Chapter 21 Immune System Flashcards
1
Q
what is the definition of pathogens?
A
any disease-causing organism
2
Q
what are the names of the two “arms” of the immune system that work together to protect the body?
A
innate immune system
adaptive immune system
3
Q
in short terms, what is the innate immune system?
A
the immune system we are born with
4
Q
in short terms, what is the adaptive immune system?
A
the immune system we acquire as we encounter pathogens
5
Q
what is another name of innate immunity that helps describe some of its characteristics?
A
“non-specific immunity”
- all pathogens are treated the same way
- no recognition (memory) of specific or past infections
6
Q
what are the pros of innate immunity?
A
it is always present and working to destroy most of our pathogens
7
Q
what are the four categories of tools of innate immunity?
A
barriers
cells
antimicrobial proteins
fever
8
Q
what specific barriers do the innate immunity system use?
A
skin
mucous membranes
9
Q
what specific cells do the innate immunity system use?
A
phagocytes (such as neutrophils, macrophages, eosinophils, basophils)
Mast cells
natural killer cells
10
Q
what is another name for adaptive immunity that helps identify its characteristics?
A
“specific immunity”
has the ability to recognize and remember specific pathogens
11
Q
what are the pros of adaptive immunity?
A
has molecular recognition
has memory
is most powerful of the two
12
Q
what are the cons of adaptive immunity?
A
takes a few days to fully activate
only initiates after failure of innate immunity
13
Q
which types of organisms have innate/adaptive immunity?
A
all organisms have some innate immunity
only vertebrates have adaptive immunity
14
Q
what are the two category of tools used by adaptive immunity?
A
cells
proteins
15
Q
what specifically falls within the cells used by adaptive immunity?
A
B cells
T cells
16
Q
what specifically falls within the proteins used by adaptive immunity?
A
antibodies
17
Q
what is the first line of defense in immunity?
A
skin
mucous membranes
normal microbiota
18
Q
what is the second line of defense in immunity?
A
natural killer cells
phagocytic white blood cells
inflammation
fever
antimicrobial proteins
19
Q
what is the third line of defense in immunity?
A
T cells
B cells
antibodies
20
Q
We said the adaptive immune system has “specific
molecular recognition”, how do you think a cell can
recognize that a pathogen does not belong?
A
Molecular recognition - proteins on surface of lymphocytes bind to “non-self” proteins.
When binding occurs, the lymphocyte recognizes that it does not belong. If it quickly attempts to but immediately releases, that means that it is “self” and does belong.
21
Q
describe the strategy of the innate surface defense
A
prevent microbes from entering or remaining in the body
22
Q
list the examples of surface barriers
A
skin
tears and saliva
ciliary escalator
gastric juices
urine
microbiome
23
Q
what is the layer of skin that sheds keratin?
A
Stratum corneum
24
Q
why do we shed our outermost layer of skin?
A
keeps microbes from colonizing
25
what is the function of dermcidin? where is it found?
antimicrobial peptide produced by our sweat glands
26
how does our sweat protect us from microbes?
low pH
lysozyme
dermcidin
27
how do our tears and saliva protect us?
constantly rinse out eyes and mouth
contain lysozyme
28
what does lysozyme do?
break down bacterial cell walls
29
describe the function of the ciliary escalator? What type of tissue?
mucus membranes of respiratory tract trap microbes within the pseudostratified epithelial tissue and push them out
30
what two things does the ciliary escalator contain that aids in microbial control?
lysozyme
defensins (antimicrobial peptide excreted by epithelial cells)
31
how do gastric juices function to protect us?
is apart of the "acid mantel"
maintains acidic conditions and enzymes that break down proteins
32
what are the organs that are considered the acid mantel?
skin
vagina
stomach
33
how does urine function to protect us?
flow sweeps away microbes for excretion
34
how does our microbiome function to protect us?
help out-compete harmful bacteria
(ex: microbiome lines the inside of the stomach in order to outcompete harmful pathogens for space)
35
even though our gastric juices and saliva are within our bodies, why is it still considered apart of the surface barriers?
surface barriers consist of anything that is not on a cellular level
36
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39
what is the strategy of the innate internal defense?
neutralize any microbes that get past the first line of defense
40
what are the examples of cells responsible for innate internal defense?
neutrophils
macrophages (monocytes)
eosinophils
basophils
mast cells
natural killer cells
41
what are natural killer cells?
large granular lymphocytes capable of killing "self" cancer cells and virus-infected "self" cells
42
how do natural killer cells cause cell death?
induces target cell to undergo apoptosis (programmed cell death)
43
what are the two important phagocytic cells?
neutrophils (marines)
macrophages (close second)
44
which cell attacks pathogens first?
neutrophils
45
how exactly do neutrophils cause cell death?
respiratory burst - uses the toxic containing granules of neutrophil to kill bacteria before eating it
46
what toxins do neutrophils have in their granules?
proteases
defensins (antimicrobial peptide)
chemicals that cause hydroxyl radicals
47
how do macrophages come to be?
1. start off as inactive monocytes
2. migrate to infected tissues
3. differentiate into macrophages
48
after the neutrophils and macrophages come to ingest pathogens, how does the adaptive immune response know to begin?
macrophage sends signals to activate the adaptive immune response
49
what role do eosinophils have in the innate immune defense?
attack large parasites by releasing antimicrobial peptides and signals proinflammatory signaling (histamines)
50
what are the functions of the granules found within basophils and mast cells? name examples for each of the types
their granules contain molecules that:
1. initiate inflammation (histamine, prostaglandins)
2. attract other immune cells (Interleukin-8)
3. have anticoagulant factors (heparin)
51
what is the difference between a mast cell and basophils?
basophils freely circulate in blood
mast cells are stationary in tissue
52
what makes natural killer cells different than T cells?
they don't require MHC in order to target cell for destruction *they're a born killer*
53
what are the two proteins released by natural killer cells that cause cell death?
release 2 proteins:
1. perforin
2. granzymes
54
what is the function of perforin? what releases it?
natural killer cell
punches holes in the target cell membrane
55
what is the function of granzymes? what releases it?
natural killer cells
induce the cell to undergo apoptosis (programmed cell death)
56
57
what is a complement in terms of immunity?
group of plasma proteins, which, when activated, enhance inflammatory and immune responses
(similar to a catalyst in chemistry)
58
where are complement proteins synthesized?
liver
59
what are the three ways to activate complement?
classical pathway
lectin pathway
alternative pathway
60
where are complement when not active?
in the blood in latent state
61
what does the classical pathway of complement consist of?
uses antibodies to "turn on" compliment cascade
62
what does the lectin pathway of complement consist of?
lectin proteins (made in the liver) bond mannose sugars in bacterial cell wall, thereby activating complement proteins
63
when does the alternative pathway of complement occur?
if antibodies and lectin are not present, compliment will spontaneously activate in the absence of inhibitory proteins found on human cells
64
in very broad terms, what are the steps of the compliment activation cascade?
domino effect
1. large fragments (b) attach to surface of foreign cell (targeting for desctruction)
2. small fragments (a) float away and act as signaling molecules
65
what do the small fragments of the complement activation cascade release?
signals that:
1. stimulate histamine release
2. increase BV permeability
3. attract phagocytes
66
what are the two ways complement activation leads to target cell death?
membrane attack complex
opsonization
67
how does membrane attack complex work? what is responsible for this?
makes BIG hole in bacterial plasma membrane (causing lysis)
proteins C5b-9 of complement
68
how does opsonization work? what is responsible for this?
help phagocytes grab hold of a cell
C3b presents foreign microbe to phagocyte for destruction
C3b of complement
69
70
what is C-reactive protein's main job?
assists complement in opsonization
71
which protein is used as a blood-test marker for acute inflammation, and why?
C-reactive protein
we use this as a marker for inflammation because the liver produces an increased number (50,000x) as an inflammation response
72
what is interferon *alpha* and *beta*?
are proteins excreted by virus-infected cell which contains the message that there is a virus nearby. The nearby noninfected cell pick up these proteins/messages and then make antiviral proteins to inhibit incoming attack of the viral cell
also activates natural killer cells
73
what are the four classic signs of inflammation?
redness
swelling
heat (hot to touch)
pain
74
what is the function of inflammation?
to prep area for repair
dispose of cell debris and pathogens
activate adaptive immune system
prevents spread of infection to nearby tissues
75
when tissue damage occurs, what are all the signals produced to enact immune system?
vasodilation (to increase blood flow)
increased capillary permeability (to allow for WBCs to pass through)
Leukocytosis (WBC proliferation)
phagocyte mobilization
76
what are the hormones secreted to enact vasodilation?
nitric oxide
prostaglandins
77
what are the hormones secreted to enact capillary permeability?
histamine
heparin
78
what is the exact purpose of increasing capillary permeability?
wash foreign material into
79
does the complement cascade occur in our innate or adaptive immune system?
innate
80
what is the hormone responsible for activating leukocytosis?
prostaglandins
81
what is the process of margination? what initiates it?
initiated in response to mast cells;
Interleukin 8 "catches and attracts" WBCs at the blood vessel near the site of infection, forcing the WBCs to cling to capillary wall
82
what is the process of diapedesis?
WBCs are then able to squeeze through intercellular clefts to leave capillary
83
what is the process of positive chemotaxis?
cytokines cause WBCs to follow site of pathogen/infection instead of just wandering aimlessly
84
which is the first cell to enter the process of margination, diapedesis, and positive chemotaxis? 2nd?
neutrophils
then macrophages
85
what is an abscess?
HARD pus-filled region
pus is composed of dead tissue, bacteria and WBC
hardness is composed of collagen fibers walling off the area
86
what causes an abscess?
prolonged infection
inflammation was not enough to clear infection (instead becomes trapped inflammation)
87
at what point does a fever become unsafe?
if higher than 103 F in adults
88
why does infection cause a fever?
causes liver and spleen to accumulate iron and zinc
increases metabolic rate of tissues
89
what is the chemical signal produced to cause fever? where does it get sent to?
pyrogens (fever-causing)
signals hypothalamus
90
what are two examples of pyrogens? where are they produced?
interleukin 1 (mast cells)
lipopolysaccharide (LPS of bacteria)
91
neutrophils are not proteins
92
93
94
what are the structures of antigens?
antigen itself (body of the protein)
epitopes
95
what are epitopes?
regions located on antigens that act as the attachment site
96
what would we be talking about when referring to "immune proteins"?
antibodies
97
how many epitopes can one type of antigen recognize?
only one
98
how many various epitopes can an antigen have?
many different *key holes* (epitopes)
99
100
how does an antibody know what shape attachment it is going to have?
randomly determined by B cell
most antibodies never attach to anything, they just float around waiting for their perfect matched epitope of an antigen
101
what is the strategy of adaptive immunity?
recognize and remember specific pathogens
102
what are the tools used by adaptive immunity
B cells
T cells
103
what is the function of B cells? what type of response are they important for?
produce antibodies
humoral response
104
what is the function of T cells? what type of response are they important for?
attack abnormal human cells
secrete signaling molecules
cellular immune response
105
where do B cells maturate?
in bone marrow
106
what are the two types of cells B cells can differentiate into?
Plasma cell
memory cell
107
what is the function of plasma cells?
once its antibody has found its match, B cells differentiate into plasma cells which sole job is to make more of those specific antibodies
108
what is the function of memory cells?
B cells that had their antibody attach, can differentiate into memory cells, which sole job is to remain latent, but keeps the memory of its activated antibody in order to activate for the next same infection
109
where do T cells mature?
in the thymus
110
what is the function of T cells?
produce the T cell receptor (TCR)
Allows cell to differentiate self from non-self
binds to antigen only when presented first by MHC molecules
111
why do T cell require MHC molecules to present the antigen? what else do they require to insure this doesn't happen?
as a cautionary step to insure the T cell doesn't accidentally bind to normal cells
also receives the "go-ahead" from helper T cells
112
what are the two classes of T cells? and their old terms?
113
what is the function of Cytotoxic T cells?
destroy abnormal human cells either infected with intracellular pathogen or cancerous cells
114
How does the cytotoxic T cells use the TCR?
uses TCR to bind with antigen that is being presented by an MHC molecule of an infected human cell
115
how does cytotoxic T cell cause cell death?
kill using perforin and granzymes (similar to natural killer)
116
what is CAR T cell therapy?
the medical practice of taking your T cells and giving them a protein that can recognize cancer cells to target for destruction
117
what is the job of helper T cells?
*signaling cell*
release hormones called cytokines when their TCR binds to antigen on MHC
118
what other cells require activation by use of helper T cells?
B cells
cytotoxic T cells
119
what are antigen presenting cells function?
present antigens from microbes to other immune cells by first phagocytizing microbes
120
what are three APCs?
dendritic cells
macrophages
B cells
121
what are dendritic cells?
encounter antigen at site of infection
migrate to lymph nodes to then present antigen to T cells
122
what is the process of clonal expansion important for?
when antigen is bound to TCR of T cells or antibody of B cells, proliferation of both cells occur in order to have an abundance to help fight the infection
123
what types of cells does clonal expansion produce?
effector cells (most cells actively participating in attack)
memory cells (remain latent for now)
124
what does humoral immunity act through and their target?
acts through: antibodies circulating in fluid
targets: extracellular pathogens
125
what does the cell-mediated immunity act through and their target?
acts through: cell-to-pathogen contact (phagocytosis or cytotoxicity)
targets: intracellular viruses
126
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128
129
130
what are the five classes of immunoglobulins?
IgA
IgD
IgE
IgG
IgM
131
what are immunoglobulins another name for?
antibodies
132
what are the two broken down structures of antibodies called?
variable region (top V-shaped portion)
constant region (stem portion)
133
why is the variable region called such?
because its amino acid sequence is different in order to be able to be recognized different epitopes
134
why is the constant region called such?
determines which of the 5 classes it belongs to because each stem class remains constant
135
where are IgA found?
in body secretions
136
what is the structure of IgA?
is a dimer (two molecules linked together)
the two molecules are linked together by joint chain
137
what is the function of IgA?
prevents pathogens from entering body
138
where are IgD found?
surface of maturing B cells
139
what is the structure of IgD?
it is a monomer
140
what is the function of IgD?
first bind to antigen upon B cell activation
141
what is the location of IgE?
surface of mast cells
142
what is the structure of IgE?
monomer
143
what is the function of IgE?
trigger histamine release
is most responsible for allergies
144
what is the location of IgG?
plasma
145
what is the structure of IgG?
monomer
146
what is the function of IgG?
targets compliment and NK cells
neutralizes pathogens
agglutination
147
what is the location of IgM?
plasma (secreted first by newly activated B cells)
148
what is the structure of IgM?
pentamer (can bond at 10 sites)
149
what is the function of IgM?
1st secreted antibody
agglutination
activates complement
150
which immunoglobulin is the only one able to cross the placenta?
IgG
151
which immunoglobulin is the most abundant?
IgG
152
what is the purpose of opsonization? what helps with it?
to enhance phagocytosis
antibodies and C3b are able to attach to pathogen to make it easier to be phagocytized
153
what is the definition of agglutination?
cells clumping (can visually see)
154
what is the definition of precipitation?
protein crashing out of solution (can't see with naked eye, but may give a general cloudy appearance- precipitate in chem)
155
what are the two antibodies that can bind to antigen and begin compliment cascade?
IgG
IgM
156
How do antibodies physically help with neutralization of a pathogen?
antibody physically blocks toxin or virus from attaching to cell
(works best on small antigens)
157
what is antibody-dependent cellular cytotoxicity?
natural killer cells and eosinophils will kill cells labeled with antibody
158
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