B5 - health and disease Flashcards
define ‘health’
a state of complete physical, mental and social well-being, and not merely the absence of disease
define ‘disease’
an abnormal condition that causes part of an organism not to function properly
what are the 2 types of disease
communicable
non-communicable
what is a communicable disease
diseases that can be spread between individuals, caused by pathogens
what is a non-communicable disease
diseases that cannot be transmitted between individuals
examples of communicable disease
- cholera
- tubercolosis
- malaria
- chalara dieback
- HIV
examples of non-communicable disease
- cancer
- diabetes
- cardiovascular disease
what is a pathogen
a micro-organism that causes disease
examples of pathogens
bacteria, virus, protist, fungi
what is a toxin
a harmful chemical produced by a microorganism
what pathogen causes cholera + symptoms + how it spreads
bacterium
- diarrhoea
- contaminated water supplies
what pathogen causes tuberculosis + symptoms + how it spreads
bacterium
- coughing, lung damage and fever
- through the air when infected people cough/ sneeze/ breathe
what pathogen causes malaria+ symptoms + how it spreads
protist
- damage to RBC and (extreme) liver
- mosquitos
what pathogen causes chalara dieback + symptoms + how it spreads
fungus
- lesions on branches, dead leaves and branches
- through the air by the wind, when disease trees move between areas
what is the host of chalara dieback
ash trees
how to reduce the spread of cholera
ensure people have access to clean water supplies
how to reduce the spread of tuberculosis
infected people should avaoid public places, practice good hygine, sleep alone in a well ventilated room
how to reduce the spread of malaria
use mosquito nets and inscet repellent to prevent being bitten by mosquitos carrying the disease
how to reduce the spread of chalara dieback
remove infected ash trees, replant with a different species
restrict the import/ movement of ash trees
what is a vector, give eg.
organisms that carry a disease and transmit it between organisms
eg. mosquitos transmit malaria
what is non-specific defence
features of the body that’ll fight any type of pathogen that they come across, not specific to a particular type of disease
what are the 2 types of non-specific defense
physical and chemical barriers
examples of physical barriers
- skin: barrier to pathogens, if cut blood quickly clots to seal microorganisms out
- hair and mucus in nose: trap particles that may contain pathogens
- cells in airways/lungs: produce mucus to trap pathogens, have cilia to waft mucus back up throat to be swallowed
examples of chemical barriers
- stomach acid: contains hydrochloric acid which kills most swallowed pathogens
- lysozyme: produced by eyes in tears, killls any bacteria on the surface of the eye
what are STIs, give eg
infections that are spread through sexual contact eg. sexual intercourse
- eg. HIV and Chlamydia
what do viruses have to do in order to reproduce
infect living cells (host cells)
- specific viruses only infect specific cells
what does HIV stand for
human immunodeficiency virus
what does HIV do
- infects and kills white blood cells, weakening the immune system
- eventually leads to AIDS
- causing the infected person’s immune system to deteriorate and eventually fail
- they become vulnerable to opportunistic infections from other pathogens
how is HIV spread
through the transmission of infected bodily fluids eg. blood, semen, vaginal fluids
ways to reduce the spread of HIV
- use a condom in intercourse
- drug users avoid sharing needles
- medication so infected people are less likely to pass virus on to others eg. during intercourse/ pregnant woman onto her baby
what is chlamydia
- a bacterium that behaves similarly to a virus as it can only reproduce inside host cells
- doesn’t always cause symptoms, but can lead to infertility in men and women
ways to reduce the spread of chlamydia
- use a condom in intercouse
- regular screening so people can be treated for the infection
- avoid sexual contact
what happens if a pathogen makes it inside the body
the immune system protects the body by attacking the pathogens
what is an antigen
a molecule on the outside of a pathogent that triggers an immune response
how does the immune system attack a pathogen
- a pathogen with an antigen on the surface enters the body
- antigen is detected
- lymphocytes produce antibodies that fit specifically to the antigen
- WBC produces many antibodies that flow around body killing all similar pathogens
what is the response like when a pathogen enters the body for the first time, why
slow, because there aren’t many b-lymphocytes that can make the antibody needed to lock on to the antigen
how does the body overcome an infection the first time
after a while the body produces enough of the right antibody to overcome the infection, meanwhile the infected person will show symptoms of the disease
what is produced as well as antibodies in response to a foreign antigen
memory lymphocytes
what are memory lymphocytes
lymphocytes that remain in the body for a long time and ‘remember’ how the antibodies for a specific antigen were made
what happens if the same pathogen enters the body again
Memory lymphocytes recognise the antigen and produce antibodies to destroy it much faster
what is the secondary immune response against a pathogen like
faster and stronger than the first time, it often gets rid of a pathogen before symptoms begin to show
what can you do to avoid getting ill (vaccine)
you can be immunised eg. measles
what does immunisation involve
- injecting dead or inactive, antigenic pathogens into the body
- even though they’re harmless the body produces antibodies to help destroy them
what does antigenic mean
they carry antigens
how does immunisation help in the long term
- the antigens also cause the production memory lymphocytes
- if live pathogens of the same type enter the body, the memory lymphocytes will cause the secondary immune response
what is herd immunity
when enough people have immunity to a pathogen so that infection is much less likely to occur and spread
how do antibiotics work
Kill bacteria by inhibiting processes in bacterial cells but not in the host organism
eg. some prevent the build up of bacterial cell walls preventing bacteria from dividing, doesn’t affect host as human cells don’t have cell walls
drawbacks of antibiotics, why
- don’t destroy viruses
- viruses reproduce inside body cells, this makes it difficult to develop drugs that destroy the virus without destroying the host’s body cells
define antibiotic
medicines that inhibit cell processes in bacteria
what are the 2 stages of testing
preclinical
clinical
what is the first stage of preclinical testing
lab testing on human cells or tissues, checks the safety and toxicity
limitations of testing on human cells and tissues
- can’t be used to test drugs that affect the whole or multiple body systems
- eg. blood pressure drugs must be tested on the whole animal
what is the second stage of preclinical testing
testing on live animals
- tests how the drug work, toxicity, dosage on a whole organism
first stage of clinical trials
- tested on heathy volunteers
- to ensure there are no harmful side effects when the body is working normally
second stage of clinical testing
- testing on people with the illness
- finds the optimum dose: most effective, and fewest side effects
how are clinical trials undertaken
- patients put randomly in 2 groups
- one group given the new drug, other given a placebo
how are placebo trials done
- blind
- the patient doesn’t know whether they’re getting real or placebo
- often double blind
- the doctor also doesn’t know
why do the doctors often not know in placebo trials
- so the doctors monitoring the patients and analysing patients aren’t influenced by their knowledge
what is the final stage of clinical trials
final testing and licensing
- large scale
- still has to be monitored
what happens once a drug passes all the tests
needs to be approved by a medical agency
what are non-communicable diseases caused by
they’re not caused by pathogens
- there are risk factors that can increase the likelihood that a person will develop a disease
what are the 2 types of risk factor
- unavoidable: age, gender
- lifestyle factors: smoking, alcohol consumption
define malnutrition
a disease caused by a diet with too many or too few nutrients
what is the link between alcohol and liver disease
drinking a large amount of alcohol causes cirrhosis (scarring of the liver) as alcohol is broken down by enzymes in the liver, and some products are toxic
if over a long time, can cause permanent liver damage
the effects of alcohol consumption on liver disease at local levels
- areas with high alc consumption increases risk of liver disease which puts a strain on local hospital resources
the effects of alcohol consumption on liver disease at national levels
- costly for the NHS that provides resources for treatment all over the UK
- people suffering from non-communicable disease may not be able to work, can affect the economy
the effects of alcohol consumption on liver disease at global levels
- high cost and occurrence of a disease can hold back the development of a country
how to measure bmi
mass/height^2
what bmi is considered overweight and obese
overweight - over 25
obese - over 30
how to calculate waist to hip ratio
waist circ/ hip circ
what does waist to hip ratio indicate, what measure is overweight
how much fat is stored around the abdomen
females - 0.85
males - 1.0
how does smoking correlate with CVD
- nicotine: increases HR and BP
- high BP: damages artery walls which causes build up of fatty deposits which restrict blood flow and inc risk of heart attack or stroke
- smoking: inc risk of blood clots in arteries limiting blood flow, inc risk of heart attack or stroke
how do fatty deposits in arteries increase risk of heart attack or stroke
- trigger blood clots which can block blood flow (completely)
- in an artery supplying heart muscle = no oxygen to heart = heart attack
- block to brain = brain has no O2 = stroke
what lifestyle changes are used to treat CVD
- balanced diet low in sat fats
- regular exercise
- weight loss (if ness)
- quit smoking (if ness)
recommend before other treatments as there don’t tend to be downsides
what medicines (drugs) are used to treat CVD
- statins: reduce cholesterol in blood
- anticoagulants: make blood clots less likely to form
- antihypertensives: decrease blood pressure prevent damage to blood vessels
negatives of drugs used to treat CVD
- statins: aching muscles, sometimes liver damage
- anticoagulants: can cause excessive bleeding
- antihypertensives: headaches and fainting
what surgical procedures are used to treat CVD
- stents: tubes inserted inside arteries to ensure blood can pass through to heart
- coronary bypass surgery: healthy, piece of vessel to bypass a blocked one
- donor hearts: replace whole heart
negatives of surgical procedures used to treat CVD
- stents: irritate artery causing to narrow again
- donor heart: drugs taken so body doesn’t go into rejection can inc risk of infection
risks of heart surgery
bleeding
clots
infection
