B6.3 pt1: monitoring&maintaining health Flashcards
(70 cards)
1
Q
What is a disease?
A
A condition caused by any part of the body not functioning properly. Can be physical or mental. Grouped into communicable and non-communicable.
2
Q
When do you have good health?
A
When you have no disease.
3
Q
Characteristics of communicable diseases
A
- can be spread between organisms
- mostly caused by microorganisms
- cause disease when they enter an organism
4
Q
What are the 4 main pathogens?
A
Bacteria, viruses, protists, fungi
5
Q
Bacteria
A
Very small cells which rapidly reproduce. Make you feel ill by producing toxins that damage cells and tissues. 1/100th the size of body cells.
6
Q
Viruses
A
Non-living, not cells. Replicate themselves inside the infected organisms cells, then burst, releasing the viruses. 1/100th the size of a bacterium.
7
Q
Protists
A
Eukaryotic single celled and vary in size. Parasites.
8
Q
Fungi
A
Some are single celled, some have a body made up of thread-like structures called hyphae. Hyphae can grow and penetrate human skin and plant surfaces. Can also produce spores, meaning further spread.
9
Q
Characteristics of non-communicable diseases
A
- can not be spread
- causes: poor diet, obesity, inheritance, body processes not operating correctly
10
Q
Interactions between HPV and cervical cancer
A
Human Papilloma Virus (HPV) can cause cell changes that lead to cervical cancer.
11
Q
Interactions between HIV and AIDS
A
Human immunodeficiency virus (HIV) causes Acquired immune deficiency syndrome (AIDS). It weakens a person immune system, making it easier for other microorganisms, like the TB causing bacteria, to cause disease.
12
Q
How are communicable diseases spread in animals?
A
Must enter body, e.g.
- cuts in skin
- digestive system
- respiratory system
- reproductive system
13
Q
How are communicable diseases spread in plants?
A
- through the soil and water they grow in
- vectors like insects
- direct contact of infected sap
- wind blows fungal spores or infected seeds
14
Q
What is the incubation period?
A
The time delay between the pathogen entering the body and the symptoms
15
Q
How do pathogens cause disease?
A
The rapid reproduction of pathogens means that as they grow they cause cell damage, possibly producing toxic waste products
16
Q
Describe viral replication
A
- virus attacks cell
- inserts its genes
- tells the nucleus to copy its genes creating new viruses
- cell bursts, releasing new viruses and destroying the cell
17
Q
What is the incidence of disease?
A
The rate at which new cases occur in a population over a period of time
18
Q
Monitoring diseases
A
- studies last long periods of time, involving many people
- outcomes provide evidence for effectiveness of disease treatments or prevention techniques
19
Q
How do you prevent spread of disease in humans?
A
- cover mouth and nose when coughing and sneezing
- not touching infected people or objects
- using sexual protection
- not sharing needles
- general good hygiene: washing hands, cooking food properly, drinking clean water, protection from animal bites
20
Q
How do you prevent the spread of disease in plants+animals?
A
- burning diseased plant material
- drug treatment of animals
- whole herds slaughtered
- not moving livestock
- chemical dips installed on farms to kill pathogens on footwear
- fungicides and animal vaccinations
21
Q
Describe athletes foot
A
- caused by group of parasitic fungi - dermatophytes
- ideal conditions (warm and humid) for multiplication
- symptoms: cracked, flaking, itchy skin
- treatment: antifunhak cream
- very contagious spread through direct and indirect contact
22
Q
Describe food poisoning
A
- caused by growth of bacteria in food
- symptoms: stomach pains, diarrhoea, vomiting, fever
- treatment: time, or drip to replace fluids in life threatening situations
23
Q
Different bacteria which cause food poisoning
A
- Campylobacter: raw meat, unpasteurised milk, untreated water
- Salmonella: raw meat, unwashed veg, unpasteurised milk
- E.coli: raw + undercooked meats, unpasteurised milk + dairy products
24
Q
STIs caused by bacteria
A
Chlamydia: causes pain while urinating and genital discharge
Gonorrhea: causes burning pain while urinating and vaginal discharge
Both treated with antibiotics
25
STIs caused by viruses
Genital herpes: causes painful blisters or sores
HIV: causes weakened immune system often resulting in AIDS
No cures, by HIV symptoms controlled with antiretroviral drugs.
26
How are STIs spread?
Sexually transmitted infections are passed through bodily fluids or skin-on-skin contact. Hard to recognise, easy spread, condoms prevent
27
Describe HIV/AIDS
- HIV invades white blood cells + reproduces in cells
- cannot produce antibodies, weakening immune system
- body becomes target of everyday infections + cell changes that cause cancer
- final stage = AIDS: body can no longer fight life-threatening infections
28
Describe Tobacco Mosaic Virus, TMV
- viral plant disease - makes leaves discoloured
- prevents chloroplasts forming, stunting growth
- lowers quantity + quality of crop but usually doesn’t kill
- prevent spread by removing infected plants and washing hands and equipment between planting + resistant crops should be planted in previously infected areas
- affects tobacco plants, tomatoes, peppers, orchids etc
29
Describe Barley Powdery Mildrew
- fungal disease (Erisiphe graminis)
- symptoms: white powdery spots on leaves and stems, reduced growth, early leaf drop off, reduced crop yield
- grows well in high humidity and warm temp
- survives between seasons, releases spores, wind spread
- controlled through fungicide
30
Describe Crown gall disease
- bacterial disease (Agrobacterium tumefaciens)
- bacteria have large tumour inducing plasmids contains genes that cause the disease
- affects many, e.g. roses, fruit, nut trees
- bacteria enters plant through wound. Plasmid integrates into hosts genome causing greater production of growth chemicals leading to galls
- galls can encircle stem/trunk, cutting off sap flow, stunting growth, leads to death
- prevent spread by destroying + removing infected plants. avoid planting in same area for 2 years until bacteria die out due to lack of host plant.
31
What are physical and chemical plant defences?
Physical: physical barriers preventing microorganisms entering
Chemical: substances secreted by the plant that kill microorganisms
32
Describe the leaf cuticle (physical defence)
- waxy cuticle covers epidermal cells
- prevents water loss + pathogens from direct contact with epidermal cells
- limits chance of infection
- thin in aquatic plants, thick in cacti
- fungal pathogens require water onleaf surface for spore germination BUT cuticle = hydrophobic (water repelling)
33
Describe the cell wall (physical defence)
- major defence against fungal + bacterial pathogens
- primary cell wall = structural support, cellulose fibres cross-linked with pectin forms a gel to sement cells together
- secondary cell wall = excellent structural barrier inside primary cell wall
- contains variety of chemical defences
34
Examples of chemical defences
- insect repellents
- insecticides
- antibacterial compounds
- antifungal compounds
- cyanide - toxic to most living things, made when cells are attacked
35
What are the methods of indentifying plant diseases?
In the field: observation + microscopy
| In the lab: DNA analysis + identification of antigens
36
Describe observation
Visual symptoms are easily observed, e.g. discoloured leaves etc
37
Describe microscopy
Since many visual symptoms of different diseases are similar, microscopy is used to identify a pathogen. Can only be identified once the symptoms become apparent (in the field).
38
Describe DNA analysis
Plant pathogens have a unique genome which can be identified with DNA fingerprinting. The DNA profile of an unknown pathogen is compared with a known one. If a match is found, accurate diagnosis is made. It can identify individual strains of microorganisms, even before the pathogen causes significant crop damage.
39
Describe the identification of antigens
Plant pathogens carry specific antigens on their surfaces. Can be identified through chemical analysis. Can be identified before significant crop damage is caused.
40
What are platelets?
Help blood to clot, small fragments from cells, made in bone marrow, carried around the body in blood plasma. Main infection barrier to prevent pathogens entering the body.
41
How does the skin form a scab?
- skin is cut and starts to bleed
- platelets change the blood protein fibrinogen into fibrin, forming a network of fibres in the cut
- red blood cells are trapped in the fibres, forming a blood clot
- clot hardens to form a scab, keeping the skin clean and time to heal. Eventually falls off.
42
What are white blood cells?
The immune systems main form of defence when pathogens do enter the body.
43
What are phagocytes?
Engulf microorganisms, then make enzymes to digest the microorganisms.
44
What are lymphocytes?
Make antitoxins or antibodies
45
What are antibodies?
Complementary proteins that bind to antigens on the surface of the microorganisms. Once bound, a phagocyte can ingest+destroy the pathogen - specific defence
46
What happens after the lymphocyte makes a new antibody?
Memory cells remember the shape, so if this infection occurs again, then white blood cells can make the antibodies much quicker. The body has immunity.
47
What is immunity?
When the pathogens are destroyed before the illness occurs.
48
Examples of non-specific body defences
- skin: difficult to penetrate + sweat/oils kill microorganisms
- stomach acid: kills pathogens in contaminated food/drink
- cilia + mucus in airways: mucus traps microorganisms, cilia move mucus up to throat where it’s swallowed
- nasal hairs: keep out dust and larger microorganisms
- tears: lysozyme destroy bacteria
49
What is a monoclonal antibody?
An antibody produced by a single clone of cells. Designed to target a specific type of cell, bind to antigens of target cell, killing it or preventing it from operating effectively.
50
Describe the production of monoclonal antibodies.
1. Genetically modified mice are injected with the required antigen
2. Their body produces the required antibodies
3. Antibody-producing lymphocyte cells are collected
4. These cannot survive outside the body so are fused with myeloma (cancerous cells) from the bone marrow which indefinitely reproduce, forming hybridoma cells.
5. Hybridoma cells reproduce - forming clones. Each clone produces the required antibody which is harvested.
51
Monoclonal antibodies in pregnancy testing
- pregnant women produce ‘human chorionic gonadotrophin’ hCG hormone
- monoclonal antibodies can be made that bind with hCG, found in urine, causing a colour change reaction
52
Monoclonal antibodies in detecting diseases
- some monoclonal antibodies act as markers, confirming a specific antigens presence
- bind to prostrate cancer cells, allowing early diagnosis
53
Monoclonal antibodies in treating diseases
- drugs that treat cancer can be attached to monoclonal antibodies
- antibodies find + bind to the cancer cells, delivering the drug to the cells
- range of cancers - breast, stomach and bowel
54
What is a vaccine?
Prevents people from getting a disease. Contains small amounts of weakened or dead versions of the disease-causing organism. Injected through a vaccination.
55
Describe vaccinations
- Vaccinations cause lymphocytes to produce antibodies to that antigen.
- Later encountering the real pathogen means that memory cells easily recognise it, producing antibodies much quicker.
56
What is herd immunisation?
If a large percentage of the population have been vaccinated, only a small percentage will be at risk from catching the disease + passing it on.
57
Issues with vaccinations
It saves many lives, however despite extensive testing they can very occasionally cause tragic results. Not risk-free.
58
Name some common childhood vaccinations
- MMR - measles, mumps and rubella
- Diptheria, polio, meningitis, whooping cough
- Tetanus
59
Describe antiseptics
- kill or neutralise all types of pathogen
- do not damage human tissue
- different types act on different microorganisms, e.g. bacteria as a common source of infection
- examples: alcohol, iodine
60
Describe antivirals
- drugs that destroy viruses, usually by preventing their replication
- e.g. it treats influenza, hiv, herpes, hepatitis B
- specific
- it’s activity may include: blocking virus from entering a host cell, preventing virus from releasing genetic material, preventing virus from inserting its genetic data into host cells DNA.
61
Describe antibiotics
- drugs that kill bacteria without damaging cells
- several types
- different bacteria identified through blood or stool samples sent to a lab. Grown on an agar plate + treated with different antibiotics to see the most effective. Drug is prescribed
- ‘halo’ around discs where bacteria growth is prevented
62
What is the zone of inhibitation?
The region/halo around discs where bacteria growth is prevented. The larger the zone, the more effective the antibiotic.
63
What are aseptic techniques?
Prevent foreign microorganisms from being introduced into a test sample. Minimises the risk of cross-contamination. Ensures the environment and apparatus are sterile = free from microorganisms.
64
Describe some aseptic techniques
- wash working areas with alcohol before + after working = to ensure no microorganisms are present in working area
- wear gloves if at risk of working with pathogens = prevent microorganisms passing from sample to skin
- autoclave glassware + apparatus before + after use = sterilise apparatus, preventing unwanted contamination of sample
- work close to Bunsen burner flame = prevent unwanted microorganisms falling into open sample
- flaming a wire loop by heating over a Bunsen burner flame until red = ensure wire loop remains sterile, most common medium of transferring microorganisms
65
What is preclinical testing?
When scientists find a potentially useful substance (after computer modelling), lab tests are performed to see its behaviour, including testing on live cells, bacteria + tissue colonies.
66
Stages of drug development
1. Animal testing (2 species needed)
2. Human testing - clinical testing - 3 stages
3. Approval of drug if all tests are positive
4. After approval, it is continued to be monitored, to see any unexpected side effects or problems in certain categories of people.
67
What are the 3 stages of clinical testing?
a) healthy volunteers - to look for unexpected side effects
b) small sample of volunteers with condition
c) large sample of volunteers with condition and placebo testing
68
What is the placebo effect?
When people feel better because they expect to feel better as a result of medicine. Used in clinical trials.
69
What is a double blind trial?
Drug is given to some patients while others get a drug replica with no active ingredients (placebo). To overcome the placebo effect, neither the doctors nor patients know which one they have received, until the test is over.
70
3 R’s of animal testing
Reduction: using smallest number of animals possible
Refinement: improving experiments to avoid unnecessary suffering + improve animal care
Replacement: where possible, replacing the use of animals with other examples like cell cultur or computer models.
