Topic 5: Health & Disease Flashcards
What is health?
A state of complete physical, mental and social well being, and not merely the absence of disease or infirmity
What can cause ill health?
Diseases
What can having a disease do to your body?
Can weaken your body - makes you more susceptible to other diseases
What are the two types of diseases?
Communicable diseases
Non-communicable diseases
What are communicable diseases?
A disease that can spread from person to person or between animals and people
What are non-communicable diseases?
A disease that cannot spread between people or between animals and people
What are properties of viruses?
They aren’t cells
They infect living cells to reproduce
What are the two pathways a virus can take when it enters an organism?
Lysogenic pathway
Lytic pathway
What happens in the lysogenic pathway?
- The virus inserts its DNA into the host cell and the DNA becomes incorporated into the host DNA
- As the host cell replicates, the viral DNA also replicates
- Changes in the environment can cause the viral DNA to move to the lytic pathway to make new virus particles
What happens in the lytic pathway?
- The virus infects the host cell and injects its DNA into the cytoplasm
- The virus uses proteins and enzymes within the host cell to produce new virus particles
- The host cell then bursts, this releases the virus particles into the host organism
- More cells are infected by the virus particles
What is a pathogen?
An organism that causes a communicable disease
What pathogen causes chalara ash dieback?
Fungus
How is chalara ash dieback spread?
Wind and air
Transfer of disease trees
What are the symptoms of chalara ash dieback?
Leaf loss
Bark lesions (wounds)
How can spread of chalara ash dieback be reduced?
Remove & dispose of infected ash trees
Restrict imports
What pathogen is malaria caused by?
Protist - plasmodium
How is malaria spread?
Mosquito vectors
What are the symptoms of malaria?
Damage to red blood cells
Damage to liver
Fever
Headaches
How can spread of malaria be reduced?
Mosquito nets
Insect repellents
Anti malarial tablets
What pathogen is cholera caused by?
Bacterium
How is cholera spread?
Contaminated water sources
What are the symptoms of cholera?
Diarrhoea
Stomach cramps
How to reduce spread of cholera?
Vaccine
Drink and use clean water
What pathogen is tuberculosis (TB) caused by?
Bacterium
How is tuberculosis spread?
Airborne droplets (coughs and sneezes)
What are the symptoms of tuberculosis?
Coughing
Lung damage
Fever
How to reduce spread of tuberculosis?
Vaccine
Stay away from infected people
Anti biotics
What pathogen are stomach ulcers caused by?
Bacterium
How are stomach ulcers spread?
Oral transmissions e.g. saliva
What are symptoms of stomach ulcers?
Stomach pain
Nausea
Vomiting
How can the spread of stomach ulcers be prevented?
Have clean water supplies
Antibiotics
Hygienic living conditions
What pathogen is Ebola caused by?
Virus
How is Ebola spread?
Bodily fluids e.g. blood
What are symptoms of Ebola?
Fever
Internal bleeding
Muscle pain and weakness
How can spread of Ebola be reduced?
Isolated infected individuals
Sterilise areas
BUT NO TREATMENT
What is a sexually transmitted disease?
Infection spread through sexual contact
What pathogen is chlamydia caused by?
Bacterium
How is chlamydia spread?
Sexual contact and sexual bodily fluids
What are the symptoms of chlamydia?
No symptoms
Pain when urinating
Can lead to infertility
How can the spread of chlamydia be reduced?
Wear a condom
Avoid sexual contact
Antibiotics
What pathogen is HIV caused by?
Virus
How is HIV spread?
Bodily fluids
What are symptoms of HIV?
Reduces immune response/damages immune system
Flu like illness is developed 2-6 weeks after infection
How to reduce the spread of HIV?
Wear a condom
Take medication
Avoid sharing needles
What are the two types of human defences against disease?
- Physical barriers
- Chemical barriers
What are the different types of physical barriers against disease in humans?
Skin - thick and covers whole body - acts as a barrier to pathogens
Hairs and mucus in nose - traps particles containing pathogens
Cilia in the respiratory system - move mucus across the ciliated cells which therefore gets rid of pathogens and sends them to the throat
What the types of chemical barriers against disease in humans?
Hydrochloric acid in the stomach - kills pathogens
Lysozymes in tears - enzyme that kills bacteria secreted by skin
What is specific immune response?
The immune response to a specific pathogen
What is the process of the specific immune response?
- New pathogen in the body which has unique antigens
- The antigens trigger antibodies specific to the pathogen be produced by the B-lymphocyte
- The antibodies attack all copies of the pathogen in the body
What is secondary immune response caused by?
When memory lymphocytes trigger a fast production of antibodies - the response is faster and quicker
Why is the secondary immune response faster?
The memory lymphocytes already know how to produce antibodies in the body to a specific pathogen IF it’s already been in the body
What is immunisation?
A process that makes an individual resistant to becoming ill from a specific communicable disease
What does a phagocyte do?
Engulfs and destroys pathogen - phagocytosis
What does a lymphocyte do?
Produce antibodies
What is a vaccination?
A dead or weak form of the pathogen
How do vaccines work?
- A dead or inactive pathogen is injected into the body
- The b lymphocytes produce antibodies and memory lymphocytes that remain in the blood stream for a long period of time
What is the effect of vaccines? Why?
- When live pathogens get past the bodies natural defence systems, the memory lymphocytes recognise them
- The memory lymphocytes then produce antibodies quickly
- This means that the person isn’t affected by the pathogen and doesn’t get ill
BECAUSE VACCINES MAKE YOU IMMUNE TO DISEASES
What are advantages of immunisation?
Prevents individuals getting ill
Can create herd immunity
Has almost wiped out some disease e.g. smallpox was eradicated
Disadvantages of immunisation?
Doesn’t always work
Some people have bad reactions to vaccines
What is herd immunity?
Where a high percentage of the population is immunised so the spread of disease is limited, meaning large outbreaks of diseases are unlikely
What the types of physical barriers against disease in plants?
Waxy cuticle on leaves - barrier to pests and pathogens and are impermeable
Cellulose cell walls - barrier to pathogens and pests around cells
Bark
What the types of chemical barriers against disease in plants?
Antiseptic chemicals - kill bacterial and fungal pathogens e.g. witch hazel
Some plants produce bitter chemicals and poisons to deter pests from feeding on them
What are the 4 ways to identify plant diseases?
- Observation - look at a plants symptoms and identify the disease
- Experimentation - alter plants environmental conditions and observe changes
- Analysing distribution - identify the disease by looking at distribution of affected plants
- Diagnostic testing - test sample of plant tissue in lab for the presence of a particular pathogen
What are the two examples of diagnostic testing in plants?
- Use monoclonal antibodies to detect antigens from the pathogen
- Test for the pathogens DNA
What are monoclonal antibodies?
Antibodies made by identical immune cells, these identical immune cells are clones of the parent cell
What’s the process of producing monoclonal antibodies?
- Mouse injected with the chosen antigen
- B-lymphocytes from the mouse are simulated (these make antibodies but don’t divide easily)
- The lymphocytes are combined with a tumour cell to make a hybridoma cell
- The hybridoma cell divides quickly and produces lots of clones that produce monoclonal antibodies
What are the 3 uses of monoclonal antibodies?
- Pregnancy tests
- Treating cancer
- Detecting cancer cells and blood clots
What is the zone of inhibition?
A method to compare effectiveness of an antibiotic
How do pregnancy tests work (monoclonal antibodies)?
- Once a woman becomes pregnant the embryo will secrete the hormone hCG which is in the urine
- Pregnancy tests are made with specific monoclonal antibodies that will only bind to hCG
- The female taking the test will urinate on the test strip, the hCG in the urine will attach to a mobile monoclonal antibody with a coloured bead attached to it
- The hCG antibody complex moves along the test with the urine until it reaches an immobile antibody test strip. hCG binds to these antibodies which causes the line to show up a colour
How do monoclonal antibodies treat cancer?
- The monoclonal antibody which is specific to a tumour marker attaches with an anti cancer drug
- The monoclonal antibody binds to tumour markers (which are unique to cancer cells)
- The substance in the anti cancer drug is delivered to the cancer cell
- The other body cells remain unharmed
What are advantages of using monoclonal antibodies to treat cancer?
Don’t damage other cells in the body
What are disadvantages of using other treatment methods (not monoclonal antibodies) e.g. radiotherapy to treat cancer?
Radiotherapy and other methods can lead to a damage to normal body cells
How can monoclonal antibodies be used to detect cancer cells and blood clots?
- Radioactive element is attached to a monoclonal antibody
- This binds to a tumour marker or a protein in a blood clot
- The location of the radioactivity can be found with a special camera to locate the blood clot
What do antibiotics kill? How?
Only bacteria
They inhibit processes in bacterial cells BUT NOT in the host organism
What are the important things to consider when drug testing?
Efficacy - how well the drug works
Toxicity - how harmful the drug is and side effects
Dosage - how much of the drug should be taken for it to be effective
What is the process of drug testing?
- Pre clinical testing
- Animal testing
- Clinical testing
- Large clinical
What is done in the preclinical testing stage of drug development?
The drugs are tested on humans cells and tissues
What are advantages of pre clinical testing?
Easy and cheap
Disadvantages of preclinical testing?
Doesn’t show what side effects there could be
What is done in the animal testing stage of drug development?
The drug is tested on live animals e.g. mammals
What are the issues surrounding animal testing?
Many are against it - ethical issues
What is done in the clinical testing stage of drug development?
The drug is tested on healthy volunteers
The dosage gradually increases from a very low initial dose
What is done in the large clinical testing stage of drug development?
The drug is given to ill patients
This is so that the optimum dosage can be found
How do the scientists ensure the drug testing process is fair?
The clinical trails are often double blind - half of the testers are given drug, half are given a placebo and the scientists don’t know who has what
What is a placebo?
A substance that is similar to the one being tested but don’t do anything
How do antibiotics kill bacteria?
Stop their cellular processes but don’t damage host cells
What is a risk factor?
Things that are linked to an increase in the likelihood that a person will develop a certain disease during their lifetime
What are the 4 risk factors for non communicable diseases?
- Lack of exercise - linked to cardiovascular disease and obesity
- Poor diet - may have too many or too few nutrients can lead to malnutrition, obesity or scurvy
- Drinking too much alcohol - can cause liver disease and cardiovascular disease
- Smoking - can cause cardiovascular disease, lung disease and lung cancer
What is scurvy caused by?
A lack of vitamin c
What are the 3 types of effects of non communicable diseases?
- Local
- National
- Global
What is the local effect of non communicable diseases?
High levels of disease puts pressure on local hospitals
Pressure on family
Unemployment
What is the national effect of non communicable diseases?
Expensive for NHS to treat everyone
Reduces number of people who can work - affects economy
What is the global effect of non communicable diseases?
Costs associated with high levels of disease - can hold back a countries development
What are the two measures to calculate obesity?
- BMI
- Waist to hip ratio
How to calculate BMI?
BMI = mass/height^2
How to calculate waist to hip ratio?
Waist to hip ratio = waist circumference/hip circumference
What does the waist to hip ratio have to be in men for them to be considered obese?
Anything above 1.0
What does the waist to hip ratio have to be in women for them to be considered obese?
Anything above 0.85
What does a waist to hip ratio indicated (area)?
Abdominal obesity
What does a gastric sleeve do?
Limits the amount of food you can eat by making you feel full after eating small amounts of food
What is a cardiovascular disease?
Any disease associated with the heart and blood vessels
What happens in the body when someone has a cardiovascular disease? What can this lead to?
- Their coronary artery gets blocked by the build up of fat by increase LDL cholesterol - gets narrower
- Less blood can flow through it to get to the heart - puts strain on the heart
- The person is thus more likely to have a blood clot or blocked vessel
- May lead to a heart attack or stroke
What is a stent? What does it do?
A tube placed in the artery to hold them open
Ensures that blood keeps flowing
What are the 4 main treatments for cardiovascular disease?
- Lifestyle changes
- Statins
- Stents
- Heart transplant
What is a statin?
A medicine that alters the balance of cholesterol in the blood
Decreases LDL cholesterol (bad) & increase HDL cholesterol (good)
What does LDL cholesterol do?
Increases fat build up in the arteries
What’s does HDL cholesterol do?
Gets rid of fat from arteries
What are examples of lifestyle changes?
Stopping smoking
Reducing alcohol intake
Eating a balanced diet
Regular exercise
What are advantages of lifestyle changes?
Reduces risk of heart attacks and strokes
What are disadvantages of lifestyle changes?
None
What are advantages of statins?
Reduces LDL cholesterol
Lowers risk of cardiovascular disease e.g. coronary heart disease
What are disadvantages of statins?
Have side effects e.g. possible liver damage , type 2 diabetes etc.
Must be taken regularly
What are advantages of stents?
Keeps arteries open so blood flow isn’t blocked
Effective for a long time
Doesn’t involve surgery
What are disadvantages of stents?
Scar tissue may form
Have to take drugs so blood doesn’t clot
Can increase risk of heart attacks
What are advantages of heart transplants?
Can treat heart failure
Treat cardiovascular disease when no other treatments work
What are disadvantages of heart transplants?
There are risks from surgery
Immunosuppressants must be taken for the rest of their life after surgery - weaken immune system & increase risk of infection
Shortage of donors - waiting list is long
ANTIBIOTICS CORE PRACTICAL: What are the steps taken to prepare an aseptic culture of bacteria in the lab?
- Hot agar jelly is poured into the Petri dish and allowed to cool and set
- An inoculating loop is passed through a hot flame to sterilise it - loop is used to transfer bacteria to the agar jelly
- The Petri dish always has a lid on - stops any microorganisms in the air from getting in, it is stored at 25°C and also upside down to stop drops of concentration falling on the agar surface
ANTIBIOTICS CORE PRACTICAL: What is the process of testing effectiveness of antibiotics on bacteria?
- Prepared agar plate is evenly covered in bacteria
- Then place 3 filter discs that are soaked in 3 different types of antibiotics, into 3/4 of the jelly, use the last quarter as a control
- Leave the bacteria for a couple of days in an incubator
- Then measure the zone of inhibition (the area where no bacteria has grown) by measuring the diameter of the zone - to work out the area of the zone of inhibition use πr²
ANTIBIOTICS CORE PRACTICAL: What are the independent and dependent variables in this experiment?
Independent: type of antibiotic
Dependent: width of the inhibition zone
ANTIBIOTICS CORE PRACTICAL: What is the conclusion of this experiment?
The wider the zone of inhibition, the more effective the antibiotic
What does HIV lead to?
AIDS
How does HIV damage the immune system?
Destroys white blood cells and weakens them
