WINDOW 2 health & disease Flashcards
health
according to the WHO (world health organisation)
a state of complete physical, mental and social wellbeing and not just the absence of disease and infirmity
disease
a condition where part of an organism doesn’t function properly
communicable and what are they cause by
can be spread between individuals, caused by a pathogen
non communicable
can’t be transmitted between individuals
ebola (type of pathogen, symptoms, transmission method, method of reduction)
virus
haemorrhagic fever
spread via bodily fluids
reduced by isolation of individuals and sterilisation of areas
chalara ash dieback (type of pathogen, symptoms, transmission method, method of reduction)
fungus
leaf loss and bark lesions
carried through air by wind or when infected tree is moved
reduced transmission by removing young infected trees, replanting with a different species and restricting movement of ash trees
malaria (type of pathogen, symptoms, transmission method, method of reduction)
protist
red blood cell damage and liver damage
transmitted by mosquitoes, which act as vectors
transmission can be reduced by using mosquito nets and insect repellent
cholera (type of pathogen, symptoms, transmission method, method of reduction)
bacterium (vibrio cholerae)
diarrhoea
spread by contaminated water sources
reduced by ensuring access to clean water
tuberculosis (type of pathogen, symptoms, transmission method, method of reduction)
bacterium (mycobacterium tuberculosis)
coughing and lung damage
spread via air when individuals cough
reduced by avoiding public spaces, practicing good hygiene and sleeping alone in a well ventilated home
stomach ulcers (type of pathogen, symptoms, transmission method, method of reduction)
bacterium (helicobacter pylori)
stomach pain, vomiting and nausea
spread via oral transmission (eating or drinking)
reduced by access to clean water and hygienic living conditions
chlamydia (type of pathogen, symptoms, transmission method, method of reduction)
bacterium
no symptoms but can cause infertility
transmitted by bodily fluids
reduced by wearing a condom, screening individuals for treatment or avoiding sexual contact
HIV (type of pathogen, symptoms, transmission method, method of reduction)
virus
kills white bloods cells, causing immune system to deteriorate and eventually fail , and leading to AIDS
transmitted by infected bodily fluids
reduced by wearing a condom, not sharing needles and medication
virus
one or more strands of genetic material surrounded by a protein coat/capsid
viruses have to infect living cells to reproduce
what are the two virus pathways/life cycles
lytic pathway
lysogenic pathway
what happens in the lytic pathway (4)
1) virus attaches to host cell and genetic material is injected
2) proteins and enzymes in host cell are used to reproduce genetic material and make new viral components
3) virus components assemble
4) host cell lyses (bursts) releasing the new viruses which infect more cells
what happens in the lysogenic pathway (4)
1) the virus attaches to the host cell and genetic material is injected
2) injected genetic material is incorporated into the host cell’s genome
3) the viral genetic material is replicated each time the host cell is replicated, but the virus remains dormant
4) eventually, a trigger causes the genetic material to leave the genome and enter the LYTIC pathway
3 examples of physical barriers in the human body
- skin
- hairs and mucus in nose trap particles potentially containing pathogens
- cells in trachea and bronchi produce mucus trapping particles, the mucus is then wafted by cilia cells to the back of the throat where it can be swallowed
2 examples of chemical barriers in the human body
- stomach produced hydrochloric acid (very strong acid) that kills pathogens
- eyes produce lysozyme chemicals which kill bacteria on the eye’s surface
describe the response of the immune system to a pathogen (5)
- white blood cells look for pathogens
- B-lymphocytes find an antigen on a pathogen
- B-lymphocytes start to produce antibodies
- antibodies bind to the pathogen so that it can be found and destroyed
- antibodies are quickly reproduced - they flow around the body looking for all similar pathogens
what is the role of memory lymphocytes
when a new pathogen first enters the body, our immune response is slow as there aren’t many B-lymphocytes available to make the antibody required to match the antigen
as well as antibodies being produced, memory lymphocytes are made that remain and recognise an antigen
this means that the person has the ability to quickly respond to a 2nd infection more strongly (secondary immune response)
immunisation
injecting dead or inactive pathogens into the body
how does immunisation give the patient immunity (3)
the pathogens injected contain antigens which causes the body to make specific antibodies to destroy them
memory lymphocyte production is triggered
if live pathogens then enter the body, there are already memory lymphocytes present to trigger a secondary immune response
2 advantages of immunisation
- epidemics can be prevented if a large percentage of the population is immunised
- some diseases have been virtually wiped out due to immunisation programs
2 disadvantages of immunisation
- doesn’t always work
- you can have a bad reaction to a vaccine, although this is rare
herd immunity (may not be on test but seems to come up??)
when the majority of the population are vaccinated and healthy against a specific disease, a few are not vaccinated but well
a few are not vaccinated against the disease, and they are ill and contagious
the large number of vaccinated individuals gives protection
monoclonal antibodies
artificially created identical copies of a specific type of antibody
how do you make monoclonal antibodies (3)
fuse a mouse B-lymphocyte with a myeloma cell (tumour cell) to form a hybridoma
the hybridoma can be cloned to give lots of identical cells
these cells then divide quickly to produce the same antibodies which can be collected and purified
why do we use tumour cells to make monoclonal antibodies
lymphocytes don’t divide easily but tumour cells do
how are monoclonal antibodies used in pregnancy tests (structure of a test)
the hormone HCG is only produced during pregnancy
- the part of the pregnancy test stick you urinate on has antibodies FOR the hormone with blue beads attached
- the test strip (the other end of the stick) thee are more antibodies stuck down
how does a pregnancy test work if you are pregnant
the hormones bind to the antibodies on the beads
as urine moves along the stick, it carries the hormone and the beads
the beads and hormone bind to the antibodies on the test strip so the strip turns blue
how does a pregnancy test work if you are not pregnant
the blue beads are carried along but they have nothing to stick to so the test strip won’t turn blue
how can monoclonal antibodies be used to find blood clots
monoclonal antibodies have been developed to bind to the proteins in the blood clot
a radioactive element is attached so that a camera sensitive to radiation can locate the clot
potentially harmful blood clots can be removed before they harm the patient
tumour markers
proteins found on cancer cell membranes that aren’t normally found on normal body cells
how can cancer be diagnosed using monoclonalantibodies
(similar to identification of blood clots)
antibodies are labelled with a radioactive element and given to the patient through a drip
when antibodies encounter cancer cells they bind together
image taken with camera sensitive to radiation (eg. gamma camera) so that cancer cells appear as a bright spot
doctors can observe size, location and where the cancer is spreading to
how can cancer be treated using monoclonal antibodies
an anti-cancer drug is attached to the antibodies and given to the patient through a drip
the drug kills the cancer cells but not any normal body cells near the tumour
two advantages of cancer treatment with monoclonal antibodies
other cancer treatments damage nearby cells
there are fewer side effects for this kind of treatment
what do antibiotics do
inhibit processes in bacterial cells without damaging the host organism
why don’t antibiotics work on viruses
viruses are hard to treat without damaging the body’s cells
2 stages of drug development
pre-clinical testing
clinical testing
what happens in pre-clinical testing (2)
drugs are tested on human tissues and cells in a lab
drugs are then tested on animals to determine DOSAGE and TOXICITY
what happens in clinical testing (4)
drug is tested in a clinical trial to ensure no harmful effects on healthy people
the drug is THEN tested on people suffering to find the OPTIMUM dose
they are put into two groups and perform a blind or double blind trial
if all tests are met, the drug needs to be approved by a medical agency
what are risk factors linked to
an increase in the likelihood of developing a disease
lifestyle factors
risk factors which are a choice
how does smoking, acting as a lifestyle factor, increase risk of cardiovascular disease
nicotine
⮞ increases heart rate increasing blood pressure
⮞ high BP damages artery walls leading to a build up of fatty deposits, these restrict blood flow
increased risk of blood clots from smoking
restricting or blocking blood flow (from fatty deposit build up or blood clots) increases the chance of a heart attack or stroke
what are 4 potential lifestyle factors
smoking
poor diet
drinking too much alcohol
not getting enough exercise
malnutrition is caused by
a diet with too many/ few nutrients
risk of obesity is increased by
not doing enough exercise
having a diet high in fat and sugar
drinking too much alcohol increases the chance of
developing liver disease/liver cirrhosis
effects of non-communicable diseases
this puts pressure on the resources of local hospitals
effects on a country’s economy
overall effects on country’s development
overall effects of NCDs on country’s development
NCDs are common - high cost and occurrence can hold back a country’s development
effects of NCDs on a country’s economy
NCDs are costly for the NHS
sometimes if someone has an NCD they are unable to work which can negatively affect the economy too
how can NCDs place pressure on the resources of local hospitals
areas with high levels of obesity or excess liver consumption, means high occurrence of particular NCDs
what is BMI used for
used as a guide to decide if someone is underweight, normal, overweight or obese
BMI (formula)
BMI = mass / height^2 (in metres)
waist to hip ratio (formula)
waist circumference / hip circumference
what is the border for abdominal obesity in terms of waist to hip ratio for men and women
men: 1.0
women: 0.85
what causes cardiovascular disease
too much cholesterol in the blood can cause fatty deposits to build up in the arteries, restricting blood flow
deposits occur in areas with a damaged artery wall (due to high blood pressure)
fatty deposits trigger the formation of blood clots, blocking blood flow
what could restricted blood flow cause
lack of oxygen to the heart causing a heart attack
lack of oxygen to the brain can cause a stroke
what are 4 lifestyle changes that might be suggested if you have CVD
⮞ eat a diet low in saturated fat/ a balanced diet
⮞ exercise regularly
⮞ lose weight if necessary
⮞ stop smoking
what are 3 potential drugs to treat CVD
⮞ statins
⮞ anticoagulants
⮞ antihypertensives
what are three potential surgical procedures to treat CVD
⮞ stents
⮞ coronary bypass surgery
⮞ donor heart
what do statins do
reduce the amount of cholesterol in the bloodstream, slwoing down the rate at which fatty deposits form
side effects of statins
can cause aching muscles or liver damage
what do anticoagulants do
thins the blood allowing blood to flow through the blood vessels more easily and making blood clots less likely to form
side effects of anticoagulants
can cause excessive bleeding if in an accident
what do antihypertensives do
reduce blood pressure, helping to prevent damage to blood vessels
side effects of antihypertensives
can cause headaches and fainting
coronary bypass surgery
when a healthy vessel is taken from elsewhere and is used to bypass a blocked section
what is a stent
tubes inserted inside arteries to keep them open so that blood can pass through to the heart muscles, decreasing the risk of a heart attack
disadvantages of using stents (2)
an artery can narrow again as stents irritate it, causing scar tissue to grow
patient must take drugs to prevent blood clotting
donor heart
replacing the whole heart
disadvantages of a heart transplant/donor heart (2)
a new heart may not always start pumping properly
drugs (immunosuppressants) have to be taken to stop the body from rejecting the foreign heart - these drugs make you more vulnerable to other infections
what does an autoclave do
uses steam at a high pressure and temperature to kill any microorganisms present
what is an inoculating loop used for and how is it sterilised
used to transfer bacteria
loop should be sterilised by passing though a hot flame to kill an unwanted microorganisms
why should a Petri dish have a lid on it
to stop microorganisms in the air from getting in
how should liquid bacterial cultures be kept
should be kept in a culture vial with a lid
the lid should only be removed briefly when transferring bacteria, to prevent other microbes from getting in
how do you prepare the agar plates (core practical) (6)
1) petri dishes and agar gel sterilised in autoclave to kill bacteria present
2) pour sterile agar plates and all to set
3) using a sterile pipette, add a few drops of the microorganism solution to the agar to close the lid ; place the pipette in disinfectant
4) use a sterile spreader to spread microorganism solution
5) label and invert plate so unwanted additional bacteria can’t get in and to stop drops of condensation falling onto the agar
6) incubate at a maximum of 25°C to reduce potential growth of harmful microorganisms
investigating the effect of antiseptics and antibiotics on cultures of bacteria (method)
1) soak filter paper discs in different types of antibiotics using either different solutions of different concentrations of the solution
2) place paper discs onto an agar plate that has an even covering of bacteria, leaving some space between discs ; use a control
3) antibiotics should diffuse into the agar jelly - resistant bacteria won’t be affects but non-resistant strains will die, this leaves a clear area around the disc known as an inhibition zone
4) leave the plate for 48 hours at 25°C
5) the more effective the antibiotic is against the bacteria, the larger the inhibition zone will be
why should you use a control disc?
so that you can be sure that any difference in growth around discs is due to the effect of the antibiotic alone
area (formula)
π r²
