Infection + diseases (part 2) P1 Flashcards
communicable vs non-communicable disease + health def
communicable = diseases which can be spread from person to person (infectious)
- spread by pathogens like bacteria and viruses (e.g measles)
non-communicable = diseases which cannot be passed from person to person
- biggest illness (e.g coronary heart disease, type 2 diabetes, most cancers)
health = the state of physical and mental wellbeing
How do diseases interact?
1) diseases can lead to ither diseases
e. g HPV can lead to cervical cancer
2) diseases can be triggered by the immune system
e. g asthma, body infected by a pathogen which immune system fights off, person left with an allergy
3) mental illness can be caused by a physical illness
e. g arthritis a person unable to move and live a normal life -> can make them feel isolated and depressed
Correlating risk factors (e.g lung cancer and cigaretts)
- causal mechanism ? / correlations
- epidemiology
a correlation does not prove cause ( e.g it simply suggests smoking can be LINKED to lung cancer)
Causal Mechanism : finding out if there are any scientific explanations to how something happens
e.g discovered that cigarett smoke contains chemicals which damage DNA and increases risk of cancer
carcinogens - something that increases the risk of cancer
epidemiology + PROBLEMS
studying patterns of diseases to determine risk factors
problems:
- sample size -> ungeneralisable as cannot sample everyone, can be culturally biased as some ppl in certain areas may exercise more , or are exposed to certain pollution in certain towns
- to avoid bias = take large sample as possible, random sample
Cardiovascular Diseases (what is it) + examples (NOT TREATMENTS)
= diseases of the heart and lungs
= non-communicable (not infectious)
1) Coronary heart disease
- when layers of fatty material build up inside the coronary artery causing them to narrow, reducing the blood flow meaning a lack of oxygen to muscles and heart
2) Faulty heart vales
- valves do not fully open so heart must pump harder than usual to get blood through, causes heart to enlarge
- leaky valves which causes weakness and fatigue
3) Heart failure
- heart cannot pump enough blood around the body
Treatments of Heart failure (2 types) cons
1) donated heart
cons:
not enough donors for each patient
patient must take drugs to stop the donated heart from being rejected by bodys immune system
2) artificial heart
cons:
only a temporary solution to allow heart to rest/ wait for a donor heart
increased risk of blood clotting
Treatments of Faulty heart valves (2 types) pros/cons
1) Mechanical valves pros: last a life time cons: increased risk of blood clot so have to take anticlotting drugs
2) Animal valves
pros:
no drugs needed to be taken
cons:
do not last as long
may need replacing
Treatments for coronary heart disease (2 types) pros/cons
1) statins (drugs) -> reduce the level of cholesterol in blood which slows down the rate that the fatty material can build up
pros:
effective - proven to reduce the risk of coronary heart disease
cons:
can cause liver problems
2) stent -> a tube which is inserted into coronary artery to keep it open so blood can flow normally
pros:
allows blood to flow normally
cons:
will not prevent other region or coronary artery from narrowing (does not treat the underlying causes)
carcinogens
something that increases the risk of cancer
Risk factors for cardiovascular diseases
- diet high in fat, low in veggies
= increases risk of cholesterol build up in blood ( fatty material build up)7 - diet high in salts
= increases blood pressure, increasing risk of developing cardio diseases
-smoking
Risk factors for lung disease/cancer
- smoking as cigarette smoke contains chemicals which can trigger cancer (carcinogens)
- radon (radioactive gas)
Effects of smoking/drinking on unborn babys
smoking:
- increased risk of miscarriage/ premature birth
- baby being born with a low body-mass
alcohol:
- fetal alcohol syndrome -> learning difficulties
Effects of drinking on adults
- increased risk of liver cancer
- effects brain -> addiction, loss of memory
Type 2 diabetes / link with obesity/alcohol?
Drinking a lot of alcohol can lead to obesity which can lead to type 2 diabetes ( struggle to control blood glucose levels)
four types of pathogens/ what is it/ how they are spread
viruses
bacteria
fungi
protist
pathogen: a microorganism that causes infectious disease
- air (e.g influenza)
- water (e.g cholera)
- direct contact (e.g HIV)
How do bacteria make us ill?
1) once inside the body, bacteria reproduce very rapidly
2) bacteria release harmful chemicals called toxins
3) toxins damage tissues and make us feel ill
How do viruses make us feel ill?
1) first, bacteria invades host cell
2) virus then reproduces inside host cell
3) this is very damaging to the cell, when the cell leaves it causes the cell to burst open and die (this is what makes us feel ill)
Reducing the spread of pathogens
1) washing your hands before eating
2) clean drinking water (UK water contains chlorine which kills microbes)
3) condom
4) self isolation (from really infectious diseases) as it prevents pathogen from spreading to other people via direct contact
5) vaccination
three viral infections
measles
HIV
TMV
= cannot be killed by antibiotics
Measles
-viral
symptoms: first is a fever, then after 3 days develop a red skin rash
-spread by droplets when an infected person coughs and sneezes, which is then passes onto another person through them inhaling droplets
can cause: damage to breathing system and brain
prevented: vaccinating children at a young age
HIV
viral
symptoms: flu-like symptoms
- spread through the exchange of human fluid through unprotected sex/druggies sharing infected needles as blood containing HIV can be passed from person to person via needle)
- the virus attacks the patients cells of their immune system
- overtime immune system becomes severely damaged which can lead to the immune system being unable to fight off infections which could easily be fought off before (could lead to cancer) -> can now contract other infections like TB
prevented (NOT A CURE) by taking antiretroviral drugs for the rest of their life (stops virus from multiplying inside patient so virus does not damage patients immune system)
= if taken does not lead to AIDS
two bacterial diseases
salmonella
gonorrhoea
= can be killed by antibiotics
Salmonella
- bacterial
symptoms: abdominal cramps, vomitting, diorrhoea, fever - spread by ingesting infected food by preparing in unhygienic conditions
- the bacteria secrete toxins
- found in poultry (chicken)
prevention : chickens in the UK are vaccinated to prevent the spread of disease
Gonorrohoea
- bacterial
- sexually transmitted disease
symptoms : thick yellow/green discharge from penis/vagina, pain when urinating
use to -> treat via penicillin
now -> treat using antibiotic resistant strains of bacteria
STOP spread by:
1) condom -> stops bacteria from passing to person to person
2) if having unprotected sex -> test for gonorrhoea, so can be treated with antibiotics to kill bacteria before passing it on
Malaria (life cycle/stop)
- protist
- caused by a parasitic protist(needs a host)
symptoms : repeated bouts of fever
-treatment : antimalarial drugs
Life cycle of malaria
1) person with malaria
2) mosquito bites them (a vector) so pathogen is now with mosquito
3) mosquito bites another person and passes pathogen onto them
STOP the spread:
1) stop vector from breeding (e.g mosquitos breed near still water, so drain it/spray it with insectiside)
= however impossible to kill all mosquitos
2) sleep under a mosquito net and spray it with insectiside -> prevents mosquito from biting and kills it with spray
Vector
An organism that carries pathogens without being infected
Non-specific defence system (4)
skin
= forms a protective layer covering body
- outer layer skin consists of dead cells -> difficult for pathogen to penetrate
- produces oily substance (sebum) -> kill bacteria
- scabs over if damaged
nose
- contains hair and mucus -> traps pathogens
trachea/bronchi
- covered in tiny hairs called cilia
- cilia covered in mucus -> traps pathogens
- cilia wafts mucus upwards which we swallow into stomach
stomach
-contains hydrochloric acids -> kills pathogens
2 mainfuntions of immune system
destroy pathogens and any toxins they produce
protects us incase same type of pathogen invades again
2 mainfuntions of immune system
destroy pathogens and any toxins they produce
protects us incase same type of pathogen invades again
How the immune system works (white blood cell)
1) Phagocytosis
- white blood cell detects chemicals released from pathogen and moves towards it
- wbc ingests pathogen
- wbc uses enzymes to destroy pathogen
2) Antibodies
-wbc releases antibodies
- wbc’s antibodies stick to pathogens which trigger pathogen to be destroyed
(specific, remain in body for long time to protect us against same pathogen)
3) Antitoxins
- wbc’s produce antitoxins
- antitoxins stick to toxin molecules and prevent them from damaging cells
antibodies
protein molecules produced by white blood cells
TMV (Tobacco mosaic virus)
viral infection in plants
causes: leaves to discolour in a mosaic patter, discolouration leads a decrease in the rate of photosynthesis which leads to plant growth being reduced
Rose black spot
fungi infection in plants
causes: leaves to develop purple/black spots, making the leaves turn yellow and fall off
= causes rate of photosynthesis to decrease and reduces growth
Spread by wind and water.
treating it:
1) fungicide (spray which contains chemicals to kill fungi)
2) remove infected leaves and destroy them
Vaccinations
1) inject via a needle, an inactive or dead version of a pathogen into body (cannot lead to disease)
2) white blood cells are stimulated to produce antibodies against dead/inactive pathogen
- at the same time white blood cell divides by mitosis to produce lots of chemicals of itself
3) these copies say in the body for a long time so if the same pathogen invades, they can quickly fight them off, preventing infection (memory cell)
memory cells
a cell capable of recognising foreign particles they were previously exposed to, being able to fight it off quicker
herd immunity
when enough of a population is vaccinated so it allows those who aren’t vaccinated to stay safe (90% of pop)
monocloanal antibodies
1) mouse injected with specific antigen
2) the mouses lymphocyte produces antibodies against antigen
3) collect lymphocytes from mouse
however lymphocyte does not divide by mitosis so must fuse with a tumour cell
4) fusion of lycmphocyte (correct antibodies, slow reproduction) with a tumour celll (reproduces rapidly but doesn’t have correct antibodies) = hybridoma cell
5) select a single hybridoma cell producing correct antibody -> allow it to divide by mitosis to form a clone of identical hybridoma cells (identical antibodies)
6) large amount of monocloanal antibodies are collected and purified
key ideas of monocloanal antibodies (specific, benefits)
- monocloanal antibodies produced by a single clone of hybridoma cells (means they are specific to one binding site and one protein antigen)
]BENEFIT -> MA can target a specific chemical/cell in body so have a large number of uses
Uses of monocloanal antibodies - pregnancy tests
POSITIVE TEST
1) Urine passes through reaction zone , where blue beads are covered in antibodies and are MOBILE. If HCG (pregnancy hormone) is present, it binds with the antibodies,
2) Urine washes the binded antibody and HCG up the strip, HCG binds to the immobilised HCG antibody in result zone.
3) Antibodies which do not attach to HCG bind to the antibodies in the control zone
4) Blue dye appears in both control and results zone
NEGATIVE TEST
1) Urine passes through reaction, no HCG present so does not bind to antibodies.
2) Mobalised antibodies washed up the strip past the immobalised antibodies and DO NOT BIND
3) Binds to the antibodies in the control zone only
Uses of monocloanal antibodies - identifying chemical in the blood
- since ma are specific to one antigen, they can be designed to identify specific chemical in blood
1) identify level of hormones in blood
2) detect pathogens in blood
3) identify specific molecules in a tissue or cell by binding them to fluorescent dye, areas in body with a lot of these molecules can be highlighted by the dye
Uses of moncloanal antibodies - treating diseases
e.g cancer cells which undergo uncontrolled mitosis and spread around the body
- scientists use ma to make specific antibodies to cancer cells
- attach a radioactive substance/ toxic drug to antibody
- antibody injected into blood -> attaches to cancer cell
= effective as antibody delivers the substance specifically to cancer cell without harming any other cells in the body
Problems:
- harmful side effects
