Ch.14 Innate Immunity Flashcards
(164 cards)
1
Q
What are first line defenses?
prevent entry
A
- skin and mucus membranes
- antimicrobial substances
2
Q
What are sensor systems?
detect invaders
A
- pattern recognition receptors (PRRs)
- complement system
detect damage and microbial invasion
3
Q
What are innate effector actions?
eliminate threat/ invader
A
- interferon response
- phagocytosis
- complement activation
- inflammatory response
- fever
4
Q
What is dermis?
A
tightly woven fibrous connective tissue
5
Q
What is epidermis?
A
many layers of epithelial cells
* outermost are dead and filled with keratin
* repels water
* continually flake off
* epidermal dendritic cells phagocytize pathogens
6
Q
True or False
Salt inhibits growth of pathogens
A
True
7
Q
True or False
Antimicrobial peptides (defensins) form pores in microbial membranes
A
true
8
Q
True or False
Lysozyme destroys cell wall of bacteria
A
True
9
Q
True or False
Sebum secreted by sebaceous oil glands help keep skin pliable and lowers skin pH
A
True
10
Q
Where are mucous membranes in the body?
A
respiratory, digestice, urinary, and reproductive tracts
11
Q
True or False
Goblet and ciliated columnar cells help remove invaders
A
True
12
Q
True or False
Epithelial cells are living and single layered
A
True
13
Q
True or False
Peristalsis of intestines remove microbes
A
True
14
Q
where are lysozymes found?
A
tears, saliva, mucus
15
Q
Where are antimicrobial peptides present?
A
mucus
16
Q
Where are peroxidases present?
A
- saliva
- breast milk
- tissue fluids
17
Q
Where is lactoferrin present?
A
saliva, mucus, breast milk, and some phagocytes. This is an iron binding protein
18
Q
What is microbial antagonism?
A
members of the microbiome make it hard for pathogens to compete
* consumption of nutrients
* create unfavorable environments to other microbes
* prevent pathogens from attaching to host cells
* provide vitamins to host
19
Q
What is the function of first-line defenses?
A
prevent microbial entry
20
Q
What is the function of sensor systems?
A
detect damage and microbial invasion
21
Q
What is the function of innate effector actions?
A
eliminate invader
22
Q
Is the skin easy or difficult for microbes to penetrate?
A
difficult
23
Q
what are the outermost epithelial cells of the epidermis characterized by?
A
dead and filled with keratin with repels water and maintains a dry environment
24
Q
what part of the epidermis phagocytize pathogens?
A
epidermal dendritic cells
25
what role does skin play in innate immunity?
skin has chemicals that defend against pathogens
26
what chemicals does the skin use to defend against pathogens?
- salt
- antimicrobial peptides
- lysozymes
27
role of salt as an antimicrobial substance
inhibits growth of pathogens
28
role of antimicrobial peptides (defensins) as antimicrobial substance
forms pores in microbial membranes
29
role of lysozyme as antimicrobial substance
destroys cell wall of bacteria
30
What do mucous membranes line?
body cavities open to the environment
31
what do goblet cells and ciliated columnar cells in the epidermis do?
help remove invaders
32
peroxidases
part of systems that form antimicrobial compounds
33
what methods does microbial antagonism use to make it difficult for pathogens to compete?
- consumption of nutrients
- create environment unfavorable to other microbes
- prevent pathogens from attaching to host cells
- help stimulate the body's second line of defense
- generate antimicrobial compounds
- promote overall health by providing vitamins to host
34
disruption of microbiome with antibiotics leads to what?
infections
35
when does the body's second line of defense operate?
when pathogens penetrate the skin or mucous membranes
36
what is the body's second line of defense composed of?
- cells
- antimicrobial chemicals
- processes
37
many of the components of the second line of defense are contained in or originate in ________
blood
38
neutrophils consist of what percentage of circulating WBCs?
50%
39
types of granulocytes
- neutrophils
- basophils
- eosinophils
40
what is the first granulocyte recruited?
neutrophils
41
what do basophils cause?
release of histamine which causes an allergic response
42
which granulocyte is released to fight ectoparasites?
basophils
43
what are eosinophils used for?
parasite defense and allergic response
44
what do eosinophils release? what does this do?
histamines, which breaks down histamine
45
what do granulocytes contain?
granules with active chemicals
46
how do neutrophils kill bacteria?
phagocytosis
47
what do the granules of basophils contain and what do they do?
histamine and other chemicals that increase capillary permeability during inflammation
48
what are basophils involved in?
allergic reactions and inflammation
49
what do granules of eosinophils contain?
antimicrobial substances and histaminase
50
lifespan of a neutrophil
1-2 days
51
neutrophil extracellular traps
A network of chromatin (DNA) fibers formed from dead neutrophils that binds microbes inhibiting colonization
52
when do monocytes differentiate into macrophages?
upon migration into tissue
53
where are monocytes found?
circulating blood
54
function of macrophages
sentinel; tissue specific phagocytes
55
specific types of macrophages
- microglia
- kupffer cells
56
what types of tissues contain macrophages?
almost all tissue types
57
function of dendritic cells
bring material to adaptive immune system for inspection
58
dendritic cells
specialized WBCs that act as a bridge between innate and adaptive immunity
59
function of lymphocytes
produce antibodies
60
types of lymphocytes
- T cells
- B cells
- innate lymphoid cells (natural killer cells)
61
how do innate lymphoid cells differ from T and B cells?
ILCs have a similar function to T/B cells but lack specificity of antigen recognition
62
cell communication allows _________
coordinated response
63
surface receptors
serve as the eyes and ears of the cell
64
where are surface receptors found?
span the membrane and connect outside to inside
65
what induces a response from surface receptors?
binding to specific ligand
66
cytokines
chemicals that are produced by cells, diffuse to others, and bind to appropriate receptors to induce changes
67
what changes can cytokines induce?
cytokines induce?
- growth
- differentiation
- movement
- cell death
68
function of cytokines
voices of the cell
69
do cytokines act at a low or high concentration?
low
70
adhesion molecules
allow cells to adhere to other cells
71
example of adhesion molecules
endothelial cells can adhere to phagocytic cells and allow them to exit the bloodstream
72
pattern recognition receptors
see signs of microbial invasion and lead to cytokine secretion
73
what do pattern recognition receptors (PRRs) detect?
microbe-associated molecular patterns (MAMPs)
74
what do microbe-associated molecular patterns include?
- cell wall components (peptidoglycan, lipoteichoic acid, lipopolysaccharide, lipoproteins)
- flagellin subunits
- microbial nucleic acid
75
PAMPs are ____________-associated, but not exclusive to ____________
pathogen; pathogens
76
damage-associated molecular patterns (DAMPs)
indicate cell damage
77
where are pattern recognition receptors located?
- cell surface
- in endosomes and phagosomes
- free in cytoplasm
78
what do PRRs on the cell surface detect?
microbial components present in the cell's surroundings
79
what do PRRs in phagosomes and endosomes detect?
components of microbes ingested by the cell
80
what do PRRs in the cytoplasm detect?
cell damage as well as microbial components in the cell's cytoplasm
81
T/F: phagocytes always have pattern recognition receptors
T
82
where are toll-like receptors found?
anchored in membranes of sentinel cells
83
what do surface TLRs do?
monitor extracellular environment
84
what do TLRs in phagosomal or endosomal membranes of organelles characterize?
ingested material
85
TLRs are specific for what?
distinct MAMPs
86
dendritic cells have both TLRs and _______
CLRs (C-type lectin receptors)
87
RIG-like receptors (RLRs)
detect viral RNA (often double stranded)
88
where are RIG-like receptors found?
cytoplasm
89
NOD-like receptors (NLRs)
detect microbial components of cell damage
90
where are NOD-like receptors found?
cytoplasm
91
NLRs in macrophages or dendritic cells combine with other proteins to form _________
inflammasome
92
interferon response
1. PRRs detect viral DNA; cell produces interferon (IFN)
2. IFN causes neighboring cells to express inactive antiviral proteins (iAVPs)
3. iAVPs activated by viral dsRNA
4. mRNA is degraded, protein synthesis stops, and infected cells undergo apoptosis
93
types of cytokines
- chemokines
- colony-stimulating factors
- interferons
- interleukins
- tumor necrosis factor
94
chemokine function
chemotaxis of immune cells
95
colony-stimulating factors function
multiplication and differentiation of leukocytes
96
interferons function
control of viral infections and regulation of immune responses
97
interleukins function
important in innate and adaptive immunity
98
what produces interleukins?
leukocytes
99
tumor necrosis factor function
causes inflammation and apoptosis of tumor cells
100
do cytokines act alone or in groups?
in groups or in sequence to generate a response
101
what are adhesion molecules needed for?
to leave circulation and enter tissue
102
complement system
proteins in the blood that help antibodies kill their target and complements activities of adaptive immune system
103
what proteins are involved in the complement system?
C1 through C9
104
the complement system is activated by how many different pathways?
three
105
what does the activation of the complement system lead to?
formation of C3 convertase, which splits C3
106
what are the 3 pathways of activation for the complement system?
1. alternative pathway
2. lectin pathway
3. classical pathway
107
alternative pathway of complement system
triggered when C3b binds to foreign cell surfaces (C3 is unstable, so some C3b always present)
108
lectin pathway of complement system
pattern recognition molecules (mannose-binding lectins or MBLs) bind to mannose of microbial cells and interact with complement system components
109
classical pathway of complement system
activated by antibodies bound to antigen, which interact with complement system
110
activation of the complement system produces what 3 major outcomes?
1. opsonization
2. inflammatory response
3. lysis of foreign cells
111
opsonization
coating antigen with antibody enhances phagocytosis
112
how does activation of the complement system cause opsonization?
C3b binds to bacterial cells and foreign particles, promoting engulfment by phagocytes that attach to opsonins like C3b
113
how does activation of the complement system cause inflammatory response?
C5a attracts phagocytes to area; C3a and C5a increase permeability of blood vessels, inducing mast cells to release cytokines
114
how does activation of the complement system cause lysis of feign cells?
membrane attach complexes (MACs) formed by proteins C5b, C6, C7, C8, and C9 molecules assembling in cell membranes of Gram-negatives
115
what does regulation of the complement system prevent?
prevents host cells from activating the complement system
116
how does regulation prevent host cells from activating complement system?
molecules in host cell membranes bind regulatory proteins that inactivate C3b, preventing opsonization or triggering of alternative pathway
117
phagocytosis
phagocytes engulf and digest material and pathogens
118
What cells go through phagocytosis?
neutrophils, dendritic cells, and macrophages
119
chemotaxis
phagocytes recruited by chemoattractants
120
chemoattractants
products of microorganisms, phospholipids from injured host cells, chemokine, C5a
121
steps of phagocytosis
1. chemotaxis
2. recognition and attachment
3. engulfment
4. phagosome maturation and phagolysosome formation
5. destruction and digestion
6. exocytosis
122
recognition and attachment step of phagocytosis
direct (receptors bind mannose) and indirect (binding to opsonins)
123
engulfment in phagocytosis
pseudopods surround and form phagosome
124
phagosome maturation and phagolysosome formation in phagocytosis
directed by TLRs; fuse with lysosomes containing enzymes
125
destruction and digestion in phagocytosis
toxic ROS and nitric oxide produced; pH decreases; enzyme degrade; peptides damage membrane of invader; lactoferrin binds iron
126
exocytosis in phagocytosis
vesicle fuses with cytoplasmic membrane, expels remains
127
what do macrophages do?
phagocytize dead cells and debris and destroy invaders
128
how long do macrophages live?
weeks or month
129
what do macrophages regenerate?
lysosomes
130
macrophages are always present where?
in tissues
131
what are macrophages replaced by?
monocytes
132
activated macrophages are a response to what?
cytokines
133
M1 macrophages vs M2 macrophages
- M1 macrophages have greater killing power
- M2 macrophages lessen inflammation
134
if activated macrophages are insufficient, they can fuse to form ___________
giant cells
135
granulomas
walled-off organisms or material-resistant to destruction which prevent escape but interfere with normal tissue function
136
granulomas cause what types of disease?
tuberculosis, etc.
137
what makes up granulomas?
- macrophages
- giant cells
- T cells
138
why are macrophages important sentinel cells?
they alert other immune cells
139
what causes inflammation?
infection or tissue damage
140
purpose of inflammation
contain site of damage, localize response, eliminate invader, and restore tissue function
141
what does inflammation result in?
- swelling
- redness
- heat
- pain
- sometimes loss of function
142
what causes PRRs to trigger?
detection of MAMPs and DAMPs
143
what occurs after PRRs are triggered?
host cells release inflammatory mediators (cytokines and histamine)
144
inducers of inflammation
microbes, tissue damage
145
MAMPs causes the release of what? what does this do?
tumor necrosis factor (TNF) which induces the liver to produce acute phase proteins that activate complement
146
blood vessel damage starts what? what does this lead to?
2 enzymatic cascades, leading to coagulation and increased vessel permeability
147
inflammatory process steps
1. dilation of small vessels
2. migration of leukocytes from bloodstream to tissues
3. clotting factors wall off site of infection
4. dead neutrophils and tissue debris accumulate as pus
148
why does the inflammatory process cause dilation of small blood vessels?
- greater blood flow (heat and redness); slower flow rate
- leakage of fluids (swelling, pain)
- fluids contain transferrin, complement, and antibodies
149
what occurs when leukocytes migrate from bloodstream to tissues in inflammatory process?
- endothelial cells "grab" phagocytes and slow them down
- phagocytes squeeze between cells of vessel (diapedesis)
150
purpose of clotting factors walling off site of infection in inflammatory process
prevents bleeding and stops the spread of microbes
151
inflammatory response prevents ________ but damages ___________
spread; tissues
152
which part of the inflammatory response causes damage to tissues?
enzymes and toxic compounds released from phagocytic cells
153
necrosis
traumatic cell death due to damage
154
apoptossi
programmed cell death; does not trigger inflammatory response
155
pyroptosis
PRRs in a macrophage trigger an inflammatory response that sacrifices infected cells
156
why does fever occur with infection?
- temperature-regulation center in the brain normally holds at 37ºC, but raises during infection in response to pyrogens
- growth rates of bacteria optimized for 37ºC typically drop sharply above optimum, allowing more time for defenses
- moderate temperature rise increases rates of enzymes
157
what oral temperature is considered a fever?
>37.8ºC
158
what are pyrogens made by?
the body or microbes
159
what does temperature rise do for the body during infection?
- enhances inflammatory response
- phagocytic activity
- multiplication of lymphocytes
- release of attractants for neutrophils
- production of interferons and antibodies
- release of leukocytes from bone marrow
160
How is Inflammation caused?
dilutes and leaks fluids from vascular system
161
classical pathway of complement system
activated by antigen-antibody complex
162
alternative pathway of complement system
is activated on microbial cell surfaces in the absence of antibodies and is a component of innate immunity
163
lectin pathway of complement system
activitaed by a plasma lectin that binds to mannose on microbes & activates the classical system pathway in the absence of antibody
164
what are the 3 lines of defense of the immune system?
1. skin, mucous membranes, enzymes, natural flora on the skin and in the GI tract
2. innate immunity: phagocytes, natural killer T cells, granulocytes, complement proteins, macrophages
3. acquired immunity: antibodies, B and T lymphocytes
