Definitions And Questions Flashcards
(124 cards)
1
Q
What is the function of the immune system?
A
Is a diffuse collection of cells and organs that are responsible for the ability to resist infections and diseases
2
Q
What does the immune system protect the rest of the body from?
A
Pathogens, toxic material, and its own misfunctioning cells
3
Q
What system does the immune system closely intertwined with?
A
With the lymphatic system, but not completely overlapping
4
Q
The body has multiple layers of défense against infections. What are est 2 defences and describe them each.
A
Physical Barrier: Anatomical and physiological mechanisms that prevent entry of foreign organism and substances
Cell-mediated immune responses: Innate and adaptive defence responses that rely on WBC activity
-> Innate immune response: cell recruitment to injured tissue and release of pro inflammatory mediators
-> Adaptive Immune Activation: Activation and clinal expansion of lymphocytes
5
Q
Physical barriers
A
Are protective features that are created by non-immune cells
6
Q
Anatomical/Physiological (physical) barriers come in 2 major categories:
- Structural features
-> Ex: skin - describe the skin - Chemical secretion
A
Structural features: that work to prevent a pathogen from entering the body. (Ex: skin and hair)
- describe the skin: lecture #36 slide 6
Chemical secretions: that are used to neutralize and destroy them (ex: iysozyme, stomach acid)
These défenses are all creates by cells that are not primary immune cells in their functions.
7
Q
There are 3 components to the physical barriers made by the integument:
- know the layer and what they lead to
A
- Secretion: Wash away (and/or destroy) potential pathogens
- Hair: Keep potential hazards away form the skin surface
- Stratified squamous epithelium: Many closely interlocked layered which keep intruders out
- see diagram in lecture #36 slide 7
8
Q
Mucous membranes
- list the 2
- draw the diagram
A
Line the digestive, respiratory, urinary, and reproductive tracts… which all connect to the outside world.
They provide protection against foreign substances and pathogens
- Secretion
- Tight interlocking: Epithelial cells tied together by tight junctions and supported by fribourgeois basement membrane
-> draw out the diagram Lecture #36 slide 8
9
Q
Immune responses are meditated by…
A
White blood cells
10
Q
Both the innate and adaptive immune response rely on..
A
The activation and signalling of specialized immune cells
11
Q
White blood cells (WBCs) are responsible for both…
A
Both types of immune response
12
Q
Is WBCs only found in blood?
A
NO it is not ONLY found in blood
13
Q
White blood cells are born in..
A
Hematopoietic red bone marrow
14
Q
White blood cells can be divided based on:
A
- Function
- Anatomy
- Developmental history
15
Q
What are the components of the Immune responses mediated by WBCs?
A
- Detection/Recognition: of invaders of abnormality (ex: NK cell)
- Secretion: of chemicals that alter the local environment of signal to other cells (ex: Interferon alpha)
- Destruction: of foreign particles pathogens, and diseased cells (ex: free macrophages)
16
Q
Innate immune response
- list the cell and what do they look like?
A
Are nonspecific responses that react to any threat they detect they are present from birth.
List:
- Neutrophil
- Basophil
- Eosinophil
- Monocyte
- Macrophage
- Mast cell
- Natural killer
Exception:
- Dendritic cell is in both
- Lecture #36 slide 13
17
Q
Adaptive response
- list the examples
- and what do they look like?
- what is the exception
A
Are specific and powerful responses triggered by exposure to particular antigens. They must be ‘learned’ over the lifetime
- T lymphocyte
- B lymphocyte
Exception:
- Dendritic is both
- Lecture #36 slide 13
18
Q
Analogies of the levels of immune system
A
Physical/Chemical Barriers: Keep most things out
Innate Immunity: Front lines for most things that get in
Adaptive Immunity: Saved for the really precise tasks
19
Q
The lymphatic system consists of…
A
Vessels that move lymph through the body, and tissues that produce or house lymphocytes
20
Q
Lymph
A
Is a fluid connective tissue that resembles blood, but it lacks most of the cells and most of the plasma proteins
21
Q
The lymphatic system is NOT…
A
Synonymous with the immune system - it also has non-immune functions
22
Q
There are 2 main non-immune functions of the lymphatic system:
A
- Return of filtered fluid from ISF to plasma
- Transport of digested and absorbed lipids
- look at diagram on lecture #36 slide 18
23
Q
Lymphatic vessels are present in almost every tissue in the body but have key differences from blood vessels. What are the similarities?
A
- both have an endothelial wall around a lumen
- larger vessels have a smooth muscle layer and contain valves that keep lymph flowing one way
24
Q
Lymphatic vessels are present in almost every tissue in the body but have key differences from blood vessels. What are the differences?
A
- lymph capillaries have blind ends
- All lymph vessels are typically more permeable along their length
- there is no equivalent of a heart to create pressure gradient to move lymph; it relies on smooth muscle contraction (and skeletal muscle pumps)
25
Lymph’s are better carry… so it is found near the …
Lymph’s are must better at carrying lipids. That is why are at found more near the digestive system
26
The lymphatic system also consists of….
- lymphocytes
- lymph nodes
- lymphoid
27
lymphoid organs and lymphoid tissues all belong to the … and contain…
- immune system
- lymphocytes (a subset of WBCs)
28
Primary lymphoid structure
Involves in the production and maturation of lymphocytes
29
Secondary lymphoid structures
Contains mature and functional lymphocytes
30
Tissues:
Lack a distinct capsule (ex: lymphoid tissue)
31
Organs
Have distinct fibrosis capsule (ex: lymph nodes)
32
Lymphatic system is not synonymous with _______ because
Immune system because not all WBCs are lymphocyte
33
Lymphocytes
Are a developmental classification; all lymphocytes are come from lymphoid stem cells
34
All other WBCs develop from…
Myeloid stem cells (like RBCs and platelets)
35
Most (but not all) lymphocytes are associated with _________
Adaptive immune response
36
Draw a graph of the classes of lymphocytes
Note: no matter which way you try to divide WBC types, there will always be an exception that makes it hard to find a simple rule
- lecture #36 slide 21
37
Lymph nodes
Are encapsulated structures which are connected to lymph vessels and house mature lymphocytes
-> draw the diagram on lecture #36 slide 24
38
Lymph nodes monitor lymph for ___________, which can ________________
1. Possible antigens
2. Stimulate immune responses
39
Lymph within lymph vessels flows…
Into and through lymph nodes, which are often clustered at joints and where peripheral lymph vessels meet the torso
40
What are lymph nodes
- are filled with?
- have a ________ capsule
- B and T lymphocytes (plus some other WBCs)
- connective tissue capsule
41
Describe Lymph nodes and their function regarding stimulate immune response
- draw the diagram and what are the steps involved for this steps?
- Filter lymph
- act as staging posts for generating adaptive immune responses to antigens dented by the innate immune system
- see lecture #36 slide 25
42
Lymph leaving lymph nodes has been _______
Filtered
43
Activated lymphocytes
- draw the diagram
- That have acquired specific adaptive immune responses leave the lymph node through efferent vessels
- results to the circulation in they lymph
- lecture #36 slide 26
44
Macrophages in the medulla help…
Destroy pathogens that make it into the lymph vessels, before they reach the bloodstream
45
Not all mature lymphocytes are associated with… why?
- Lymph nodes - there are other secondary lymphoid tissues
- these tissue contain aggregation of lymphocytes that act like lymph nodes but possess structural differences
46
Spleen
- An organ with high amounts of lymphoid tissue that filters and monitors the blood
- like lymph nodes, it contains clusters of lymphocytes within its white pulp. which generate adaptive immune responses
- is a lymphoid organ (bc/ the spleen is surrounded by a capsule, but the organization of lymphocyte clusters is more similar to that seen in lymphoid tissue - like lymphoid tissue); it also has non-lymphoid functions, such as recycling old RBCs in its red pulp
- filters blood plasma, not lymph - it acts like a lymph node for the blood
47
Lymphoid noodles are aggregations of …
Lymphocytes that lack a distinct capsule.
They are also called “mucosa associates lymphoid tissue” or MALT
48
Lymphoid nodules
Are regions of lymphoid tisse that are typically associated with mucosa
49
Other researchers distinguished that many subtypes of MALT are mostly based on______ and other categorize MALT by the ________ ...
1. location
2. the structure of the aggregations
- refer to lecture #36 slide 28
50
Lymphoid nodules are distinguished from lymph nodes by their .....
location and their organization
51
What do both lymph nodes and lymph nodules contain?
B and T cells that generate adaptive immune response
52
Lymph nodules
- have no capsule and no afferent vessels
- are found in areolar tissue within mucous membranes
- their density is highest where there are many live pathogens in the lumen
53
What are the 2 sections cell-mediated immunity is dividing into?
Innate and adaptive immune response
54
Innate response
- what cells are involved in this response and what do they look like?
- Present form birth/ not learned
- general -> the same for every threat
- Lecture #37 page 4
55
Adaptive immune system
- what cells are involved in this response and what do they look like?
- learned response
- specific response
- lecture #37 page 4
56
What does cell-mediated immunity also involve?
- Acellular soluble factors, including cytokines and complements(a group of plasam proteins that contribute to anti-microbial deenses)
57
Acellular soluble factors
Are secreted molécules which are involved in immune response
58
Acellular soluble - Complement
- what does it look like
A group of plasma proteins that contributes to the anti-microbial defences
- lecture #37 page 5
59
Acellular soluble - Cytokine
- what does it look like?
- any signalling molecule that is used as part of cell-mediated immune responses
Diverse (chemically and functionally) and can be:
- paracine or endocrine
- acting on non-immune cells or by immune cells
- released by non-immune cells or by immune cells
- enhancing immune responses or suppressing them
Lecture #37 page 5
60
What are the 3 basic components of an innate immune response and explain them each.
1. Recognition: identifications of pathogens or abnormal cells
2. Resolution: destruction of pathogens, and diseased cells
3. Recruitment: structural and chemical changes that bring WBCs to the site
61
What can the innate immune response also be called?
- it’s divided into 2 phases. What are those phases and explain
Inflammatory immune responses
Phase 1: Immediate Response
- generated by cells and soluble factors already present in the local tissue
Phase 2: Induced Response
- occurs with the recruitment of WBCs (especially phagocytes) from blood circulation
62
What are the the 5 cardinal ( or hallmark) signs of inflammations?
- heat
- redness
- swelling
- pain
- loss of function
63
Resident WBCs (ex: Mast cells)
- recognize tissue damage and pathogen entry and release signalling molecules
Steps:
1. Mast cell is activated by chemicals released from damages epithelium
2. Mast cells degranulates releasing granule contents; histamine, heparin, and cytokines
- see the diagrams lecture #37 page 9
64
Chemokine
Cytokines that functions to attract WBCs to move toward it
65
What does the release of paracrine factors from mast cells lead to?
- what does this look like?
Structural and physiological changes in the local tissue
- these signalling molecules have many non-immune cell targets in local tissue. Promoting different processes
- lecture #37 page 10
66
The release of cytokines, (especially interleukins) into the bloodstream leads to?
- there are 2 examples
Can generate body-wide aspects of inflammatory response
Example 1: Interleukin 1 (IL-1) can reprogram the hypothalamic set point for temp, triggering fever
Example 2: interleukin 6 (IL-6) can stimulate proliferation of WBCs (especially neutrophils) in red bone marrow
- see the diagrams lecture #37 page 11
67
The release of paracrine and hormonal factors from mast cells leads to?
The recruitment of circulating WBCs through extravasions
Extravasation involves:
1. Changes in the endothelial wall (allowing WBCs to stick to it)
2. Chemotaxis of WBCs into the interstitial spaces
- lecture #37 page 13
68
Phagocytic myeloid cells
- what type of phagocytes are there?
- what does the diagram look like?
Resolve infection by engulfing and destroying pathogens
Phagocytes:
- Neutrophils
- Eosinophils
- Macrophages -> Monocyte -> fixed macrophages or free macrophages
Lecture #37 page 14
69
What are the different types of phagocytes and what do they respond to?
- draw the graph
Neutrophils: very abundant; the main cell type recruited during innate immune responses
Eosinophils: mostly phagocytoses pathogens that have already been targeted by antibodies
Macrophages: can be resident or recruited; involved in innate responses, removal of dead cell debris, and sometimes act as antigen-presenting cells (APC)
70
Pus
- Is a mixture of protein-rich fluid and dead leukocytes (mostly neutrophils) at a local site of infection
- is more common form bacterial infections than other types of infection, so it is not a reliable sign of an inflammatory response
71
Complement protein
- Are soluble immune mediators that assist in resolving microbial infection when activated
- complement proteins are synthesized by the liver, and circulate in blood plasma
72
what happens to complement protein when they are activated
They generate an enzyme cascade (somewhat analogous to the coagulation cascade) that can lead to pathogen death
- look at the digramme lecture #37 page 17
73
What is the core of the complement cascade? And what does it lead to?
- draw the diagram and explain each part
Is the activation of Complement C3, which leads to both inflammatory and direct-attack response
- lecture #37 page 18
74
How can the complement system be activated? There are 3 distinct pathways
- draw and describe the diagram
1. Classical Pathway:
-> C3 activated by integration with antibodies (requires an adaptive immune response
2. Lectin Pathway:
-> C3 activated by interaction with bacterial cell wall
3. Alternative Pathway:
-> Cab stabilized by Complement Factor P (properdin) - stimulated by bacterial secretions
- lecture #37 page 19
75
Describe the “road map” for innate immunity : Microbial infections
- remember the definition of the 3 basic components of an innate immune response
1. Recognition: Mast cells, complement system
2. Recruitment:
-> Cytokines - vessel dilation, permeability, chemotaxis and extravasation of WBCs
3. Resolution:
-> Phagocytosis - especially by neutrophils and macrophages
-> Lysis - by complement membrane attack complex
76
Natural Killer (NK) cells
- what does it look like?
- perform immune surveillance locating (and destroying) abnormal self cells
- can recognize abnormal cells either by unusual cell surface proteins (both infected and tumours) or through the secretion of a cytokine called ‘interferon alpha’
- lecture # 37 page 24
77
An abnormal ‘self cell’ is a body cell that is either:
1. Infected by a virus
2. Part of a tumour
78
Natural killer cells resolve infection by releasing substances that ….
- what are the steps and what does it look like?
Trigger cell membrane permeability and lysis
Steps:
1. Recognition and adhesion
2. Realignment of Golgi Apparatus
3. Secretion of Perforin
4. Lysis of Abnormal Cell
79
What can Natural Killer cells also release?
NK cells can also release a cytokine called tumour necrosis factor alpha which acts as a paracrine signal that cen induce apoptosis in tumour cells
80
Cytokines released form Natural Killer cells attract?
Phagocytes which remove the cellular debris
81
Interferon gamma (IFN-y)
- what does it look like?
Can act as a chemokine, attracting and stimulating macrophages (and other cells) to the site
-lecture #37 page 26
82
What is the ‘road map’ for innate immunity; Immune Surveillance
- remember the definition of the 3 components of immune response
1. Recognition: interferon-alpha, cell-surface molecules
2.Recruitment: Interferon-alpha, other cytokines, enhancing chemotaxis of NK cells
3. Resolution: Lysis (by perforin) and induction of apoptosis (by TNF - alpha)
83
When does adaptive immunity come into play?
Innate immunity unable to remove pathogen -> a “bat signal” is sent out to call for them -> proceed with adaptive immune response
84
What makes the adaptive immune system different than innate? (General)
Innate immunity is non-specific and genetically determined compared to adaptive immunity is acquired following antigen exposure
85
What makes the adaptive immune system different than innate? (Specific)
1. Specificity
- T and B cells are equipped with receptors that recognize a specific antigen
- activated lymphocytes direct their attack specifically at their cognate antigen and ignore other antigens
2. Memory
- Activated lymphocytes dived into effector or inactive memory cells
- memory cells mount a faster, stronger, and more efficient attack during subsequent antigen exposure
3. Versatility
- Each lymphocytes recognize a specific antigen
- People posses millions of lymphocytes
- Therefore, a massive diversity of antigens can be recognized by lymphocytes
4. Tolerance
- Ensures “self: tissue are ignored while “non-self” tissue are considered a threat
- Usually genetically established but can be induced by repeated antigen exposure
86
What is the “Big Picture” Overview of Adaptive Immunity?
- draw out the diagram
ーdescribe the key players
Key Players:
Antigens: are molecules that stimulate an immune response
Antigen-presenting cells: prepare and present antigens to lymphocytes
T cells: execute cell-mediated immunity to physical or chemicals destroy pathogens and infected cells
B-Cells: facilitate humoral immunity and produce antibodies that target antigens for destruction
-Lecture #38 page 6
87
Describe the components of the lymphocyte lifecycle
Lymphocyte lifecycle: maturation, selection, activation
Step:
1. Red bone marrow
-> production site of lymphocyte precursors
2. Thymus
-> Site of T cell selections, differentiation or death
3. Peripheral lymphoid organs and tissues
-> Site of immune cell surveillance, activation, and proliferation
4. Undergoes apoptosis weeks - years after production
88
Primary Lymphoid
Sites where lymphocytes are produced and mature
89
Secondary Lymphoid Structures
Sites where lymphocytes are activated
90
How do lymphocytes determine their target?
- Lymphocytes only recognize antigens where they are bound to MHC (major histocompatibility complex) molecules
- there are 2 difference MHC molecules:
-> MHC class 1 and MHC class 2
- when antigen is present by an MHC molecule, lymphocytes learn to direct their attack against that specific antigen and nothing else
91
Where are Intracellular antigens presented?
On MHC class 1
92
Intracellular antigens
- ex: from viral or bacterial infections
- undergoes processing and presentation through the MHC class 1 pathways
- MHC class 1 molecule are located on teh surface of all uncleared cells
(Understand the diagram and chart in lecture #38 page 10)
93
Where are extracellular antigens presented?
On MHC Class 2
94
Extracellular antigens
Are phagocytoses, broken down into smaller peptides, then loaded onto MHC class 2 molecules for cell surface presentation
95
Where are MCH class 2 molecules exclusively located?
On the surface of antigen presenting cells and lymphocytes
- remember the diagram on lecture #38 page 11
96
T cell activation relies on __________ which relied on _________
1. Antigen recognition
2. Antigen presentation
97
What are MHC molecules recognized by
Receptors on T cell surface
98
T cell receptors
- are unique lymphocyte; different lymphocytes recognize different antigens
- are recognized by different types of T cells which generates differ to immune responses against the presented antigen
99
Different type of T cells recognize different MHC molecules
- knowing this what are the points you need to remember
- what does the diagram look like
- there are 350 types of cluster of differentiation (CD) markers that can exist on the surface of leukocytes
- CD types and number are different across all types of leukocytes
- CD markers play a role in antigen recognition, intercellular communication and environment sensing
- Lecture #38 page 13
100
What does antigen recognition and co-stimulation lead to?
CD8+ T-cell activation
101
CD8+ T cells
- what does it look like and its diagram?
- CD8 + T cells only recognize antigens when they are presented on MHC class 1 molecules
- When an inactive (naïve) CD8 + T cell interacts with an MHC class 1 molecule and recognized the bound antigen, the T cell becomes primed
- For full CD8+ T cell activation, it must receive a co-stimulation signal either from the infected cell or from its surrounding
- Activation stimulates T-cell division and differentia
102
Activated CD8+ T - cells become ?
- What does this looks like?
Cytotoxic T cells (Tc) or memory Tc cells
- Lecture #38 page 17
103
Tc cells
Directly attack and destroy infected cells by releasing cytotoxic (hence the name, cytotoxic T cells) that enter the infected cell and induce cell death
104
Memory Tc cells
are inactive Tc cells that remain in secondary lymphoid organs until a later antigen exposure
105
Regulatory T cells
Are CD4+, not CD8+!
106
Activated CD4+ T cells differentiate into?
active helper T cells, memory helper T cells, or regularity T cels
107
More about CD4+ T cells
- what does the diagram look like
1. Inactive CD4+ T cells becomes primed after binding and recognizing antigen presented by MHC-2
2. CD4 + T cell activation required co-stimulation
3. Activated CD4_ T cells divide and differentiate into helper T cells, memory T cells, or regulatory T cells
- lecture #38 page 18
108
How does regulatory T cells suppress immune activation?
By releasing inhibitory cytokines
109
Sensitization preceded ________
- what is the goal of sensitization?
- B cell activation
- Goal: coat B-cell surface with target antigen
110
B cell receptors (antibodies)
Bind antigens and initiates sensitization
111
B cells endocytose antigen
Load them onto MCH- 2 molecule and present them on cell surface
112
What happens when B cell is sensitized?
It will await helper T cell interaction for activation
- see the diagram lecture #38 page 19
113
What does B cells require for activation?
They need helper T cells for activation
114
Sensitized B cells
Search for a helper T cell that has encountered the same antigen
115
What happens upon antigen recognition by the helper T cell receptors?
The helper T cell released cytokines to induce B cell activation
- see the diagram on lecture # 38 page 20
116
May circulating helper T cells will attempt to ____
Bind the antigen-MHC-2 complex on the sensitized B cell
117
What happens after B cell activation?
- B cells divide and differentiate
118
Inactive memory B cells
- what does this diagram look like?
- it contains Active helper T cell -> activated B cell -> activate B cells -> plasma cells (etc)
Located to secondly lymphoid organs until subsequent antigen exposure when they will differentiate into plasma cells and secrete antibodies specific to antigen
Lecture #38 page 21
119
Antibodies
- what does it look like?
- Are small proteins made of plasma cells
- One antibody consists of 2 parallel polypeptide chains: a heavy chain and a light chain
-> each chain contains a variable segment and constant segments
-> the tips of the variable segments form a unique antigen-binding site
-> when the variable segments bind their target antigen, binding sites on the constant segments are accessible and bind complement protein or innate immune cells
- lecture #38 page 22
120
What mechanisms does the antibodies use to defend the body from pathogens?
- what does the an antibody look like?
1. Neutralization & preventing adhesion:
-> antibodies can prevent viral or bacterial infection through physically blocking the pathogen from binding to health cells
2. Complement:
-> Binding sites on antibodies bind complement protein which tags the antigen for degradation
3. Opsonization, phagocytes, and Inflammation:
-> Antibodies attract phagocytic cells that engulf the pathogen and stimulation release of pro-inflammatory cytokines
- lecture #38 page 24
121
What are the 5 different classes of antibodies, also called immunoglobulins (lgs)
- what do they all look like?
- how do they differ?
1. lgG: Accounts for 80% of all antibodies and protects against bacteria, bacterial toxins, and viruses
2. lgA: Found in glandular secretions and mucus membranes and prevent pathogens from accessing internal tissue
3. lgM: the 1st lg type to be released during infection and circules through blood and lymph
4. lgE: Associated with allergic reactions and binds mast cells, eosinophils, and basophils
5. lgD: located on B cells and binds extracellular antigen during sensation
Acronyme: GAMED
- Look: Lecture #35 page 25
- Immunoglobulins differ by their heavy-chain constant segments. Therefore, it is possible for a 5 class to react to the same antigens! But immunologically speaking, this is unlikely to actually happen
122
Adaptive immunity improves during ______
Subsequent infections
123
Primary Response: first antigen exposure - what does the wave look like?
- antibodies can’t be released until B cells become activated and differentiate into plasma cells
- antibody titre peaks around 1-2 weeks after intitula antigen exposure
- lecture # 38 page 26
124
Secondary response: subsequent antigen exposure
- what does the wave look like?
- the infected host already has the necessary tools!
- memory plasma cells quickly generate antibody titres that far surpass the primary response in both level and time
- since memory plasma cells can survive for 20+ years, this secondary response will après even if years pass before subsequent antigen exposure
- lecture # 38 page 26
