Lymphatic System and Body Defenses

Question 1

Forms mechanical barrier that prevents entry of pathogens and other harmful substances into body.

Answer 1

Intact skin (epidermis)

Question 2

Propel debris-laden mucus away from lower respiratory passages.

Answer 2

Cilia

Question 3

Provides resistance against acids, alkalis, and bacterial enzymes.

Answer 3

Keratin

Question 4

Form mechanical barrier that prevents entry of pathogens.

Answer 4

Intact mucous membranes

Question 5

Systemic response triggered by pyrogens; high body temperature
inhibits multiplication of bacteria and enhances body repair
processes.

Answer 5

Fever

Question 6

Filter and trap microorganisms and other airborne particles in nasal passages

Answer 6

Nasal hairs

Question 7

Traps microorganisms in respiratory and digestive tracts.

Answer 7

Mucus

Question 8

Group of plasma proteins that lyses microorganisms, enhances phagocytosis by opsonization, and intensifies inflammatory response.

Answer 8

Complement

Question 9

Normally acid pH inhibits bacterial growth; urine cleanses the lower urinary tract as it flushes from the body.

Answer 9

Fluids with acid pH

Question 10

Promote cell lysis by direct cell attack against virus-infected or
cancerous body cells; do not depend on specific antigen recognition.

Answer 10

Natural killer cells

Question 11

Continuously lubricate and cleanse eyes (tears) and oral cavity
(saliva); contain lysozyme, an enzyme that destroys microorganisms.

Answer 11

Lacrimal secretion (tears); saliva

Question 12

Inhibits growth of bacteria and fungi in female reproductive tract.

Answer 12

Acid mantle of vagina

Question 13

Skin secretions make epidermal surface acidic, which inhibits
bacterial growth; sebum also contains bacteria-killing chemicals.

Answer 13

Acid mantle

Question 14

Engulf and destroy pathogens that breach surface membrane
barriers; macrophages also contribute to immune response.

Answer 14

Phagocytes

Question 15

Contains concentrated hydrochloric acid and protein-digesting
enzymes that destroy pathogens in stomach

Answer 15

Gastric juice

Question 15

Contains concentrated hydrochloric acid and protein-digesting
enzymes that destroy pathogens in stomach

Answer 15

Gastric juice

Question 16

Proteins released by virus-infected cells that protect uninfected tissue cells from viral takeover; mobilize immune system.

Answer 16

Interferons

Question 17

Attached to B cell; free in plasma

Answer 17

IgM

Question 18

When bound to B cell membrane,
serves as antigen receptor; first
Ig class released by plasma
cells during primary response;
potent agglutinating agent; fixes
complement.

Answer 18

IgM

Question 19

Most abundant antibody in
plasma; represents 75–85%
of circulating antibodies

Answer 19

IgG

Question 20

Some (monomer) in plasma;
dimer in secretions such as
saliva, tears, intestinal juice,
and milk

Answer 20

IgA

Question 21

Believed to be cell surface receptor
of immunocompetent B cell;
important in activation of B cell.

Answer 21

IgD

Question 22

Secreted by plasma
cells in skin, mucosae
of gastrointestinal and
respiratory tracts, and tonsils

Answer 22

IgE

Question 23

Binds to mast cells and basophils
and triggers release of histamine
and other chemical mediators of
inflammation and some allergic
responses.

Answer 23

IgE

Question 24

Main antibody of both primary and secondary responses; crosses placenta and provides passive immunity to fetus; fixes complement

Answer 24

IgG

Question 25

Bathes and protects mucosal surfaces from attachment of pathogens.

Answer 25

IgA

Question 26

Believed to be cell surface receptor of immunocompetent B cell; important in activation of B cell.

Answer 26

IgD

Question 27

Group of bloodborne proteins activated after binding to antibody-covered antigens; when activated, complement causes lysis of the microorganism and enhances inflammatory response.

Answer 27

Complement

Question 28

Protein produced by a B cell or its plasma-cell offspring and released into body fluids (blood, lymph, saliva, mucus, etc.), where it attaches to antigens, causing neutralization, opsonization, precipitation, or agglutination, which “marks” the antigens for destruction by phagocytes or complement.

Answer 28

Antibody (immunoglobulin)

Question 29

Chemicals released by sensitized T cells, macrophages, and certain other cells:

Answer 29

Cytokines

Question 30

inhibits” macrophage migration and keeps them in the local area.

Answer 30

Migration inhibiting factor (MIF)—”

Question 31

Helper factors

Answer 31

enhance antibody formation by plasma cells.

Question 32

stimulates T cells and B cells to proliferate; activates NK cells.

Answer 32

Interleukin 2—

Question 33

suppress antibody formation or T cell–mediated immune responses (interleukin-10 transforming growth factor and others).

Answer 33

Suppressor factors—

Question 34

—secreted by lymphocytes; helps make tissue cells resistant to viral infection; activates macrophages and NK cells; enhances maturation of cytotoxic T cells.

Answer 34

Gamma interferon—

Question 35

attract leukocytes (neutrophils, eosinophils, and basophils) into inflamed area.

Answer 35

Chemotactic factors—

Question 36

Like perforin, causes cell killing; attracts granulocytes; activates T cells and macrophages.

Answer 36

Tumor necrosis factor (TNF)

Question 37

Slows or stops the activity of B and T cells once the infection (or attack by foreign cells) has been conquered. Thought to be important in preventing autoimmune diseases.

Answer 37

Regulatory T cell

Question 38

A T cell that binds with a specific antigen presented by an APC; it stimulates the production of other immune cells (cytotoxic T cells and B cells) to help fight the invader; acts both directly and indirectly by releasing cytokines.

Answer 38

Helper T cell

Question 39

Antibody-producing “machine”; produces huge numbers of the same antibody (immunoglobulin); specialized B cell clone descendant.

Answer 39

Plasma cell

Question 40

Lymphocyte that resides in the lymph nodes, spleen, or other lymphoid tissues, where it is induced to replicate by antigen-binding and helper T cell interactions; its progeny (clone members) form plasma cells and memory cells.

Answer 40

B cell

Question 41

Activity enhanced by helper T cells; its specialty is killing virus-invaded body cells, as well as body cells that have become cancerous; involved in graft rejection.

Answer 41

Cytotoxic T cell

Question 42

Any of several cell types (macrophage, dendritic cell, B cell) that engulfs and digests antigens that it encounters and presents parts of them on its plasma membrane for recognition by T cells bearing receptors for the same antigen; this function, antigen presentation, is essential for normal cell-mediated responses. Macrophages and dendritic cells also release chemicals (cytokines) that activate many other immune cells.

Answer 42

Antigen-presenting cell (APC)

Question 43

Descendant of an activated B cell or T cell; generated during both primary and secondary immune responses; may exist in the body for years thereafter, enabling it to respond quickly and efficiently to subsequent infections or meetings with the same antigen.

Answer 43

Memory cell

Question 44

Substance capable of provoking an immune response; typically a large, complex molecule not normally present in the body.

Answer 44

Antigen

Question 45

Perforin, granzymes—cell toxins released by cytotoxic T cells and NK cells.

Answer 45

Cytotoxins

Question 46

chief antibody ammunition used against cellular antigens

Answer 46

Complement fixation

Question 47

cross-linking reaction in which antigen-antibody complex settles out of solution

Answer 47

Precipitation:

Question 48

antibody-antigen reaction that causes clumping of cells

Answer 48

Agglutination:

Question 48

antibodies bind to specific sites on bacterial exotoxins or on viruses that can cause cell injury

Answer 48

Neutralization