Immune System Flashcards
(47 cards)
1
Q
Strategies of the immune system
A
- Phagocytose invaders
2. Secrete effector molecules that combat invaders
2
Q
Innate immunity
A
–quick and nonspecific
3
Q
acquired (adaptive) immunity
A
- -develops more slowly and only after the body has experienced the initial attack
- -slow and specific
- -B-cell mediated and T-cell mediated
4
Q
Parts of innate immunity
A
- skin as a barrier
- stomach acid and digestive enzymes
- phagocytosis cells such as neutrophils and macrophages
- chemicals in the blood
5
Q
agents of inflammation
A
- -histamine
- -prostaglandins
- -lymphokines
6
Q
“First responders” in innate immune response
A
- macrophages (phagocytosis) - can engulf as many as 100 bacteria
- neutrophils (phagocytosis) - can engulf 5-20 bacteria
- monocytes - mature to become macrophages in the tissue
- eisinophils and basophils - related to neutrophils
7
Q
pus
A
–composed of dead neutrophils and macrophages that die after engulfing bacteria and dead tissue
8
Q
eosinophils and basophils
A
- -innate immune cells related to neutrophils
- -eosinophils work mainly against parasitic infections
- -basophils release many of the chemicals of the inflammation reaction
9
Q
diapedesis
A
–the method by which neutrophils and monocytes enter the tissue (from the circulation)
10
Q
key feature of acquired immune system
A
–immunological memory
11
Q
B-cell immunity
A
- -a branch of acquired immune system
- -called “humoral” or “antibody-mediated immunity”
- -cannot act against invading substances that have already made their way into cells
- -promoted by B-lymphocytes
12
Q
T-cell immunity
A
- -a branch of the acquired immune system
- -also called “cell-mediated immunity”
13
Q
B lymphocytes
A
- -differentiate and mature in the adult bone marrow and the fetal liver
- -promote antibody mediated immunity
- -Each B-lymphocyte makes a single type of antibody
- -Displays an antibody on its membrane and the antibody is called a B-cell receptor
14
Q
immunoglobulin
A
antibody
15
Q
antigen
A
the foreign particle
16
Q
antigen-antibody recognition
A
–the process by which an antibody recognizes a foreign particle
17
Q
primary response
A
- -the immune response that results from the first exposure to an antigen
- -BCR recognizes the appropriate antigen
- -B-lymphocyte, assisted by a helper T-cell, differentiates into plasma cells and memory B-cells
- -memory B-cells proliferate and remain in the body
- -plasma cells and memory b-cells can be called upon to synthesize antibodies in the case of re-infection - secondary response
- -primary response requires about 20 days to reach its full potential
18
Q
plasma cells
A
- -can survive for decades or even a lifetime
- -after they are differentiated from B-lymphocyte, begin synthesizing free antibodies and releasing them into the blood
19
Q
secondary response
A
- -when plasma cells and memory B-cells are activated to make antibodies in the case of a re-infection
- -requires about 5 days to reach its full potential
20
Q
Antibody functions
A
- Mark the antigen for phagocytosis by macrophages and natural killer cells
- Bind and then begin a cascade of reactions involving blood proteins that cause the antigen-bearing cell to be perforated
- Cause antigenic substances to agglutinate, precipitate, or even may block a toxin’s chemically active portion
- Free antibodies may attach their bases to mast cells. When an antibody bound to a mast cell also binds to an antigen, the mast cell releases histamine and other chemicals.
21
Q
T-cell immunity
A
- -cell mediated immunity
- -effective against cells that have already been infected b/c it is not restricted to free-floating substances the way antibody-mediated immunity is
- -T-lymphocytes have an antibody-like protein (T-cell receptor) at its surface that recognizes antigens
- -T-lymphocytes never make free antibodies
22
Q
T-cell response
A
- -TCR recognizes the appropriate antigen
- -T-lymphocytes differentiate into helper T-cells, memory T-cells, suppressor T-cells, and killer T-cells (cytotoxic T-cells)
- -helper T-cells assist in activating B-lymphocytes
- -helper T-cells activate activate other types of T-lymphocytes including killer and suppressor T-cells
23
Q
suppressor T-cells
A
–play a negative feedback and regulatory role in the immune system
24
Q
Killer T-cells
A
- -bind to the antigen-carrying cell and release perforin, a protein that punctures the antigen-carrying cell
- -Can attack many cells b/c they do not phagocytize their victims
- -Do not themselves die when they kill invading pathogens like macrophages and neutrophils
- -responsible for fighting some forms of cancer and for attacking transplanted tissue
25
Major Histocompatibility Complex
- -MHC molecules are displayed on the surface of all cells except those that do not contain nuclei
- -Function to display antigens for recognition
26
MHC 1
- -display antigens derived from intracellular pathogens such as viruses and some bacteria
- -Since all cells can be infected by these pathogens, all nucleated cells have MHC class 1 molecules
27
MHC 2
- -display antigens derived from extracellular pathogens
| - -These pathogens must be phagocytksed, so MHC class 1 molecules are displayed by phagocytic cells
28
Professional Antigen Presenting cells (APCs)
- -cells that phagocytose extracellular bacteria or other pathogens in order to display their antigens
- -macrophages, dendritic cells, some B-cells
29
exogenous pathway
--the process by which these antigens are processed and displayed by MHC class 2 molecules on the cell surface
30
How are B-cells and T-cells activated?
- -Need two signals: Signal 1 and Signal 2
| - -After BOTH signals have been received, B-cells and T-cells are activated
31
Signal 1
--when the BCR or TCR recognizes its appropriate antigen
32
Signal 2
- -B-cells and T-cells receive it when there is an active infection
- -called the "danger signal"
33
How do T cells receive signal 1?
- -professional APCs engulf a pathogen, process antigens via the exogenous pathway, and display antigenic determinants on the MHC class 2 molecules on their surfaces
- -T-cell recognizes the combination of MHC and antigen, which provides Signal 1 via TCR stimulation and downstream signaling
34
How do T cells receive signal 2?
--provided by components of the innate immune system in response to infectious insults by circulating cytokines or up-regulation of membrane-bound surface proteins
35
How do B cells receive signal 1?
--when a free floating antigen cross-links multiple BCRs on the same cell
36
How do B cells receive signal 2?
--provided by helper T-cells
37
clonal selection
--the process by which B-cells and T-cells are selected for. That is, B-cells and T-cells that do not appropriately recognize a foreign antigen undergo apoptosis (positive selection) and those that inappropriately attack self-tissue also undergo apoptosis (negative selection)
38
Site of T-cell clonal selection
thymus
39
Site of B-cell clonal selection
bone marrow
40
How many antibodies exist for a single antigen?
ONE
41
How many antibody types does a single B-lymphocyte produce?
ONE
42
Blood type A
- -displays A antigens on cell surface
- -makes antibodies against B antigens
- -Accepts blood type A and blood type O
43
Blood type B
- -displays B antigens on cell surface
- -makes antibodies against type A antigens
- -accepts blood type B and blood type O
44
Blood type O
- -does not display any antigens on cell surface
- -Makes antibodies against type A and type B
- -accepts only blood type O
45
Rh factor
- -Rh factors are a surface protein on red blood cells
- -Rh-negative means you do not have the marker
- -Rh-positive means you do
46
Rh factor and pregnancy
- -If the mother is Rh-negative and she has an Rh-positive baby, it is not typically a problem for the fetus during the first pregnancy
- -During birth of the first child, however, the mother is exposed to the baby's blood and the mother then makes antibodies against Rh-positive blood
- -If the mother gets pregnant with another Rh-positive baby, her immune system can attack it and kill the baby
47
megakaryocyte
- -made in bone marrow
| - -giant cells that split up into platelets and are responsible for clotting function
