Topic 5 - Health and Disease Flashcards
WHO definition of health
the state of complete physical, metal and social well-being and not merely the absence of disease or infirmity
communicable disease
diseases that can spread between individuals and caused by pathogens
non - communicable disease
diseases that can’t spread between individuals, generally last for a long time and get worse gradually
susceptibility to other diseases
-if you are already infected with a disease you are more susceptible to others
- your body may become weakened by disease so less able to fight off others
what are the 4 main types of pathogens ( Big Vans Poor Fun)
- bacteria
- viruses
- protists
- fungi
how can pathogens be spread?
- by drinking or bathing in contaminated water
- inhaling droplets sneezed/coughed out by infected people
- through infected bodily fluids
- through animal vectors which are organisms that carry the disease
what are 3 bacterial diseases ( True Children Shout )
- tuberculosis
- cholera
- stomach ulcers
tuberculosis - how is it spread?
- caused by a bacteria and spread through infected droplets cough and sneeze
tuberculosis - symptoms and how to treat it / reduce the spread?
- symptoms include coughing and lung damage
- infected individuals should avoid public spaces and wear face masks, sanitise themselves appropriately
cholera - how is it spread?
- cause by bacteria and spread through drinking contaminated water sources
cholera - symptoms and how to treat it / reduce the spread?
- symptoms include diarrhoea and severe dehydration
- chemically disinfect water
stomach ulcers - how is it spread?
- caused by bacteria and spread through oral transmission ( eating or drinking infected food/water )
stomach ulcers - symptoms and how to treat it / reduce the spread?
- symptoms include stomach pain, nausea and vomiting
- having clean water supplies and disinfecting food preparation areas
ebola - how is it spread?
- caused by a virus and spread through coming into contact with bodily fluids of individual
ebola - symptoms and how to treat it / reduce the spread?
- symptoms include a haemorrhagic fever
- medical staff should regularly wash their hands and wear protective clothing. isolate infected individuals
chalara ash dieback - how is it spread?
caused by a fungus and spread through the air by wind or when you move infected ash tress to other areas
chalara ash dieback - symptoms and how to treat it / reduce the spread?
- symptoms include loss of leaves and deep lesions
- removing young, infected ash trees and replacing them
- restrictions on import and export of ash trees
malaria - how is it spread?
- caused by a protist and spread through an animal vector ( mosquitoes by feeding on animals )
malaria - symptoms and how to treat it / reduce the spread?
- symptoms include high fever
- spraying exposed skin with repellent
- sleeping under mosquito net
HIV - how is it spread
- caused by a bacteria and spread by exchanging bodily fluids such as blood and semen
HIV - symptoms and how to treat it / reduce the spread?
- over time it will destroy enough WBC to cause AIDS which makes you very vulnerable to most diseases
- wear a condom and don’t share needles when taking drugs
what is a virus?
a protein coat around a strand of genetic material
-they are parasites and only bind and insert their DNA into specific species
lytic pathway ( VIRULENT )
- virus binds onto specific host cell receptors + injects its genetic material into it
- virus uses proteins and enzymes of cell to replicate g.m and make viral components
- they assemble to form new viruses
- host cell lyses releasing virus and these infect more cells
lysogenic pathway ( GENOME )
- same step 1
- genetic material incorporated into genome of host cell
- viral genetic material gets replicated along with host DNA every division. atp the virus is dormant
- eventually, an environmental trigger causes the viral genetic material to leave genome and enter lytic pathway
what happens when our bodies get a cut?
- blood rapidly clots to seal blood vessels
- blood is reduced and entry of pathogens into bloodstream closed. chance of infection restricted
what are barriers?
physical and chemical barriers prevent the entry of pathogens into the body
physical barriers
- continous waterproof skin covers the body
- hairs and mucus in nose trap pathigens
- trachea and bronchi have cells that have cillia, which are hair like structures that waft mucus up the throat where it is swallowed
chemical barriers
- stomach produces hydrochloric acid which kills pathogens that make it that far
- produces lysozymes. these are enzymes that can kill bactreia and are found in tears where the kill pathogen near the eye
what is our immune system?
- our body’s second line of defence if pathognes overcome our physical and chemical barriers
- it mainly consists of WBC
phagocytes
these are WBC that engulf foreign cells and digest them, it’s a non-specific response
why do B-Lymphocytes only recognise 1 specific pathogen
- it is because they have the corect complimentary receptors to only 1 type of antigen which is unique to a pathogen
what role do B-Lymphocytes play?
- when b lymphocytes bind to the receptor of a pathogen it stimulates correct antibody production
- these antibodys bind onto antigen and label the pathogen for destruction
why is the body slow to fight against a new pathogen. why do we feel ill ?
- there aren’t many B-lymphocytes that make the correct antibodies that bind onto the new antigen
- the pathogen has time to multiply, infect our tissue and cause illness
what are memory lymphocytes
- they remain in the body for a long time and can ‘remember’ a foreign antigen
- made along with B-lymphocytes during primary immune system
why is the secondary immune response so effective ?
- if the same pathogen enters the body again the memory lymphocytes will immediately recognise the foreign antigen
- vast amounts of correct antiboies will immediately be produced
- which kills pathogens before its number increases sufficiently to cause disease
3 differences between primary and secondary response
- secondary response produces MORE antibodies
- secondary response produces antiboies FASTER
- delay betwen infection and producing antibodies is REDUCED
herd immunity
- even if some people aren’t immunised
- if a certain proportion of population are, theere are less people that can pass it on
- so the people that aren’t immunised are very unlikely to catch it
monoclonal antibodies
- antibodies made from lots of clones of the same B-lymphocyte
how to make monoclonal antibodies?
- a particular antigen is injected into a mouse
- mouse produces B-lymphocytes that make antibodies against it
- then, you fuse the B-lymphocytes with myeloma cells grown in the lab to make a hybridoma
- myeloma cells divide really quickly so these hybridomas dividie really quick to produce lots of monoclonal antibodies
what are monoclonal antibodies used for
- pregnancy tests
- diagnosing and treating cancer
- finding blood clots
what does a pregnancy test stick look like
- the part that you urinate on : contains antibodies to the antigen on HCG hormones attached to blue beads
- the test strip : contains same antibodies that are stuck on
what happens if you are pregnant?
- the HCG hormone binds to antibodies on the blue beads
- urine moves up the stick carrying the hormone attached to the blue beads
- they bind to antibodies on test strip. blue beads get stuck on the strip turning it blue
what happens if you aren’t pregnant?
urine still moves up the stick but there’s nothing to stick the blue beads onto the test strip so it doesn’t turn blue
control window
- shows that the test is working properly
- contains antibodies to the antibodies attached to blue beads
-control window should go blue both when a test is positive and negative
diagnosing/treating cancer
- monoclonal antibodies labelled with radioactive element or anti - cancer drug
- given to the patient, carried around the body
- when antibodies come into contact with cancer cells they bind to tumour antigens
- camera that can detect radioactivity used to take a photo to see where the cancer is
how do scientists discover drugs?
- computer design of molecules and screening of thousands of chemicals
- possible drugs synthesised in laboratory
preclinical testing - cells and tissues
- this is known as in vitro screening
- drugs tested on cell and tissue cultures
- can’t use this for drugs that affect multiple body systems
preclinical testing - live animals ( what 3 things are tested )
- finds out more about how it works in a whole living organisms
- efficacy (if it works in intended manner)
- toxicity
- best dosage
clinical testing stages :
- tested on healthy people
- small number of people suffering from the target disease, the dosage and number of people increase
what are placebos?
a substance that looks like the drug being tested but doesn’t actually do anything
why are placebos used?
so doctors can see the actual difference the drug makes - it allows for the placebo effect ( when the patient feels better even though they are taking a placebo )
blind trials
patient doesn’t know if they’re getting placebo or not
double-blind trials. why is it better?
- both doctor and patient don’t know who has the placebo or not
- this is so the doctors analysing the results aren’t subconsciously influenced by their knowledge
what are antibiotics?
antibodies inhibit processes in bacterial cells such as cell wall production without affecting the eukaryotic cells
why don’t antibiotics work on viruses?
- viruses are not cells so don’t contain any of the machinery needed for growth and reproduction
- viruses only reproduce inside host cell but antibiotics don’t target host cell so virus can survive
what are risk factors ?
- factors that are linked to an increase in the likelihood that a person will develop a certain disease
- the more risk factors you have for a disease, more likely you are to get it
lifestyle related risk factors for disease:
- smoking
- alcohol
- diet
- low levels of exercise
what is smoking a risk factor for and why?
- for cardiovascular disease ( heart attacks and strokes)
- nicotine in cigarette heart rate which increase B.P
- high B.P damages artery walls contributing to build up of fatty deposits
- this restrict blood flow and oxygen so increases chance of heart attack or stroke
why is smoking a risk factor for cancer as well?
- contains chemicals called carcinogens
- cause mutation in genes that control cell division which leads to cancer
what is drinking alcohol a risk factor of ?
- it is a risk factor for liver cirrhosis and liver cancer
- ethanol in alcohol broken down by enzymes in liver and toxic products produced damages liver cells
- detrimental as liver is important
lack of exercise
exercise helps maintain normal, healthy weight
- those who don’t get enough exercise are more likely to become overweight or obese
- also more likely to develop high BP and C.D
BMI
mass / (height) ²
how are you more likely to be obese and have a high BMI?
if you eat a high fat, high sugar diet and don’t do enough exercise, you are likely to take in more energy than you use.
why isn’t BMI always reliable?
athletes have lots of muscle which has a higher mass than fat
-an athlete could weigh a lot but not be at risk of CVD
waist to hip ratio
measures abdominal obesity which is closely linked to CVD
how is CVD caused?
- diseases of the heart/blood vessels are caused by the narrowing of coronary arteries
- it causes cells in the heart or brain to die due to lack of O2
how do coronary arteries narrow?
- when fatty deposits build up in the arteries, which occur in areas where the artery wall has been damaged
what are some lifestyle changes to reduce to risk/ treat CVD?
- healthy, balanced diet ( less salt and saturated fat )
- exercise regularly
- stop smoking
what are statins?
they lower the LDL cholesterol production by liver, less amount present in bloodstream
- effective at slowing down the formation of fatty deposits
cons of statins?
long term medication that MUST be taken regularly
effect of statins isn’t instant
side effects such as headaches
what are antihypertensives?
- reduce blood pressure
- effective at preventing damage to blood vessels and reduces risk of atherosclerosis
cons of antihypertensives
- side effects such as headaches and dizziness
what are anticoagulants?
- drugs that make blood clots less likely to form
- effective at reducing risk of blood clots which causes heart attacks and strokes
cons of anticoagulants?
- blood clotting is needed to prevent excessive bleeding
- increase risk of internal bleeding
what are stents?
- wire mesh tubes inserted inside arteries to widen them and keep them open
- it pushes fatty deposits back, making sure blood can pass through to heart muscles
advantages and disadvantages of stents
- effective for long time
- recovery time from surgery quick
- risk of infection from surgery
- risk of patient developing blood clot near stent
what is coronary bypass surgery?
a piece of healthy vessel is taken from elsewhere in the body and used to bypass a blocked section of the coronary arteries
advantages and disadvantages of
