is a result of activating memory cells.

__________ immunity protects a baby who is fed breast milk.

Natural Passive

__________ is the most abundant class of antibodies in plasma.

IgG

__________ are lymphocytes that directly kill virus- infected cells.

Cytotoxic T cells

Antigens bound to MHC II activate __________.

Helper T cells

How would you classify the antivenom used to treat poisonous snake bites?

passive immunity, artificially acquired

Which of the following exemplifies passive immunity?

Antitoxin

Which of the following best illustrates artificially acquired active humoral immunity?

Vaccine

What part of the antibody’s structure determines its class?

constant (C) region

Which immunoglobulin class can cross the placenta to provide naturally acquired passive immunity to the fetus?

IgG

What is the first antibody released in the primary response and usually indicates infection?

IgM

What mechanism occurs when antibodies block specific sites on viruses or bacterial exotoxins?

Neutralization

When of the following mechanisms of antibody action occur when red blood cells clump due to a transfusion of mismatched blood?

agglutination

Which mechanism of antibody action results in cell lysis?

Complete fixation and activation

Which cell of the immune system is absolutely required for an adaptive immune response in that it helps activate both humoral and cellular immune responses?

helper T cell

Which of the following is NOT a characteristic of Natural Killer (NK) cells?

NK cells recognize abnormal or cancer cells by a specific antigen on their cell membrane

Which of the following innate internal defenses work by interfering with viral replication?

Interferons

How do phagocytes recognize foreign cells or bacteria?

The phagocytes recognize molecules on pathogens not normally found on body cells.

Which of the innate defense mechanisms can lyse bacteria and mark cells for phagocytosis?

Complement proteins

Which of the following can act as opsonins on bacteria, thus enhancing phagocytosis?

Antibodies and complement proteins

Tears and mucus membranes would be a part of which defense system?

innate external defenses

Phagocytotic cells such as macrophages identify a variety of enemies by recognizing markers unique to pathogens. They would be classified as which type of defense system?

Innate internal defenses

What cells make antibodies?

Plasma B cells

What is the name of the unique area (specific region) that a lymphocyte recognizes and binds to?

an antigenic determinant

What type of immunity can be transferred by bodily fluids from one person to another, thus conferring immunity to the recipient?

Humoral Immunity

If a virus attacks a cell, which type of immunity would be activated?

Cell-Mediated Immunity (Cellular Immunity)

Cancer cells would be attacked by which of the following cells?

Cytotoxic T cells

Class II MHC proteins are found on which of the following cell types?

Antigen-Presenting Cells

Which class of MHC proteins presents exogenous antigens?

Class ll MHC Proteins

Class I MHC proteins are recognized by which of the following cell types (that are destined to become T cells)?

CD8

Which of the following types of cells display protein fragments produced by the cancer within them?

All nucleated cells

Which major class of lymphocytes become cytotoxic T cells?

CD8 Cells

Cellular immunity is attributed to the action of __________.

T Cells

Which of the following do NOT serve as antigen-presenting cells (APC)?

Natural Killer Cells

What occurs if a T cell binds to an antigen and the T cell does NOT receive a co-stimulatory signal?

The T cell enters a state of anergy.

__________ are lymphocytes that coordinate cellular and humoral immune responses.

Helper T cells

What type of cell is the precursor to the helper T cell?

CD4 Cell

What type of cell is a precursor to the cytotoxic T cell?

CD8 Cell

What activates CD8 cells?

antigen fragments on class I MHC proteins

What type of T cell can directly attack and kill other cells, such as virus-infected cells?

Cytotoxin T Cell

Cytotoxic T (TC) cells check cells of the body for identity flags to see if they look they way they are supposed to. What is this process called?

Immune surveillance

Which type of T cell will recognize antigens associated with an allograft?

Cytotoxin T Cell

Which class of tissue graft is the least likely to be accepted by a patient’s body?

Xenograft

Which of the following are mismatched?

immediate hypersensitivity: allergic contact dermatitis

[T/F]Cellular ingestion and destruction of particulate matter is called phagocytosis.

True

[T/F]The respiratory burst produced by some macrophages releases free radicals.

True

[T/F]The directional movement of cells in response to chemicals is called chemotaxis.

True

[T/F]Fever is seldom beneficial because it speeds up the cellular metabolic rate and will not allow antigen-antibody reactions to occur.

False

Which of the following is not a function of the inflammatory response?

replaces injured tissues with connective tissue

Which of the following statements regarding NK cells is a false or incorrect statement?

NK cells are a type of neutrophil.

The process whereby neutrophils and other white blood cells are attracted to an inflammatory site is called ________.

chemotaxis

Which of the following is the correct sequence of events in phagocytosis?

chemotaxis, adherence, ingestion, digestion, killing

Interferons ________.

interfere with viral replication within cells

Which of the following is a part of the second line of defense against microorganisms?

Phagocytes

Cancer cells and virus-infected body cells can be killed before activation of adaptive immunity by ________.

natural killer cells

Complement proteins and antibodies coat a microorganism and provide binding sites, enabling macrophages and neutrophils to phagocytize the organism. This phenomenon is termed ________.

opsonization

Innate immune system defenses include ________.

phagocytosis

Phagocyte mobilization involves ________.

mainly neutrophil and macrophage migration into inflamed areas

Fever ________.

production is regulated by chemicals that reset the body’s thermostat to a higher setting

Natural killer (NK) cells ________.

can kill cancer cells before the immune system is activated

What is the role of interferon in defense against disease?

protects cells that have not yet been infected by viruses

A physician orders Tylenol for a temperature greater than 101 degrees F. The patient’s temperature is 100.4 F. What is the rationale for not medicating a fever of 100.4 F?

A mild or moderate fever is an adaptive response that seems to benefit the body. Bacteria need large amounts of zinc and iron to multiply. During fever, the liver and spleen sequester iron and zinc that bacteria need to multiply.

When the white blood cell count is depressed, the classic signs of infection such as redness, local heat, and swelling are not manifested. In this case, should the nurse avoid administering aspirin?

Yes, aspirin should be avoided because aspirin would disguise a fever that would indicate infection.

[T/F]Virus infected cells secrete complement to "warn" other cells of the presence of virus.

False

[T/F]The classical complement pathway involves antibodies.

True

Which of the following is not a role of activated complement?

prevention of immediate hypersensitivity reactions

Which of the following cells predominate at the sites of chronic infections?

Macrophages

Which of the following is not a complement activation pathway?

lactate pathway

[T/F]Substances capable of triggering the adaptive immune system and provoking an immune response are called antigens.

True

Small molecules that bind with self-proteins to produce antigenic substances are called ________.

haptens

Which of the following is characteristic of complete antigens?

reactivity with an antibody

Which of the following is not characteristic of the adaptive immune system?

It is specific for a given organ.

Which of the following statements is incorrect or false?

Class II MHC molecules appear only on the surface of antigen-presenting cells, thymic cells, and T cells that have been activated by exposure to antigens

Immunocompetence ________.

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

Select the correct statement about antigens.

One antigen may have many different antigenic determinants and may therefore cause the formation of more than one antibody.

[T/F]Some immunocompetent cells will never be called to service in our lifetime.

True

[T/F]Adaptive immunity is provided only by lymphocytes that secrete antibodies.

False

[T/F]Somatic recombination by B cells allows each B cell to form its own unique antibody genes.

True

[T/F]It is our genes, not antigens, that determine what specific foreign substances our immune system will be able to recognize and resist.

True

B lymphocytes develop immunocompetence in the ________.

Bone Marrow

Which of the statements below does not describe antigens?

Antigens only come from microbes.

Which of the following determine(s) what specific foreign substances our adaptive immune system will be able to recognize and resist?

Our genes

Which of the following statements is a false or incorrect statement?

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

[T/F]Soluble proteins secreted by plasma cells are called antibodies.

True

Which of the following is characteristic of antibodies?

Composed of heavy and light polypeptide chains

Which of the following is associated with passive immunity?

passage of IgG antibodies from a pregnant mother to her fetus

The antibody molecule is held together by ________ bonds.

Disulfide

In clonal selection of B cells, which substance is responsible for determining which cells will eventually become cloned?

antigen

B cells respond to the initial antigen challenge by ________.

producing progeny cells that include plasma cells and memory cells

Select the correct statement about active and passive immunity.

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

Clonal selection of B cells ________.

results in the formation of plasma cells

The primary immune response ________.

has a lag period while B cells proliferate and differentiate into plasma cells

Select the correct statement about the function of antibodies.

Complement fixation is the main mechanism by which antibodies provide protection.

Antibody functions include all of the following except ________.

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

[T/F]Antibodies cn act both intracellularly and extracellularly.

True

Monoclonal antibodies are used for the diagnosis of all of the following except ________.

Juvenile Diabetes

Which of the following is not a method by which antibodies work?

Direct cell lysis

Which immunoglobulin class is attached to the external surface of B cells and acts as an antigen receptor of the B cell?

IgD

[T/F]The mechanism of the "lethal hit" of cytotoxic T cells and NK cells involves a protein called perforin.

True

[T/F]A given pathogen will provoke either a cell-mediated response or an antibody-mediated response but not both.

True

[T/F]Monoclonal antibodies can be specific for several antigenic determinants.

False

[T/F]Both T cells and B cells must accomplish double recognition: They must simultaneously recognize self and nonself to be activated.

True

Which of the following is not a type of T cell?

Antigenic

Select the correct definition about tissue grafts.

Isografts are between identical twins

Cytotoxic T cells ________.

are the only T cells that can directly attack and kill other cells

Helper T cells ________.

function in the adaptive immune system activation

Which of the following cells is the most critical cell in immunity?

Helper T cell

Which statement is true about T cells?

Their proliferation is enhanced by interleukins 1 and 2.

Which of the following does not respond to cell-mediated immunity?

Pathogens in the lumen of the stomach

Regulatory T cells ________.

may function in preventing autoimmune reactions

Activated T cells and macrophages release ________ to mobilize immune cells and attract other leukocytes into the area.

Cytokines

T-cell activation requires ________.

antigen binding and co-stimulation

[T/F]Anaphylactic shock can result from an immediate hypersensitivity where the allergen enters the blood.

True

[T/F]A transfusion reaction is a subacute hypersensitivity to foreign red blood cells.

True

Which of the following would be classified as a delayed hypersensitivity reaction?

allergic contact dermatitis

Select the correct statement about immunodeficiency.

The causative agent in acquired immune deficiency syndrome (AIDS) is a virus that recognizes CD4 proteins.

Delayed hypersensitivities ________.

include allergic contact dermatitis

Which of the following is not an autoimmune disease?

type II diabetes

Which of the following is not a mechanism for the development of autoimmune disorders?

A second exposure to an antigen

A 36-year-old man enters the hospital in an extremely debilitated condition. He has purple-brown skin lesions (a symptom of Kaposi’s sarcoma) and a persistent cough. A physical examination reveals swollen lymph nodes, and laboratory tests find a very low lymphocyte count. Information taken during the personal history reveals that he has multiple sex partners with whom he frequently engages in unprotected sex. What is likely to be the man’s problem and what is his prognosis?

He is probably suffering from AIDS. His outlook is poor once the disease has progressed to this advanced stage. There is no cure, and drug therapy has had limited short-term success.

Which of the following is true of immediate hypersensitivities?

They involve IgE antibodies and the release of histamine from mast cells and basophils.

Select the correct statement about the prevention of immune attack on "self."

Tolerance is developed during fetal life.