Chapter 43: Immune System

Question 1

Pathogens

Answer 1

foreign invaders that try to co-opt organismal resources; cause disease

Question 2

immune system

Answer 2

necessary to avoid/limit infection

Question 3

innate immunity

Answer 3

active all the time, non-specific. Found in all animals and plants

Question 4

acquired immunity

Answer 4

adaptive immunity; enhanced by previous infection, highly specific. Found in vertebrates

Question 5

barrier defenses

Answer 5

skin, mucous membranes, secretions

Question 6

Internal defenses

Answer 6

phagocytic cells, natural killer cells, antimicrobial proteins, inflammatory response

Question 7

humoral response

Answer 7

antibodies defend against infection in body fluids

Question 8

cell-mediated response

Answer 8

cytotoxic cells defend against infection in body cells

Question 9

innate immunity in insects

Answer 9

barrier: waxy chitin exoskeleton
low pH and lysozyme: digest microbes in gut
hemocytes in hemolymph: phagocytosis and various chemical protections
antimicrobial peptides: disrupt pathogen plasma membrane

Question 10

innate immunity in vertebrates

Answer 10

barrier: skin epithelium, mucus coverings over exchange surfaces
lysozyme in saliva, mucus, teats, etc.
sweat lowers skin pH, low stomach pH
toll-like receptors

Question 11

Toll-like receptor (TLR)

Answer 11

receptors that recognize pathogen bits

Question 12

macrophages

Answer 12

white blood cell; phagocytosis engulf and digest microbes

Question 13

interferons

Answer 13

antimicrobial peptide; produced by cells infected by viruses, signal other cells to produce anti-viral compounds

Question 13

complement system

Answer 13

antimicrobial peptide; activated by microbial substances, leads to bursting of cells

Question 13

lymphatic system

Answer 13

organs to trap foreign particles; tonsils, spleen, appendix

Question 14

inflammatory response

Answer 14

release of signaling molecules following infection/injury; causes warmth, swelling, formation of pus

Question 15

mast cells

Answer 15

release histamine; causes vessels to dilate, become more permeable

Question 16

pyrogens

Answer 16

part of systemic inflammatory response; causes localized increase in temperature

Question 17

natural killer cells

Answer 17

can recognize and destroy diseased cells; look for cells that do not produce class I MHC surface proteins and kill them

Question 18

lymphocytes

Answer 18

white blood cells; have an enhanced response to infections the body has previously encountered (immunological memory)

Question 19

B-cells

Answer 19

type of lymphocyte; mature in bone marrow. secrete soluble receptors (antibodies) that bind to foreign molecules

Question 20

T-cells

Answer 20

type of lymphocyte; move from bone to the thymus. detect and kill infected cells or help activate other lymphocytes

Question 21

immunological memory

Answer 21

lymphocytes activate by binding to specific foreign molecule as a response to infections previously encountered

Question 22

antibodies

Answer 22

soluble antigen receptors from b-cells

Question 23

antigens

Answer 23

foreign molecules recognized by lymphocytes; small molecules, parts of large molecules; may be on the surface of pathogens

Question 24

antigen receptors

Answer 24

receptors in plasma membrane of T & B lymphocytes

Question 25

plasma cells

Answer 25

some B lymphocytes that produce soluble antigen receptors (antibodies)

Question 26

epitope

Answer 26

small part of antigen that is recognized by antigen receptor

Question 27

b-cell antigen receptor structure

Answer 27

Y- shaped, two identical heavy chains, 2 identical light changs. each chain has constant (C) and variable (V) regions

Question 28

T-cell receptor structure

Answer 28

alpha and beta chains, constant (C) and variable (V) regions but with 1 antigen binding site

Question 29

MHC

Answer 29

major histocompatibility complex; make proteins that present antigens on cell surface

Question 30

Class I MHC

Answer 30

in almost all cells; bind foreign peptides synthesized in cell, recognized by cytotoxic T cells

Question 31

Class II MHC

Answer 31

in macrophages, B cells, etc (antigen presenting cells), bind foreign fragments acquired through phagocytosis; recognized by helper T cells

Question 32

light chain

Answer 32

composed of 3 regions: variable, joining, constant

Question 33

recombinase

Answer 33

enzyme randomly links a variable to a joining region, increasing variability/options

Question 34

heavy chain

Answer 34

similar to a light chain, but with even more options; variable, joining, and constant regions

Question 35

self tolerance

Answer 35

the self-reactivity of a lymphocyte

Question 36

clonal selection

Answer 36

division of B cells into many memory b cells and plasma cells

Question 37

effector cells

Answer 37

type of daughter cell; short lived, attack antigen/pathogen

Question 38

memory cells

Answer 38

type of daughter cell; long lived, with same antigen receptor

Question 39

humoral immune response

Answer 39

activation and clonal selection of effector B cells; secrete antibodies that circulate in blood and lymph

Question 40

primary immune response

Answer 40

first exposure; production of plasma cells and memory cells which leads to immunological memory

Question 41

secondary immune response

Answer 41

second exposure; faster response, relies on increased numbers after first exposure

Question 42

helper T-cells

Answer 42

enhance humoral and cell-mediated responses; stimulates B cells and cytotoxic T cells

Question 43

cytotoxic T-cells

Answer 43

effector T cells; secretes proteins that rupture cell membrane

Question 44

activation of B cells

Answer 44

requires interaction with helper T cells

Question 45

neutralization

Answer 45

antibodies bind to virus, bacterium or toxin to interfere with pathogen function

Question 46

opsonization

Answer 46

binding sites for macrophages on pathogen

Question 47

complement proteins

Answer 47

form 'membrane attack complex'

Question 48

vaccination

Answer 48

introduction of antigens to build immunity

Question 49

passive immunization

Answer 49

antibodies passed from mother to fetus

Question 50

artificial passive immunization

Answer 50

inject antibodies directtly

Question 51

blood groups interaction

Answer 51

different blood groups make different antigens; ie. if type A person gets B blood, B antigen lymphocytes will attack them

Question 52

tissue rejection

Answer 52

transplanted tissues make foreign MHC proteins; targeted by immune response

Question 53

allergies

Answer 53

hypersensitive response to antigens, results in inflammation

Question 54

autoimmune diseases

Answer 54

diseases caused by immune system turning against the body

Question 55

immunodeficiency

Answer 55

lowered effectiveness of immune system

Question 56

antigenic variation

Answer 56

pathogens change in epitope expression to thwart immunological memory

Question 57

latency

Answer 57

some viruses persist without making viral particles

Question 58

HIV (human immunodeficiency virus)

Answer 58

causes AIDS; both evades and damages immune system