Immune System Flashcards
1
Q
Define innate defenses
A
help prevent diseases
they are available since birth
reduce the likelihood of acquiring diseases
2
Q
How does skin protect the body
A
Has high levels of keratin that makes it resistant to acids, bases, enzymes, and toxins
3
Q
How does nasal hairs protect the body
A
filter and trap microbes
4
Q
How does cilia protect the body
A
move dirty mucus away from the air passages and nasal cavity
5
Q
How does gastric juice protect the body
A
acidic pH of stomach with enzymes to destroy bacteria
6
Q
How does lacrimal secretions protect the body
A
cleanse eyes and oral cavity ( contain lysozyme) . these are tears and saliva
7
Q
How does urine protect the body
A
acidic pH inhibit bacterial growth
8
Q
Where is acid ( acid mantle) located and its effect
A
Location: skin, vagina, mucus, urinary tract
Effect: inhibits bacterial growth
9
Q
Where is lysozyme located and its effect
A
Location: salvia, respiratory mucus, lacrimal fluids or eye
Effects: destroys bacteria
10
Q
Where are pepsin located and its effect
A
Location: stomach enzyme
Effect: destroys bacteria
11
Q
Where is mucin located and what is its effect
A
Location: mucus membrane
Effect: thick and sticky( able to trap microorganisms)
12
Q
Where is defensins located and what are there effects
A
Location: mucus membranes and skin
Effects: antimicrobial properties and control microbial colonization
13
Q
Where is “ lipids in sebum and dermcidin” located and what are there effects?
A
Location: sweat
Effect: toxic to bacteria
14
Q
What happens when surface barriers are breached?
A
an inflammatory response triggers second line of defense. Special receptors recognize foreign invaders. These special receptors are on the surface of macrophages and dendritic cells
15
Q
What are the 5 cardinal signs of inflammation
A
1) redness
2) heat
3) swelling
4) pain
5) loss of function
16
Q
When do granulocytes become phagocytic
A
When confronted with pathogens. ex are neutrophils, macrophages, dendrite cells, mast cells
17
Q
What is phagocytosis
A
phagocytes engulf pathogens into a vesicle.it only works if the pathogen adheres to the phagocyte
18
Q
What are phagocyte vesicle fused with
A
lysosome. becomes phagolysosome. the lysosome destroys the microbe
19
Q
How do some bacteria disguise themselves and how does our immune system combat that?
A
within capsules so they don’t bind to phagocytes. We coat them with antibodies ( opsonins)
20
Q
What are natural killer cells
A
cells that can kill off cancer cells or virus infected cells
part of a group called large granular lymphocytes
21
Q
What type of cell do Natural Killer cells target
A
abnormal cells. do not contain a cell surface protein called MHC. NK cells will induce them to go through apoptosis
22
Q
What release “ alarm” chemicals during inflammation
A
released by stressed tissue cells or basophilic/ mast cells
23
Q
Where do basophils circulate
A
blood
24
Q
Where are mast cells located
A
In connective tissues and mucus
25
What do Macrophages contain? How are they activated? What does it lead to?
Toll-like Receptors ( TLRs)
located on cell membrane
activated by antigens from foreign invaders
leads to a downstream immune response
26
What do inflammatory chemicals promote
vasodilation of arterioles and induce pain
27
What are Kinins? What do they promote
inflammatory chemical
induce vasodilation
helps with leukocyte movement( chemotaxis)
stimulate a pathway which leads to pain
28
What are prostaglandins? What do they stimulate?
inflammatory chemical
stimulate coagulation
initiate labor and regulation of ovulation in women
produced from membrane phospholipids
29
What 2 properties does inflammation cause
vasodilation and vascular permeability
30
What does vasodilation lead to
redness and heat
31
What does the 2 properties of inflamation allow for
allows for exudate to reach tissues
fluid with clotting factors and antibiotics
exudates leads to pain via compression of the nerve ending
pain also caused by bacterial toxins
32
What are interferons and what do they activate
proteins that are sent by cells infected by viruses to uninfected cells. They function as antivirals
They activate nk cells and macrophages ( secreted from lymphocytes)
33
What are complement proteins/plasma proteins and what do they activate
proteins that "complement" both innate and adaptive defenses. are produced in liver cells. lyse and kill certain bacteria
activated by release inflammatory chemicals
actives inflammatory events
34
When are complement proteins inactive
in blood until stimulated
35
T or F: Complement activation is explosive
True. activation increases more activation. for this reason is has to be tightly regulated because it can damage the host tissue
36
What are the 3 ways that complement proteins can protect against infection
1) Opsonization of pathogens: bind to surface of pathogens. Opsonization allows them to be swallowed by phagocytes
2) fragments of complements proteins recruit and activate more macrophages and neutrophil
3) lyse certain kinds of bacteria by drilling holes into their membranes
37
What is a fever
leukocytes and macrophages release pyrogens. Act on hypothalamus nerves and causes body temp to rise
38
Define adaptive immune system
defense system that is specific for targeting almost any type of pathogen. It is specific and systemic ( not restricted to infection site).
Contains "memory" recognize redundant pathogens
39
Define humoral immunity
antibodies available in the fluids ( humors) of the body
| B cells
40
Define cellular immunity
protection by living cells to attack living cells
direct attack or indirect attacks ( release chemicals for inflammation or activation cells)
T cells
41
Compare and contrast protein antigens to carbohydrate antigens
protein antigens more complex
carbohydrate antigens located in bacterial cell walls and red blood cells
protein antigens found on viruses and worm parasites
42
What are are MHC proteins
Major histocompatibility complex
Cell surface proteins
Identifies the cell as self and receive foreign antigens
43
What are MHC 1 proteins? What are there functions
On the surface of all tissues cells ( except RBC)
Function: display what is going on in body cells
Produced in cells and move to the cell surface
44
What are MHC 1 tagged with
Fragments of inner cell peptides called endogenous
45
Define MHC 2 and what is its function
Found on antigrn presenting cells
Base produced inside peptides for tagging by exogenous
Antigens are the engulfed and tagged… will move to cell surface
46
What are antigen-presenting cells ( 3 different type of cells)
Phagocytic meaning dendrites, macrophages, b cells
47
What do APC do to acitive b and t cells
Engulf antigens to activate the specific immune responses of B and T cells
48
What do macrophages stimulate
Stimulate t cells to release cytokines.
| Cytokines strengthen phagocytosis
49
What are the role of dendritic cells in resource to APC
Bring antigens to lymph nodes where t cells are located to carr immune response to the infected site
50
What so B cells in reference to APC
Stimulate antibody secretion
51
What is primary immune response in humoral immunity and what 2 cells do they release
Antigens bind to b cells causing b cells to divide
New cells differentiate into either plasma cells ( which secrete 2000 molecules of antibodies)
Or long lived memory cells
52
What is secondary immune response in humoral immunity
Memory cells recongnize “returning” antigens
| Antibody production is significantly more rapid than a repsonse from new antigens
53
What is active humoral immunity and the 2 ways we acquire it
When the body produce antibodies against antigens
1) naturally acquired ( response from infections)
2) artificially acquired ( receive a vaccine)
54
What is passive humoral immunity and what are the two ways we acquire it
Antibodies are introduced into body
1) naturally ( antibodies passed to fetus)
2) artifically ( antibodies from immune donor)
55
What are the basic antibody structure
Contains 4 looping polypeptides chains called antibody monomers
Symmetrical ( containing either a T or Y shape)
Has 2 heavy chains and 2 light chains
Both chains have a variable (v) regions and constant (c) regions
56
What is the antigen binding site
V region
57
What type of class is IgM? What does it secrete and what does it activate
Pentamer
Secrete first by plasma cells
Activates complement (opsonization)
58
What class is IgA. Where is it found and what is its function
Dimer
Found in body secretions
Stops pathogens from binding to epithelial surface
59
What class of antibody is IgD? Wher is it found and what is its function
Monomer
On b cells
Signals for b cell activation
60
What class of antibody is IgG? What is its function?
Monomer
Most abundent antibody
Majority of antibody based immunity
61
What class of antibody is IgE? What is its function
Monomer
| Binds allergens and triggers basophils or mast cells to release histamine for inflammation or allergenic reaction
62
What does PLAN represent in antigen/ antibody complex
P: precipitation
L: lysis
A:aggulutination
N: neutralization
63
Define precipitation
Antibodies form soluble mesh to trap antigens
64
Define lysis
Complement activation meaning bacteria to lyse
65
Define aggulutination
Free antigens of antigens on cells are clumped by network of antibodies
66
Define neutralization
Antibodies bind around bacteria or virus tovstop its function
67
What type of receptors do T cells contain
T cells receptors thst bind and recognize antigens
68
What properties do t cells contain in relationship to what regions they have on antibodies
Variable and constant regions
69
How many receptors do each t cells produce
Produces only one kind of receptor. So each t cell is specific to each kind of antigen
70
What 2 types of cells do immature t cells differentiate into
Cd4 and cd8
71
Define cd4 cells
Helper t cells ( bind to mhc 2) or regulatory t cells
72
Define cd8
Cytotoxic t cells ( bind to mhc 1) or memory t cells
73
What percentage of immature t cell will die
98% will die
74
What does t cell maturation determine
What type they will become and if they function properly
75
What is the first step of t cell maturation
Starts with immature t cells in the thymus ( thymocyte)
76
What receptors do thymocytes start with
Start with all 3 ( tcr, cd4,cd8) but not all 3 receptors will work properly
77
What is the process of figuring out what the thymocyte will differentiate into
Process of elimation
78
What are the 3 stages of t cell maturation
Beta selection
Positive selection
Negative selection
79
What is being determined in the beta selection
do t cells have proper t cell receptors ( TCR)
80
Where are TCRs located and what percentage of thymocytes contain them
Located on the surface of t cells
| 5 %
81
What happens durring beta selection if the cells does not have proper TCRs
die by apoptosis
82
What is the role of t cell recpetors ( TCRs)
accept self antigens from the antigen presenting cells. Fundamental for T cells to accept and be activated by antigens
83
What is being determined in positive selection step
thymocytes with TRCs are tested for whether they can bind to MHC or 1 or II proteins with antigens. It weeds out the ones that are too weak/unresponsive
84
How does the cells pass the postive selection step
if they can at least bind to the MHC weakly they pass
| cannot bind= apoptosis
85
What is detected in the negative selection
detecting wheater some thymocytes are too strongly reactive
86
How is negative selection tested
with self antigens.
87
What is being determined during the negative selection
weeding out the ones that could cause autoimmune disease
88
What 2 cells are used in cellular immunity
CD4+ and CD8+
89
cd4+ signals for help by....
MHC II proteins
| when MHC II are loaded with foreign antigens
90
CD8+ cells activated by.....
MHC I proteins
| also tag cell as healthy or abnormal by the antigens binding to MHC I proteins
91
How are T cells activated
activated by APCs
92
Define antigen binding
T cells bind to APCs and receive the antigen
93
define co-stimulation
activation of the T cell by the interaction with APC.This step must occur to activate a T cells
94
What is the 4 role of Helper T cells
1) Help activate b/t cells
2) binds to b cells and this causes t helper to release cytokines causing b cells divide rapidly
3) help activate CD8 that then activate cytotoxic t cells
4) release cytokines and this attracts WBCs to area, mobilize lymphocytes and macrophages
95
What is the role of cytotoxic t cells
can directly attack and kill other cells.
| It looks for foreign or abnormal antigens on cells
96
How are cytotoxic cells different from natural killer cells
cytotoxic t cells look for foreign or abnormal antigens on cells
NK cells look for absent/ incomplete MHC I proteins
97
What 2 forms of attacks due cytotoxic cells use
Perforins and Granzymes
98
What are perforins
glycoproteins that drills into target cell membrane
99
What are granzymes
proteases that induce apoptosis in target cells/virus/etc
100
What are the 3 roles of regulatory cells
dampen the immune responses
act through divert contact or inhibit cytokines
prevent autoimmune reactions
101
How are regulatory cells produced
produced from some thymocytes that passed the maturation process
102
Why does immune tolerance occur
to not launch attacks against reoccurring exposures. to prevent matural immune attacks on fetus in the womb
103
In what way does grafting uses immune tolerance
patients are exposed ti doses of the donor antigens before the procedure to reduce reaction`
104
Define antigens
generally foreign molecules that triggers an immune response in the body
105
What are antigenic determinants
epitopes
the specific part of the molecules that trigger an immune response
antigens can contain many antigenic determinants
106
Can multiple T cells bind to the antigens due to having many epitopes
yes
