Disease+Immunity Flashcards

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1
Q

What is disease

A

A condition that impairs the normal functioning of an organism

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2
Q

What is a pathogen

A

An organism that causes disease

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3
Q

What is a communicable disease

A

A disease that can spread between organisms

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4
Q

What does Tuberculosis affect and what pathogen is responsible for it

A

Animals, typically humans and cattle and is a bacterium

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5
Q

What does bacterial meningitis affect and what pathogen is responsible for it

A

Humans and bacterium

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6
Q

What does ring rot affect and what pathogen is responsible for it

A

Potatoes, tomatoes and is bacterium

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7
Q

What does HIV/AIDS affect and what pathogen is responsible for it

A

Humans and a virus

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8
Q

What does influenza affect and what pathogen is responsible for it

A

Animals including humans and is a virus

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9
Q

What does tobacco mosaic virus affect and what pathogen is responsible for it

A

Plants and virus

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10
Q

What does black sigatoka affect and what pathogen is responsible for it

A

Banana plants and a fungus

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11
Q

What does ringworm affect and what pathogen is responsible for it

A

Cattle and a fungus

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12
Q

What does athlete’s foot affect and what pathogen is responsible for it

A

Humans and a fungus

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13
Q

What does late blight affect and what pathogen is responsible for it

A

Potatoes/tomatoes and is a protoctist

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14
Q

What does malaria affect and what pathogen is responsible for it

A

Animals, including humans and a protoctist

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15
Q

What is direct transmission

A

When a disease is transmitted directly from one organism to another

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16
Q

What is indirect transmission

A

When a disease is transmitted from one organism to another via an intermediate such as air, water or food.

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17
Q

Examples of direct transmission

A

HIV through sexual intercourse or athlete’s foot via touch

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18
Q

Examples of indirect transmission

A

Late blight is spread when spores are carried between plants and malaria is spread between humans via mosquitoes as they act as vectors and spread it.

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19
Q

Three factors affecting disease transmission

A

Overcrowding, climate, social

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20
Q

Example of how overcrowding affects disease transmission

A

TB is increased risk with lots of people together in a small space as is spread by droplet infection which can remain in the air for long periods of time

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21
Q

Example of how climate affects disease transmission

A
  • Late blight is common during wet summers as spores need water to spread
  • Malaria is common in tropical countries as they are ideal conditions for mosquitoes
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22
Q

Example of how social factors affects disease transmission

A
  • Good healthcare as people are less likely to be diagnosed and treated for HIV and drugs are less likely to be available and the disease more likely to be spread
  • Good health education as helps to inform people how HIV is transmitted and how to avoid it
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23
Q

What are the primary non specific defense’s against pathogens in animals

A

Skin, mucous membranes, blood clotting, inflammation, wound repair, expulsive reflexes

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24
Q

How does skin act as a barrier to infection

A

Blocking pathogens from entering the body. Acts as a chemical barrier producing chemicals that are antimicrobial, can lower pH, inhibit the growth of pathogens

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25
Q

How does mucous membranes act as a barrier to infection

A

Protect body openings that are exposed to the environment, some secrete mucus a sticky substance trapping pathogens and contain antimicrobial enzymes

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26
Q

How does blood clotting act as a barrier to infection

A

It is a mesh of protein fibres that plug wounds to prevent pathogen entry and blood loss. They are formed by chemical reactions that take place when platelets are exposed to damaged blood vessels

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27
Q

How does inflammation act as a barrier to infection

A

It is triggered by tissue damage that releases molecules increasing the permeability of the blood vessels so they start to leak fluid into the surrounding area. This causes swelling and helps to isolate any pathogens that may have may have entered the damaged tissue. The molecule also causes vasodilation increasing blood flow to the affected area making it hot and brings WBC to infected area.

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28
Q

How does wound repair act as a barrier to infection

A

The skin is able to repair itself after injury preventing entry of the pathogen. The surface is repaired by the outer layer of skin cells dividing and migrating to the edges of the wound. The tissue below the wound then contracts to bring the edges closer using collagen fibres. Too many collagen fibres=scar.

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29
Q

How does expulsive reflexes act as a barrier to infection

A

Coughing and sneezing to expel foreign objects including pathogens using irritation.

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30
Q

What are the physical defenses against pathogens in plants

A

Waxy cuticle, cell walls and production of callose

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31
Q

How is the waxy cuticle used as a plant physical defenses

A

Produces a physical barrier against pathogen entry and also stops water collecting on the leaf reducing risk of infection

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32
Q

How is the cell walls used as a plant physical defenses

A

Form a physical barrier that are made past the waxy cuticle

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33
Q

How is the production of callose used as a plant physical defenses

A

It is a polysaccharide that gets deposited between plant cell walls and plasma membranes during times of stress (pathogen invasion). Callose deposition may make it harder for pathogens to enter cells and at the plasmodesmata limits the spread of viruses between cells.

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34
Q

What are the physical defenses against pathogens in animals

A

Produce antimicrobial chemicals and secrete toxic chemicals

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35
Q

How does the production of antimicrobial chemicals act as a chemical plant defence

A

They kill pathogens or inhibit their growth:
- Some plants produce saponins that destroy the cell membranes of fungi and other pathogens
- Some produce phytoalexins which inhibit the growth of fungi and other pathogens

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36
Q

How does the production of toxins act as a chemical plant defence

A

Reduces the amount of insect-feeding on plants and therefore reduces risk of infection by plant viruses carried by insects.

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37
Q

What are antigens

A

Molecules found on the surface of the cells that activates cells in the immune system as identifies the foreign body

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38
Q

What does the immune response involve

A

It involves specific (T and B lymphocytes) and non-specific stages

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39
Q

How does phagocytosis occur

A

1) A phagocyte recognizes the antigens on a pathogen

2) The cytoplasm of the phagocyte move round the pathogen, engulfing it. This may be made easier by the presence of opsonins

3) The pathogen in now contained in a phagosome

4) A lysosome fuses with the phagosome and the enzymes break down the pathogen

5) The phagocyte then presents the pathogen’s antigens. It sticks the antigens on its surface to activate other immune system cells. When a phagocyte does this is it acting as an antigen-presenting cell (APC)

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40
Q

What are opsonins

A

Molecules in the blood that attach to foreign antigens to aid phagocytosis. Some hide the negative charges on the membrane of the pathogen, making it easier for the negatively-charged phagocyte to get closer to the pathogen

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41
Q

What is a phagosome

A

A type of vesicle membrane that engulfs a pathogen

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42
Q

What are neutrophils

A

A type of phagocyte and the first WBC to respond to a pathogen as they move towards a wound in response to signals from cytokines.

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43
Q

What are cytokines

A

Proteins that act as messenger molecules and released by cells at the site of the wound.

44
Q

What are the different types of T lymphocytes

A

(T) helper, killer and regulatory cells

45
Q

What do T helper cells do

A

Release substance to activate B lymphocytes and T killer cells

46
Q

What do T killer cells do

A

Attach to and kill cells that are infected with a virus

47
Q

What do T regulatory cells

A

Suppress the immune response from other WBC to stop immune system cells from mistakenly attacking the host’s body cells.

48
Q

T lymphocytes activate….

A

B lymphocytes, which divide into plasma cells

49
Q

Phagocytes activate…

A

T lymphocytes

50
Q

What are T lymphocytes

A

Type of WBC whose surface is covered with receptors which bind to antigens presented by APC’s. They each have a different lymphocyte on it’s surface

51
Q

What is clonal selection

A

When a receptor on a T lymphocyte meets a complementary antigen it binds to it activating the T lymphocyte.

52
Q

What are B lymphocytes

A

Type of white blood cell covered in antibodies that bind to antigens to form an antigen-antibody complex

53
Q

What happens when an antibody on the surface of a B lymphocyte meets a complementary shaped antigen

A

It binds to it and along with substances from T helper cells it activates the B lymphocyte which is another form of clonal selection

54
Q

What happens when an activated B lymphocyte divides

A

It will occur by mitosis into plasma and memory cells which is another form of clonal expansion

55
Q

The process of cell signaling

A

A cell release a substance that binds to the receptors on another cell causing a response of some kind in the other cell

56
Q

Why is cell signaling important

A

It helps to activate all the different types of WBC. For example, T helper cells interleukins that bind to receptors on B lymphocytes activating the B lymphocytes the T helper cells are signaling to the B lymphocytes that there’s a pathogen in the body

57
Q

What do plasma cells make

A

More antibodies to a specific antigen

58
Q

What are plasma cells

A

Clones of the B lymphocytes and secrete loads of the antibody specific to the antigen into the blood which bind to the antigens on the surface of the pathogen forming lots of antigen-antibody complexes

59
Q

Structure of antibodies

A

Glycoproteins made from four polypeptide chains - two heavy and two light chains each with a variable region and a constant region

60
Q

What do the variable regions do and how do their shape relate

A

Form the antigen binding sites and their shape is complementary to a particular antigen. The variable regions differ between antibodies

61
Q

What does the hinge region do

A

Allow flexibility when the antibody binds to the antigen

62
Q

What do the constant regions do

A

Allow binding to receptors on immune system cells such as phagocytes. It is the same in all antibodies

63
Q

What are disulfide bridges

A

A type of bond that holds the polypeptide chains of the protein together

64
Q

How do antibodies help to clear infection

A

Agglutinating pathogens, neutralizing toxins and preventing the

65
Q

How does agglutinating pathogens help to clear infection

A

Each antibody has two binding sites so an antibody can bind to two pathogens at the same time leading to the pathogens becoming clumped together. Phagocytes then bind to the antibodies and phagocytose lots of pathogens all at once. This is known as agglutinins

66
Q

How does neutralizing toxins help to clear infection

A

Toxins have different shapes and antibodies called anti-toxins can bind to the toxins produced by pathogens preventing the toxins from affecting human cells. The toxins are therefore neutralized and the toxin-antibody complexes are also phagocytosed.

67
Q

How does preventing the pathogen binding to human cells help to clear infection

A

When antibodies bind to the antigens on pathogens, they may block the cell surface receptors that the pathogens need to bind to host cells. This means the pathogen can’t attach to or infect the host cells.

68
Q

What happens when a pathogen enters the body for the first time

A

The antigens on its surface activate the immune system called the primary response.

69
Q

Why is the primary response slow

A

There aren’t many B lymphocytes that can make the antibody needed to bind to it. Eventually the body will produce enough to overcome the infection however, meanwhile the infected person will show symptoms of the disease

70
Q

What happens after being exposed to an antigen in the primary response

A

Both T and B lymphocytes produce memory cells which remain in the body for a long time

71
Q

What do Memory T lymphocytes remember

A

Remember the specific antigen and will recognize a second time round

72
Q

What do Memory B lymphocytes record

A

The specific antibodies needed to bind to the antigen

73
Q

What happens during a secondary response

A

If the same pathogen reenters the system produce a quicker, stronger immune response. Clonal selection happens faster as Memory B lymphocytes are activated and divide into plasma cells that produce the right antibody to the antigen. Memory T lymphocytes are activated and divide into the correct type of T lymphocytes to kill the cell carrying the antigen. This happens before any symptoms show.

74
Q

Difference table of primary and secondary response

A

Pathogen:
P = Enters for 1st time
S = Enters for 2nd time

Speed of response:
P = Slow
S = Fast

Cells activated:
P = B and T lymphocytes
S = Memory cells

Symptoms:
P = Yes
S = No

75
Q

What is a blood smear

A

A sample of blood smeared over a microscope slide

76
Q

What are you likely to see in a blood smear

A

RBC, WBC and platelets

77
Q

How do you spot a RBC in a blood smear

A

They do not have a nucleus

78
Q

How do you spot a neutrophil in a blood smear

A

Looks like three interconnected blobs and the nucleus is multi-lobed which grainy cytoplasm

79
Q

How to spot a lymphocyte in a blood smear

A

It is small and the nucleus is very large

80
Q

How to spot a monocyte in a blood smear

A

Biggest WBC and a type of phagocyte with a kidney bean shape nucleus and a non-grainy cytoplasm

81
Q

What is active immunity

A

When your immune system makes its own antibodies after being stimulated by and antigen

82
Q

What are the two types of active and passive immunity

A

Artificial and natural

83
Q

What is active natural immunity

A

Become immune after catching a disease

84
Q

What is active artificial immunity

A

When you become immune after you’ve been given a vaccination containing a harmless dose of antigen

85
Q

What is passive immunity

A

Get from being given antibodies made by a different organism

86
Q

What is passive natural immunity

A

When a baby becomes immune due to the antibodies it receives from its mother

87
Q

What is passive artificial immunity

A

When you become immune after being injected with antibodies from someone else

88
Q

Characteristics of active immunity

A
  • Requires exposure to antigen
  • Takes a while for protection to develop
  • Protection is long-term
  • Many cells are produced
89
Q

Characteristics of passive immunity

A
  • No exposure to antigen
  • Protection is immediate
  • Protection is short-term
  • Memory cells aren’t produced
90
Q

What happens when an organism’s immune system isn’t able to recognize self-antigens

A

The immune system treats the self-antigens as foreign antigens and launches an immune response against the organism’s own tissues.

91
Q

Examples of autoimmune diseases

A

Lupus - caused by the immune system attacking cells in the connective tissues causing painful inflammation. It can affect the skin, joints and organs

Rheumatoid arthritis - caused by the immune system attacking cells in joints causing pain and inflammation

92
Q

What is herd immunity

A

A large percentage of the population is vaccinated so there is not a likelihood of many catching it even if not everyone is vaccinated

93
Q

What may the substances in vaccines be

A

Antigens - free or attached to a dead or attenuated pathogen

mRNA - designed to code for antigens triggering memory cells to be made

94
Q

Define vaccination

A

The administration of a substance designed to stimulate the immune system

95
Q

Define immunization

A

The process by which you develop immunity

96
Q

What do routine vaccines include

A

MMR - measles, mumps and rubella given to children at 1 containing attenuated mmr viruses

Meningitis C - protects against bacteria that cause Meningitis C. Given at 3 months and boosters at 1 and teenagers

97
Q

What are antibiotics

A

Chemicals that kill or inhibit the growth of bacteria (bacterial infections)

98
Q

History of antibiotics

A

Penicillin became the first antibiotic by Alexander Fleming and they became widespread during the Second World War now meaning we have been able to deal with bacterial infections easier

99
Q

Problem of antibiotic resistance

A

There is genetic variation in a population and therefore genetic mutations occur.

100
Q

The antibiotic resistant bacteria MRSA

A

Meticillin-resistant staphylococcus aureus causes serious wound infections and is resistant to several antibiotics

101
Q

The antibiotic resistant bacteria clostridium difficle

A

Infects digestive system causing problems in people who have already been treated with antibiotics. Thought that the harmless bacteria that are normally present in the digestive system are killed by the antibiotics

101
Q

Why are doctors being encouraged to reduce their use of antibiotics

A

To reduce the risk of antibiotic resistance occuring

102
Q

Why does biodiversity need to be protected in medicine

A

So that the drugs that are manufactured naturally can still be made such as penicillin from fungus

103
Q

What are personalized medicines

A

Tailored to an individual’s DNA to precut how you will respond to different drugs and prescribe the most effective

104
Q

/What is synthetic biology

A

Using technology to desgin and make artificial proteins, cells and microorganisms