More diseases Flashcards
1
Q
Name the non-specific defences of the body ?
A
- Skin
- Mucous membranes
- HCl/ acid in the stomach
- Lysozymes in tears and urine
2
Q
Explain how skin is a non-specific defence of the body ?
A
- It is a physical barrier that covers the whole body, preventing entry of pathogens
- It also produces sebum, an oily substance preventing/ inhibiting growth of pathogens
3
Q
Explain how mucous membranes is a non-specific defence of the body ?
A
- Airways of the respiratory system are lined by mucous membranes that secrete mucus
- This traps dust/ harmful microrgasnims and contains phagocytes removing pathogens
4
Q
What are the different expulsive reflexes ?
A
- Coughs/ sneezes
- Vomiting/ diarrhoea
5
Q
What are the effects of the expulsive reflexes ?
A
- Coughs/ sneezes eject pathogen-laden mucus from the gas exchange system
- Vomiting/diarrhoea expel contents of the gut along with infective pathogens
6
Q
Explain what happens during blood-clotting ?
A
- When there is a cut, platelets release substances which via a cascade of events results in the formation of fibrin
- This forms a network of fibres trapping platelets and forming a clot
7
Q
Explain what happens during wound repair ?
A
- The lot dries out forming a hard scab preventing entry of pathogens
- Epidermal cells below scab begin to grow sealing the wound permanently while damaged blood vessels regrow
- Collagen fibres are deposited to give new tissue strength
- Once new epidermis reaches normal thickens, scab sloughs off and wound is healed
8
Q
What is an inflammatory response ?
A
A localised response to pathogens resulting in inflammation
9
Q
What happens during an inflammatory response ?
A
During an inflammatory response, majorty of cells are activated in damaged tissue and release chemicals called histamines and cytokines
10
Q
What are the effects of histamines in an inflammatory response ?
A
- Make blood vessels dilate causing localised hear and redness ( raided temperature helps prevent pathogens reproducing )
- Make blood vessel walls more leaky so blood plasma is forced out as tissue fluid causing swelling and pain
11
Q
What are the effects of cytokines in an inflammatory response ?
A
- Attract white blood cells to site of infection where they dips of pathogens via phagocytosis
12
Q
Name the non-specific defences inside the body ?
A
Fevers
13
Q
What are the effects of fevers ?
A
- When pathogens invade, cytokine stimulate your hypothalamus to increase the body temperate above 37oC
- Higher temperature inhibits pathogen reproduction
- Specific immune system also works faster at higher temperature
14
Q
What are phagocytes ?
A
Phagocytes : Specialised white blood cells that engulf an destroy pathogens
15
Q
What are the two types of phagocytes ?
A
- Neutrophiles
- Macrophages
16
Q
Explain what happens during phagocytosis ?
A
- Pathogen produce chemicals that attract phagocytes
- Phagocytes recognise. non-human protein on pathogen ( antigen )
- Phagocytes engulf the pathogen and encloses it in a vacuole called a phagosome
- The phagosome combines with a lysosome to produce phagolysosomes
- Enzymes/ lysozymes from the lysosome digest and destroy the pathogen
17
Q
What is the role of cytokines during phagocytosis ?
A
- Phagocytes that have engulfed a pathogen provides cytokines which act as cell-signalling molecules, informing other phagocytes that the body is under attack and stimulate cells to move to the site of infection
- They also increase body temperature stemalting the specific immune system
18
Q
What are opsonins ?
A
opsonins are chemicals that bind to pathogens, ‘tagging’ the so they can be more easily recognised by phagocytes
19
Q
What is the difference between nucleophiles and macrophages ?
A
- It takes 10 minutes for europhiles to engulf and destroy bacteria
- Macrophages undergo a more complex process
20
Q
Explain the process of phagocytosis for macrophages ?
A
- When a macrophage has digested a pathogen, it combines its antigens with special glycoproteins Called major histocompatability complex ( MHC )
- The MHC complex moves pathogen antigens to macrophages own CSM becoming an antigen-presenting cell ( APC )
- These antigens now stimulate other cells involved in specific immune response
21
Q
Define the term ‘antibody’ ?
A
Antibody : A Y-shpaed glycoprotein called immunoglobulin which binds to a specific antigen on the pathogen/ toxin that has triggered an immune response
22
Q
Label and explain the structure of an antibody in this diagram ?
A
23
Q
What are antibodies made up of ?
A
They are made up of two identical polypeptide chains ( heavy chains ) and two shorter identical cells ( light chains )
24
Q
Explain features of antibody structure ?
A
- Chains are held together by disulphide bridges
- The binding site is an area of amino acids on heavy and light chains known as the variable region
- Binding site is a different shape on each antibody going the antibody its specificity
- Hinge region provides molecule with flexibility, allowing it to bind to two separate antigens
25
Name the different ways in which antibodies function ?
- The antibody of the antigen-antibody complex acts as an opsonin
- Antibodies act as agglutinins
- Antibodies can act as anti-toxins
26
Explain the effect of antibodies of the antigen-antibody complex acts as an opsonin ?
- The antibody of the antigen-antibody complex acts as an opsonin so the complex is easily engulf and digested by phagocytes
- Most pathogens can no longer effectively invade the host cells once they are part of an antigen-antibody complex
27
Explain the effect of antibodies acting as agglutinins ?
- Antibodies act as agglutinins causing pathogens carrying antigen-antibody complexes to clump together
- This helps prevent them spreading through the body and makes it easier for phagocytes to engulf a larger number of pathogens at the same time
28
Explain the effect of antibodies acting as anti-toxins ?
Antibodies can act as anti-toxins, binding to the toxins proceed by pathogens and making them harmless
29
What are the two types of lymphocytes ?
- B lymphocytes
- T lymphocytes
30
What is the difference between B and T lymphocytes ?
B lymphocytes mature in bone marrow while T lymphocytes mature in thymus gland
31
What are the different types of T cells ?
- T helper cells
- T killer cells
- T memory cells
- T regulator cells
32
What are the different types of B cells ?
- Plasma cells
- B effector cells
- B memory cells
33
What is the role of T helper cells ?
- They have CD4 receptors on their CSM which binds to surface antigens on APCs
- Produce interleukins ( cytokine ) which stimulate activity of B cells, increasing antibody production
- This stimulates production of other T cells and attracts/ stimulates macrophages to ingest pathogens with antigen-antibody complexes
34
What is the role of T killer cells ?
- They destroy the pathogen carrying the antigen
- They produce a chemical called perforin, which kills the pathogen by making holes in the cell membrane so it is freely permeable
35
What is the role of T memory cells ?
- They live for a long time and are part go the immunological memory
- If they meet an antigen a second time, they divide rapidly to form a huge number of clones of T killer cells that destroy the pathogen
36
What is the role of T regulator cells ?
- These cells suppress the immune system, acting to control and regulate it
- They stop the immune reposes one a pathogen has been eliminated, and ensure the body recognises self antigens and does not set up and autoimmune response
37
What is the role of plasma cells ?
They produce antibodies to a particular antigen and release them into the circulation
38
What is the role of B effector cells ?
They divide to form the plasma cell clones
39
What is the role of B memory cells ?
-They live for along time and provide immunological memory
- They remember specific antigens and enabled he body to make very rapid responses when a pathogen carrying that antigen is encountered again
40
What happens during cell mediated immunity ?
In cell-mediated immunity, T lymphocytes respond to the cells of an organism that have been changed in some way by antigen processing or by mutation and to cells from transplanted tissue.
41
Explain the process of cell mediated immunity ?
- Macrophages engulf and digest pathogens in phagocytosis. They process the antigens from the surface of the pathogen to form antigen-presenting cells (APCs)
- The receptors on some of the T helper cells fit the antigens. These cells become activated and produce interleukins
- This stimulates more T cells to divide rapidly by mitosis. They form clones of identical activated T helper cells that all carry the right antigen to bind to a particular pathogen
42
During mediated immunity, what may happen to the cloned T cells ?
- They can develop into T memory cells, which give a rapid response if this pathogen invades the body again
- Produce interleukins that stimulate phagocytosis
- Produce interleukins that stimulate B cells to divide
- Stimulate the development of a clone of T killer cells that are specific for the presented antigen and then destroy infected cells
43
What happens during humoral immunity ?
In humoral immunity the body responds to antigens found outside the cells and to APCs
44
Explain the process of cell humoral immunity ?
- Activated T helper cells bind to the B cell APC. This is clonal selection
- Interleukins produced by the activated T helper cells activate the B cells.
- The activated B cell divides by mitosis to give clones of plasma cells and B memory cells. This is clonal expansion.
- Cloned plasma cells produce antibodies that fit the antigens on the surface of the pathogen, bind to the antigens and disable them, or act as opsonins or agglutinins. This is the primary immune response
- Some cloned B cells develop into B memory cells. If the body is infected by the same pathogen again, the B memory cells divide rapidly to form plasma cell clones. These produce the right antibody and wipe out the pathogen very quickly, before it can cause the symptoms of disease. This is the secondary immune response.
45
Why do we fall ill ?
The symptoms are the result of the way our body reacts when the pathogens are dividing freely, before the primary immune response is fully operational
46
What is clonal selection ?
It is the point at which the B cell with the correct antibody to overcome a particular antigen is selected for cloning
47
What are autoimmune diseases ?
When the immune system stops recognising 'self' cells and starts to attack healthy body tissue
48
Name examples of autoimmune diseases ?
- Type 1 diabetes
- Rheumatoid arthritis
- Lupus
49
What body parts are affected by rheumatoid arthritis ?
Joints, especially in hands, wrists, ankles and feet
50
What is the treatment for rheumatoid arthritis ?
- No cure
- Anti-inflammatory drugs
- Steroids
- Immunosuppressants
- Pain relief
51
What is natural active immunity ?
Natural active immunity is immunity which results from the response of the body to the invasion of a pathogen
52
What is natural passive immunity ?
Natural passive immunity is the immunity given to an infant mammal by the mother through the placenta and the colostrum.
53
What is artificial active immunity ?
Artificial active immunity is immunity which results from exposure to a safe form of a pathogen, for example, by vaccination.
54
What is artificial passive immunity ?
Artificial passive immunity is immunity which results from the administration of antibodies
from another animal against a dangerous pathogen.
55
What are vaccines ?
Vaccine : a safe form of an antigen, which is
injected into the bloodstream to provide artificial active immunity against a pathogen bearing the antigen
56
What is possibly added to vaccines to ensure they are safe ?
Vaccines may contain:
- killed or inactivated bacteria and viruses
- attenuated (weakened) strains of live bacteria or viruses
- Toxin molecules that have been altered and detoxified
- Isolated antigens extracted from the pathogen
- Genetically engineered antigens
57
Explain the process of being given a vaccine to achieve artificial active immunity ?
- The pathogen is made safe in one of a number of ways so that the antigens are intact but there is no risk of infection
- Small amounts of the safe antigen, known as the vaccine, are injected into the blood.
- The primary immune response is triggered by the foreign antigens and your body produces antibodies and memory cells as if you were infected with a live pathogen
- If you come into contact with a live pathogen, the secondary immune response is triggered and you destroy the pathogen rapidly before you suffer symptoms of the disease.
58
What is an epidemic ?
Epidemic : When a communicable disease
spreads rapidly to a lot of people at a local or national level.
59
What is a pandemic ?
Pandemic : When a communicable disease spreads rapidly to a lot of people across a number of
countries
60
Explain the role of vaccines in the prevention of epidemics ?
- At the start of an epidemic, mass vaccination can prevent the spread of the pathogen into the wider population
- To prevent epidemics, vaccines often have to be changed regularly to remain effective
61
What is herd immunity ?
When a significant number of individuals within a population have become vaccinated, protecting those who have no immunity
62
Explain why maintaining biodiversity is important as possible sources of medicines ?
- Biodiversity is rapidly being lost around the world : destruction of rain forests, the loss of coral reefs and loss of habitats due to human activities
- It is important to maintain biodiversity is to make sure we do not destroy a plant, animal or microorganism which could give us the key to a life-saving drug.
63
List examples of medicines and their sources ?
64
What are personalised medicines ?
A combination of drugs that work with your individual combination of genetics and disease ( this science is called pharmacogenomics )
65
What are the benefits of using antibiotics ?
- Antibiotics interfere with the metabolism of the bacteria without affecting the metabolism of the human cells - selective toxicity
- After the discovery of penicillin, antibiotics started to be widely used and decreased the number of deaths caused by communicable diseases drastically
66
What are the risks of using antibiotics ?
- Due to their over-subscription, antibiotics are becoming less effective in treatment as more bacteria develop antibiotic resistance
67
name examples of high-profile antibiotic-resistant bacteria ?
- MRSA
- C. difficile
68
How can antibiotic-resistant infections be prevented ?
- BY minimising the use of antibiotics, ensuring that every course of antibiotics is completed to reduce the risk of resistant individuals surviving and developing into a resistant strain population
- Good hygiene in hospitals, care homes... in general
