Lecture Two Flashcards
(39 cards)
1
Q
What is the immune system?
A
- a collection of organs, vessels, cells and molecules
- a system in constant motion and change (not static)
- a system with access to virtually every part of the body
2
Q
What does the immune system do?
A
- monitors molecular shapes within body
- distinguishes between self and nonself antigens
- protects us from infection
- speeds up recovery from infection
- helps us maintain adequate relationship with environment we live in
3
Q
What does the immune system respond to?
A
Molecular shapes. Either
- Because they are strange shapes
- Because they are familiar shapes in strange contexts
4
Q
What are antigens?
A
Molecular shoes the immune system recognises
5
Q
List some sources of antigens
A
Viruses, Bacteria, Parasites Dust particles, Cells From other people
6
Q
What can function as an antigen?
A
Anything big enough and greater than a certain complexity
7
Q
What is innate immunity?
A
- Non specific immunity
- first line barrier
- not improved by repeated antigen exposure
- consists of physical barriers and biochemical barriers
- if breeched, stimulates adaptive immunity
8
Q
What are some biophysical barriers to microbes?
A
Skin
Cilia
9
Q
What are some biochemical barriers to microbes?
A
Lysozyme in tears,
HCl in stomach
10
Q
What are commensal organisms and what is their purpose?
A
- Organisms that live in harmony with its host.
- bacteria in gut, vagina
- compete with foreign microbes for resources so they don’t survive
- component of innate immunity
11
Q
What does the innate system do when surface barriers are breeches?
A
- local innate immune factors (phagocytes and complement system) will inhibit microbe multiplication
- attempt to limit damage it causes
12
Q
What are phagocytes ?
A
- Neutrophils
- sometimes called polymorphonuclear leukocyte s
- ingest and digest foreign material
- have surface receptors that recognise common cell wall components of many types of bacteria
13
Q
Explain phagocytosis
A
- the process of phagocyte ingesting and digesting foreign material
- Neutrophil comes into contact with bacteria and adheres to it
- Adherence activates neutrophil to fold membrane around bacterium
- Bacterium is taken into a vesicle inside neutrophil
- Phagosome is formed
- Neutrophil releases packets of digest enzymes
- Bacteria is digested
- Neutrophil releases degraded products
14
Q
What is the complement system?
A
- component of innate immunity
- a series of ~20 blood proteins which can diffuse out of the bloodstream into tissue spaces of our bodies to limit infections (particularly bacterial)
15
Q
Describe the process of the complement system
A
- First complement components bind to bacterial antigen
- Activates other complement components
- Other complement components increase vascular permeability, opsonate bacteria, lyse bacterial cell walls, and release chemicals
All which aim to facilitate phagocytosis
16
Q
What does increasing vascular permeability do?
A
Helps white blood cells get to site of infection quicker
17
Q
What does the release of chemicals do?
A
Attracting neutrophils to the site
A.k.a chemotaxis
18
Q
What is opsonisation?
A
Coating the foreign material
19
Q
What does opsonisation do?
A
Makes foreign material more readily phagocytosed
20
Q
What does lysis do?
A
Breaches integrity of bacterial cell walls
21
Q
How does immune system recognise antigens?
A
- immune system has molecular recognition structures
- called receptors
- act as hands
- immune system uses receptors to sense outside world
22
Q
Where are receptors found?
A
On the surface if cells of immune system (cell surface receptors)
23
Q
Where are soluble receptors found?
A
In the fluids of the body
24
Q
What are the most common class of soluble receptors called?
A
Antibodies
25
What is immunological memory
Immune system has adapted to a certain antigen in such a way that it will respond much more rapidly and vigorously if it meets the same antigen
26
What is adaptive immunity
- Specific immunity
| - Immunity which is improved my repeated exposure
27
What is acquired immunological tolerance
The state of induced antigen specific immunological unresponsiveness
28
What are the two fundamental processes that living, a process, conserves?
1. Autopoiesis, generating self. All living things continue to build themselves somewhere,
2. Adaptation. They maintain their relationship with things outside themselves
29
Name the two types of receptors
Soluble receptors
cell surface receptors
30
What are soluble receptors
(antibodies) binding of antibody to virus allow other molecules in the body to recognise. Cells are neutralised.
31
What are cell surface receptors
the cell machinery is used by the virus. Proteins are made and some will appear on the surface of the cell. When cytotoxic lymphocyte binds to that virus infected cell, it will kill it and kill itself. Reduced the possibility of other cells being infected.
32
List some biophysical barriers to infectious agents. Give examples
1) skin
- most infectious agents cannot penetrate
- importance of this barrier particularly seen in patients with serious burns
- sweat and sebacceous secretions e.g. Lactic acid, fatty acid, generate direct inhibitory effects and low pH
2) cilia
- lining nasopharynx, wafts dust particles and infectious agents out ?
3) mucous in nose
- traps microbes
4) acid lining stomach
- acidic environment kills microbes
33
List some biochemical barriers to infectious agents. Give examples
1) Lysozyme in most secretions e.g. Tears,saliva
- enzyme is a bactericide - causes bacteria to fall apart
2) sebaceous gland secretions
- oil to generate direct inhibitory effects
3) commensenal organisms in gut and vagina
- compete with microbes (for resources etc so foreign microbes don't survive)
4) spermine in semen.
- bacteriacide
34
What are the components of the adaptive immunity
* Antibodies, complement cytokines
| * Lymphocytes, monocytes, antigen presenting cells
35
What are the components of innate immunity
* Lysozyme complement, acute phase proteins, interferon
* Phagocytes, natural killer cells.
* Lysozyme complement, acute phase proteins, interferon
* Phagocytes, natural killer cells.
* Lysozyme, complement, acute phase proteins, interferon
* Phagocytes, natural killer cells.
36
How does a phagocyte know what to eat?
Phagocyte can recognise what to ingest due to the complement system
A Series of 20 proteins that diffuse from blood stream to tissue spaces in our body act to limit infections ( particularly bacterial)
and causes an amplifying enzymatic cascade.
1. VASODILATION- change vascular permeability to facilitate neutrophil access to site of infection
2. CHEMOTAXIS- attracting neutrophils to site
3. OPSONIZATION - coating foreign material spot make it more readily phagocytised (bacteria more easily recognised)
4. LYSIS - breaching integrity of bacterial cell walls.
37
What is an epitope
part of an antigen molecule where an antibody attaches itself
38
What is a receptor
Molecular recognition structure to recognise antigens
39
Outline the relationship between primary contact, secondary contact ahd immunological memory
* Primary contact with a nonself antigen stimulates immune response
* Immune system builds up memory
* Secondary contact with same antigen leads to better immune response (before symptoms are noticed
