LECTURE 10: IMMUNSE SYSTEM Flashcards
1
Q
- lymphatic capillaries take up and return excess fluid
to the bloodstream - lacteals receive lipoproteins and transport them to
the bloodstream - helps defend body against disease
A
Lymphatic System
2
Q
lymphatic organs:
A
-red bone marrow,
-thymus gland,
-tonsils,
-spleen,
-lymph vessels (lymphatic capillaries)
-lymph nodes
2
Q
take up and return excess
fluid to the bloodstream
A
Lymphatic capillaries
3
Q
Capsule surrounding two distinct
regions, cortex and medulla
A
Lymph Nodes
4
Q
congregate in cortex when
fighting off a pathogen
A
Lymphocytes
5
Q
concentrated in medulla -
cleanse lymph
A
Macrophages
6
Q
Lymph nodes named for their __________
A
location
6
Q
- Located in upper left
region of abdominal cavity
just beneath diaphragm - Cleanses blood
- Found in all vertebrates
- Mechanical filtration of red blood cells to remove
old red blood cells - Active immune response through humoral and cell-mediated pathway
A
Spleen
7
Q
- Patches of lymphatic tissue
located around the
pharynx - First to encounter
pathogens that enter via
the nose and mouth
A
Tonsils
8
Q
- Located along trachea
behind the sternum in
upper thoracic cavity - Produces thymic hormones
A
Thymus Gland
9
Q
- Origin for all types of blood
cells - Area of maturation for most
white blood cells
A
Red Bone Marrow
10
Q
- Blind-ended tube connecting to the caecum
- Shrunken remnant of the part of the caecum
- found in the digestive tracts of many extant
herbivores - house mutualistic bacteria which help animals
digest the cellulose molecules that are found
in plants - may harbour and protect bacteria that are
beneficial in the function of the human colon
A
Appendix
11
Q
inflammation of the appendix
A
Appendicitis
12
Q
2 category of Defense Mechanism
A
-Innate immunity (Nonspecific defense mechanism)
-Adaptive Immunity (Specific defense Mechanism
13
Q
Category under Innate immunity (Nonspecific defense mechanism)
A
-First line of defense
-Second Line of defense
14
Q
Category under Adaptive Immunity (Specific defense Mechanism
A
third line of defense
15
Q
-(non-specific) is present before any exposure to pathogens and is effective from the time of birth.
-It responds to a broad range of pathogen
-Recognition of traits shared by broad ranges of pathogens, using a small set of receptors
- Rapid response
A
Innate immunity
16
Q
-(acquired/specific), develops after exposure to agents such as microbes, toxins, or other foreign substances.
-It involves a very specific response to pathogens
-Recognition of traits specific to particular pathogens, using a vast array of receptors
- Slower response
A
Adaptive immunity
17
Q
agents that cause disease, infect a wide
range of animals, including humans
A
Pathogens
18
Q
recognizes foreign bodies and
responds with the production of immune cells and proteins
A
immune system
19
Q
All animals have__________________, a
defense active immediately upon infection
A
innate immunity (non-specific)
20
Q
Components of Immune system recognition and response
A
-immunocytes (lymphocytes and
macrophages)
-plus a diverse array of molecules
(antibodies, lymphokines, etc.)
21
Q
Formed elements (45 %) – produced by bone marrow
A
BLOOD
22
Q
Multipotential stem cell —–>
A
-Myeloid stem cell
-Lymphoid stem cell
23
Myeloid stem cell--->
Macrophage Precursor---->Monocyte---> Macrophage
24
Lymphoid Stem cell ---->
-B cell precursor
-natural killer precursor
-T cell precursor
25
B cell precursor--->
B Cell----> (two possible result)---> Plasma cell/memory cell
26
Natural killer precursor--->
natural killer cell--->activated natural killer cell
27
T cell precursor--->
T cell---> (two possible result)---> helper T cells/ cytotoxic T cell
28
-innate defenses include barrier defenses, phagocytosis, antimicrobial peptides.
-Main function is to prevent infection
-Barrier defenses - skin and mucous membranes of the respiratory, urinary, and urinary tracts
-Mucus traps and allows for the removal of microbes
-Many body fluids including saliva, mucus, and tears are hostile to many microbes
-The low pH of skin and the digestive system prevents growth of many bacteria
First Line of Defense – Natural Barriers
29
Components of the 1st Line of Defense
-Saliva, sweat, tears and mucus
-Cilia
-Stomach Acid
30
* Bathe surfaces and wash away many potential invaders
* Many secretions contain antimicrobial proteins
Saliva, sweat, tears and mucus
31
❑digests cell walls of bacteria
❑destroys many microbes at eyes and upper resp.
tract
Lysozyme
32
* Traps particles
* Swallow or expel
Mucus
33
Line the cells of the trachea
(windpipe) and help sweep
out microbes trapped in
mucus there.
Cilia
34
Kills many microbes
present in food before
they reach intestines.
Stomach Acid
35
Second Line of Defense – Three Mechanisms
1. Phagocytic and Natural Killer Cells'
2. Localized Inflammatory Responses
3. Antimicrobial Peptides and Proteins
36
Phagocytic and Natural Killer Cells
a. Neutrophils
b. Monocytes
c. Eosinophils
d. natural killer cells
37
* attracted to damaged cells, enter the infected
tissue, engulfing and destroying pathogens
*self-destruct and live only for a few days
*Chemotaxis – migration towards the source of
chemical attractant
Neutrophils
38
migration towards the source of
chemical attractant
Chemotaxis
39
* transformed to macrophages once they enter the affected tissue; effective and long-lived
* Macrophages – “big-eaters; engulf microbes in a vacuole – fused with lysosomes – kill the microbe
* Mechanism:
▪ generate toxic forms of O2
▪ digestion of microbial
components (lysosomal enzymes)
Monocytes
40
“big-eaters; engulf microbes in a
vacuole – fused with lysosomes – kill the microbe
Macrophages
41
Mechanism of monocytes
▪ generate toxic forms of O2
▪ digestion of microbial
components (lysosomal enzymes)
42
* against larger parasitic
invaders (blood fluke.
Schistosoma mansoni)
* discharge destructive
enzymes targeting the parasite’s
external wall
Eosinophils
43
-circulate through the body and detect abnormal
cells
-release chemicals leading to cell death, inhibiting the spread of virally infected or cancerous cells
-does not attack microbes but destroy virus-infected or abnormal cells
-do not phagocytose but mount an attack via lysis of infected cell
natural killer cells
44
-Occurs when there is damage to tissue (physical injury) or by entry of microorganisms
-Four symptoms: redness, pain, swelling and heat
-inflammatory response, such as pain and swelling, is brought about by molecules released upon injury of infection
-Mast cells, a type of connective tissue, release
histamine, which triggers blood vessels to dilate and become more permeable
Localized Inflammatory Responses
45
Four symptoms of localized inflammatory response
redness, pain, swelling and heat
46
a type of connective tissue, release
histamine, which triggers blood vessels to dilate and
become more permeable
Mast cells
47
Localized Inflammatory Response : Activated macrophages and neutrophils release _________, signaling molecules that enhance the immune response
cytokines
48
Localized Inflammatory Response: Enhanced blood flow to the site helps deliver antimicrobial peptides that result in an accumulation of ____
pus
49
a fluid rich in white blood cells,
dead pathogens, and cell debris from damaged tissues
pus
50
damage to tissue by physical injury or entry of
microorganisms triggers a localized
inflammatory response
Second Line of Defense
51
Example of Second Line of Defense
-Fever
-Septic Shock
52
* systemic inflammatory response triggered by substances
released by macrophages in response to certain pathogens
* response to toxins BUT certain WBCs release molecules called
PYROGENS which set the body’s thermostat at a higher temp.
Fever
53
set the body’s thermostat at a higher temp
PYROGENS
54
❑inhibits growth of some microbes
❑May speed up phagocytosis and tissue repair by speeding up body chemical reactions
MODERATE fever
55
a life-threatening condition caused by an
overwhelming inflammatory response
Septic shock
56
Peptides and proteins function in innate defense by
attacking pathogens or impeding their
reproduction
Antimicrobial Peptides and Proteins
57
Antimicrobial Peptides and Proteins
a. Lysozymes
b. Interferon
c. Complement system
58
antimicrobial enzymes present in
saliva, tears, and mucous secretion
Lysozymes
59
secreted by virus-infected cells; bind
to receptors of non-infected cells and induce them to produce substances
b. Interferon
60
proteins which carry out
cascade of steps which causes lysis of invading cells
and helps trigger inflammation
Complement system
61
Second Line of Defense: some microbes have evolved mechanisms for
evading phagocytic destruction. Ex: ____
– outer capsules
– Mycobacterium tuberculosis are readily engulfed but are resistant to lysosomal destruction and can even reproduce inside a macrophage
62
key cells
of the immune system
Lymphocytes
63
two main types of
lymphocytes:
B lymphocytes (B cells) and T lymphocytes (T
cells
64
* Adaptive (specific) immunity
* Bursa of Fabricius – Chang & Glick
* a foreign molecule that elicits a specific response
by lymphocytes is called an antigen
* Antigens react to specific antibodies that are
either attached to lymphocytes or are secreted
Third Line of Defense (Adaptive Immunity)
65
response mounted by the immune
response (lymphocytes) against pathogens or antigens
Immune Response
66
recognizes and directed against
particular antigens of foreign substances
Antigen-specific
67
immunity is not restricted to initial
infection site
Systemic
68
recognizes and mount enhanced
attack on previously encountered antigens
Immune response has memory
69
T or B cells bind to antigens via ______________ specific to part of one molecule of that pathogen
antigen receptors
70
a foreign molecule that elicits a specific response by lymphocytes is called an __________
antigen
71
Antigens react to specific ___________ that are
either attached to lymphocytes or are secreted
antibodies
72
an antibody interacts with a small, accessible portion of the antigen called an ________ or antigenic determinant
epitope
73
Each B cell antigen receptor is a ___________________ with two identical ____________ and two identical ____________
-Y-shaped molecule
-heavy chains
-light chains
73
The constant regions of the chains vary little among B cells, whereas the ______________ differ greatly
variable regions
74
The variable regions provide_______________
antigen specificity
75
First step in B cell activation
Binding of B cell antigen receptor to an antigen
76
First step of B cell activation gives rise to cells
that secrete a soluble form of the protein called an ____________________________
antibody or immunoglobulin (Ig)
76
Each T cell receptor consists of two different polypeptide chains called ______________
alpha and beta
76
Antibodies have the
same Y shape as B cell
antigen receptors but are
___________, not membrane
bound
secreted
76
The tips of the chain form a ___________ region; the rest is a __________ region
-variable (V)
-constant (C)
76
T cell and B cell antigen receptors are functionally _______-
different
77
Enormous Variety of B and T cells in the body allows the immune system to respond to
millions of ___________, and thus millions of
_______________
-antigens
-potential pathogens
77
What activate lymphocyte?
binding of a mature lymphocyte to an antigen
77
although a microorganism encounters a large
repertoire of B cells and T cells, it interacts only
with ____________ bearing receptors specific for
its various antigenic molecules
lymphocytes
77
In the body there are few lymphocytes with
antigen receptors for any particular _________
epitope
77
In the ________________, an antigen is exposed to a steady stream of lymphocytes until a match is made
Lymph Node
78
Once activated, a B or T cell undergoes multiple cell divisions called?
Clonal Selection
79
Clonal Selection
produce a clone of identical cells
80
Some cells from the clone become short-lived ___________ that act immediately against the antigen
effector cells
81
responsible for long-term
protections against diseases
Immunological Memory
81
Some cells from the clone become long-lived ____________ that can give rise to effector cells if the same antigen is encountered again
memory cells
81
Effector cells are ____________ that secrete antibodies
plasma cells
82
The first exposure to a specific antigen represents the
primary immune response
83
During primary immune response, selected B and T cells give rise to their
________________
effector forms
84
In the _____________________, memory cells facilitate a faster, more efficient response
secondary immune response
84
While B cells and T cells are maturing in the
____________ and __________, their antigen
receptors are tested for potential self-reactivity
-bone marrow
-thymus
84
What is tested (potential self-reactivity) in the antigen of B and T cells?
– capacity to distinguish self from nonself continues to develop as the cells migrate to lymphatic organs
– autoimmune diseases
85
Why is it needed to check autoimmune disease in the antigen of B and T cells?
Caused when the immune system mistakes its own cells as pathogens and attack them
85
The defenses provided by B and T lymphocytes can be divided into humoral immune response and the cell-mediated immune response
Adaptive (Specific) Immunity
86
antibodies help neutralize or eliminate toxins and pathogens in the blood and lymph
Humoral immune response
86
specialized T cells destroy affected host cells
Cell-mediated immune response
86
_______ interact with one important group of
native molecules
T cells
87
collections of cell surface glycoproteins
encoded by a family of genes called the
major histocompatibility complex (MHC)
88
have class I and class II MHC molecules on their surfaces
Antigen-presenting cells
89
Two main classes of MHC molecules mark
body cells as self:
*Class I MHC molecules
*Class II MHC molecules
90
found on almost
all nucleated cells
Class I MHC molecules
90
restricted to macrophages, B cells, activated T cells, and those inside the thymus
Class II MHC molecules
90
two main types of T cells, each responds to one
class of MHC molecule
-Cytotoxic T cells (TC)
-Helper T cells (TH)
91
have antigen receptors that
bind to protein fragments displayed by the body’s class I MHC molecules
Cytotoxic T cells (TC)
92
have receptors that bind to
peptides displayed by the body’s class II MHC
molecules
Helper T cells (TH)
93
___________ cells respond by killing the infected cells
Cytotoxic T
94
_____________ send out chemical signals that incite other cell types to fight the pathogen
Helper T cells
95
How Class I MHC molecule function?
If the cell contains a replicating virus, class I
MHC molecules expose foreign proteins that
are synthesized in infected or abnormal cells to
cytotoxic T cells
95
this interaction (MHC molecule exposing foreign proteins) is greatly enhanced by a __________________ which helps keep the cells together while the TC cell is activated
T surface protein CD8
96
Binding of Antibodies to antigens inactivates antigen by:
-Neutralization
-Agglutination of antigen-bearing particles
-Precipitation of soluble antigens
-complement fixation (activation of complement)
97
Five Classes of Immunoglobulins
-IgM (Pentamer)
-IgG (monomer)
-IgA (dimer)
-IgD (monomer)
-IgE (monomer)
97
Blocks viral binding sites; coats bacteria and/or opsonization
Neutralization
97
Neutralization, Agglutination of antigen-bearing particles, and Precipitation of soluble antigens enhances?
Phagocytosis
97
Process of Complement System
1. A trigger (like an antibody-antigen complex) initiates the complement cascade by activating the first complement protein in the pathway.
2. Activated complement proteins sequentially cleave and activate the next protein in the cascade, amplifying the response.
3. C3b binds to the pathogen surface, marking it for phagocytosis by immune cells.
4. Complement fragments like C3a and C5a stimulate mast cell degranulation, leading to histamine release and increased vascular permeability.
5. In the final step of the cascade, the MAC is formed on the pathogen membrane, causing cell disruption
97
Complement fixation leads to?
Cell Lysis
98
part of your body's immune system that cleans up damaged cells, helps your body heal after an injury or an infection and destroys microscopic organisms like bacteria that make you sick
Complement System
98
* first to be produced after
initial exposure to antigen
* promotes neutralization
and cross-linking of
antigens
* very effective in
complement system
IgM (pentamer)
99
* most abundant Ig in blood
* promotes opsonization,
neutralization and cross-linking of antigens
* only Ig that crosses
placenta
* present in tissue fluids
IgG (monomer)
100
* present in tears, saliva,
mucus, and breast milk
* provides localized defense
of mucous membranes by
neutralization and cross-linking of antigen
IgA (dimer)
101
* present on surface of B
cells that have not been
exposed to antigens
* acts as antigen receptor in
the antigen-stimulated
proliferation and
differentiation of B cells
IgD (monomer)
102
* present in blood at low
concentrations
* triggers release from mast
cells and basophils of
histamine and other
chemicals that cause
allergic reactions
IgE (monomer)
103
what do you call the condition/ hemolytic disease where in a mother is Rh- and the baby is Rh+. The mother's Rh factor attacks the baby in the placenta?
Erythroblastosis fetalis
