3.1 Communicable Diseases Flashcards

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1
Q

What are communicable diseases?

A

Communicable diseases are diseases that can be passes from one individual to another

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2
Q

What are pathogens?

A

Pathogens are microorganisms that cause infectious disease

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3
Q

What are the 4 types of pathogens?

A
  • Viruses
  • Bacteria
  • Fungi
  • Protists
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4
Q

How can pathogens spread?

A

Pathogens can spread by direct contact, water or air

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5
Q

How can the spread of pathogens be reduced?

A
  • Isolation
  • Vaccination
  • Hygiene
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6
Q

How do viruses work?

A

Viruses invade host cells. They then reproduce rapidly within those cells which causes the cells to burst. The cell damage is what causes us to feel ill

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7
Q

Measles?

A

Measles is a viral disease showing symptoms of fever and a red skin rash

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8
Q

Why are young children vaccinated against measles?

A

Young children are vaccinated against measles because it can be fatal if complications arise.

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9
Q

How are measles spread?

A

Measles are spread through the inhalation of droplets from sneezes and coughs

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10
Q

HIV

A
  • HIV is a virus that is initially a flu-like illness
  • HIV is spread by sexual contact or exchange of body fluids
  • Unless successfully controlled with antiretroviral drugs, the virus then attacks the body’s own immune cells.
  • AIDS is the condition resulting from long term HIV infection, where the body’s immune system becomes so badly damaged it can no longer defend against other infections or destroy cancer cells
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11
Q

Explain how HIV has to be treated?

A

HIV has to be treated at an early stage with antiretroviral drugs

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12
Q

How is HIV spread?

A

HIV is spread by sexual contact or exchange of body fluids such as blood (e.g. when drug users share needles)

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13
Q

Tobacco Mosaic Virus

A
  • Tobacco mosaic virus (TMV) is a pathogen that affects plants such as tomatoes.
  • It gives a distinctive ‘mosaic’ pattern of discolouration on the leaves which affects the growth of the plant due to lack of photosynthesis
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14
Q

Bacteria

A
  • Bacteria are prokaryotic cells
  • divide rapidly by binary fission
  • It either damages the cells directly or produces toxins that causes damage to body cells
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15
Q

In what conditions do bacteria reproduce?

A

Bacteria reproduce rapidly in warm, moist conditions with a good supply of oxygen

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16
Q

What is Salmonella

A
  • Salmonella food poisoning is spread by bacteria ingested in food, or on food prepared in unhygienic conditions.
  • In the UK, poultry are vaccinated against Salmonella to control the spread.
  • Fever, abdominal cramps, vomiting and diarrhoea are caused by the bacteria and the toxins they secrete.
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17
Q

Gonnorhoea

A

Gonorrhoea is a sexually transmitted disease (STD) with symptoms of a thick yellow or green discharge from the vagina or penis and pain on urinating. It is caused by a bacterium and was easily treated with the antibiotic penicillin until many resistant strains appeared. Gonorrhoea
is spread by sexual contact. The spread can be controlled by treatment with antibiotics or the use of a barrier method of contraception such as a condom

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18
Q

How do fungi work?

A
  • Fungi are single celled organisms that have a body made of hyphae (thread-like structures)
  • They then produce spores which then spread to other organisms
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19
Q

Rose Black Spot

A

Rose black spot is a fungal disease where purple or black spots develop on leaves, which often turn yellow and drop early. It affects the growth of the plant as photosynthesis is reduced. It is spread by water or wind. Rose black spot can be treated by using fungicides and/or removing and destroying the affected leaves.

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20
Q

Explain how malaria functions?

A
  • Malaria is a disease caused by protist pathogens
  • The disease is carried from host to host by mosquitoes, the vector, when it infects them by biting them
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21
Q

What does Malaria cause?

A

Malaria causes recurrent episodes of fever and can be fatal

22
Q

How can we control the spread of malaria?

A

We can control the spread of malaria by preventing the vectors, mosquitos, from breeding and by using mosquito nets to avoid being bitten

23
Q

Why do antibiotics not work on viruses?

A

Antibiotics do not work on viruses as they stay inside host cells and they are not living cells

24
Q

What do viruses need in order to survive?

A

A host cell

25
Q

What is a vector?

A
26
Q

What are non-specific defence systems?

A

Non-specific defence systems are designed to prevent any pathogen from entering the body and causing harm

27
Q

What are the 4 non-specific human defence systems?

A
  • skin
  • nose
  • trachea and bronchi
  • stomach
28
Q

How does the skin prevent pathogens from entering the body?

A
  • It acts as a physical barrier that prevents bacteria and viruses from reaching the tissues beneath
  • When the skin is cut, the platelets form a scab to prevent pathogens from getting in
  • The glands in the skin produce antimicrobial secretions to destroy pathogens
  • Healthy skin is covered with microorganisms that keep you healthy and act as an additional barrier for the entry of pathogens
29
Q

How does the nose prevent pathogens from entering the body?

A

The nose have hairs and mucus, which is a sticky substance that traps particles that may contain pathogens

30
Q

How does the trachea and bronchi prevent pathogens from entering the body?

A
  • The trachea and bronchi also secrete mucus that traps pathogens from the air
  • The lining of these tubes is covered in tiny hair like projections from the cells called cilia.
    The cilia sweep the mucus to the back of the throat where it is swallowed
31
Q

How does the stomach prevent pathogens from infecting the body?

A

The glands in the stomach wall contain hydrochloric acid, which destroys any pathogens in your food and drink, or from the mucus

32
Q

What does the immune system do?

A

The immune system tries to destroy any pathogen that passes through the non-specific defence system

33
Q

What are the 3 ways white blood cells can help to defend against pathogens?

A

White blood cells help to defend against pathogens by:
- Phagocytosis
- Antibody production
- Antitoxin production

34
Q

What are the two types of white blood cells?

A

Phagocytes and Lymphocytes

35
Q

How do phagocytes protect us from diseases?

A

Phagocytes protect us from disease by detecting and **engulfing*’ the pathogen. It then ingests the pathogen, by releasing enzymes to digest and destroy them so that they cannot make you ill

36
Q

What do lymphocytes do?

A

Lymphocytes produce antibodies and antitoxins

37
Q

What are antigens?

A

Antigens are proteins on the surface of pathogens

38
Q

Describe how antibodies are produced and how they protect us from disease?

A

Lymphocytes identify foreign antigens on the surface pathogens
* They then produce antibodies that are specific and complementary to the antigen on the surface of the pathogen
* The antibodies bind onto the pathogen, triggering the process to destroy it and preventing the antigens from causing harm
* The binding of antibodies causes pathogens to clump together, mating it easier for phagocytes to find and engulf the pathogen

39
Q

How does the production of antitoxins from lymphocytes protect us from disease?

A

Antitoxins counteract (cancel out) the toxins released by pathogens (such as bacteria)

40
Q

Explain how vaccination works

A
  • Vaccination involves introducing small quantities of dead or inactive forms of a pathogen into the body
  • This stimulates the white blood cells to recognise and produce antibodies that are completmentary and specific to this antigen.
  • The memory cells for this antibody remain in the body so that if the same pathogen re-enters the body, the white blood cells will be able to respond quickly and produce large amounts of the correct antibodies, preventing infection
41
Q

What is herd immunity?

A

Herd immunity is when a large percentage of the popuation is immune to a disease, so the spread of the athogen within the population becomes reduced as there are fewer people who can pass it on

42
Q

What are antibiotics?

A

Antibiotics, are medicines used to treat bacterial disease by killing infective bacteria inside the body, without damaging body cells

43
Q

________ bacteria should be treated by ________ antibiotics

A

Specific bacteria should be treated by specific antibiotics

44
Q

What is the benefit of antibiotics?

A

Antibiotics have greatly reduced deaths from infectious bacterial diseases

45
Q

What is the concern with antibiotics?

A

Strains of bacteria that are resistant to antibiotics are continuously evolving

46
Q

Why can antibiotics not kill viruses?

A

Antibiotics cannot kill viruses as they live inside host cells and it is difficult to develop an antibiotic that will kill a virus without damaging the cell at the same time

47
Q

Give one example of antibiotics?

A

Penicillin

48
Q

What are painkillers?

A

Painkillers are used to treat the symptoms of disease but do not kill pathogens

49
Q

How were drugs traditionally made?

A

Traditionally drugs were extracted from plants and microorganisms

50
Q

Give 3 examples of drugs that were traditionally extracted from plants and microorganisms

A
  • Digitalis is a heart drug that originates from foxgloves
  • Aspirin is a painkiller that originates from willow
  • Penicillin is an antibiotic that was discovered by Alexander Fleming from the Penicillium mould
51
Q

How are drugs currently made?

A

Drugs are currently synthesised by chemists in the pharmaceutical industry. However, the starting point may still be a chemical extracted from a plant.