Topic 5: Health, Disease and the Development of Medicine Flashcards
What is health?
A state of complete physical, mental and social well-being
What is disease?
A disorder of the body or mind that negatively affects an individuals health
What are the two types of disease?
Communicable and non-communicable
What is a communicable disease?
A disease that is passed directly between individuals and caused by a pathogen
What is a pathogen?
A disease-causing organism
What is a non-communicable disease?
A disease that cannot be transmitted between individuals, caused by lifestyle, environmental conditions and genetic mutations
What is a symptom?
A change experienced by an organism that indicates disease
Why does having an illness make an individual more likely to contract another disease?
A disease may weaken an individuals immune system making them increasingly susceptible to other infections
What is cholera?
Caused by bacteria, spread by drinking water or washing in water that had been contaminated with infectious faeces and the symptoms are diarrhoea and vomiting
How can the incidence of cholera be reduced?
Access to clean water and improved sanitation
What is tuberculosis?
Caused by bacteria, it’s an airborne bacteria spread by droplets infection and the symptoms are lung damage, chesty cough and wheezing
How can the transmission of TB be reduced?
Improved hygiene, infected individuals should avoid crowed area and increased ventilation in the individuals home
What is chalara ash dieback?
Caused by a fungus, spread via airborne and causes dark lesions on bark and blackened leaves which wilt and eventually die
How can the transmission of Chalara ash dieback disease be reduced?
Control the movement of ash trees, kill infected plants and replant with a different species
What is malaria?
Caused by protist, spread by mosquito vector and flu-like symptoms, damage to red blood cells and liver damage
How can the incidence of malaria be reduced?
Mosquito nets, insect repellent and cover arms and legs
What is stomach ulcers?
Caused by bacteria, transmitted orally by eating infected food or drinking infected water and symptoms are stomach pain, vomiting and nausea
How can the transmission of Helicobacter pylori be reduced?
Access to clean water, improved hygiene and improved sanitation
What is Ebola?
Caused by virus, spread by direct contact with infected bodily fluids and symptoms are fever, diarrhoea, vomit ting and internal bleeding
How can the transmission of Ebola be reduced?
Improved hygiene, isolating infected individuals and sterilisations of outbreaks areas
How can viruses cause disease?
They enter host cells and replicate inside of them, the host cells rupture, releasing new viruses
How do viruses differ from other microorganisms?
Viruses are not living organisms, they don’t reproduce and can only replicate inside a host cell
By what two pathways do viruses replicate inside living cells?
Lytic and Lysogenic pathway
What happen in lytic pathway?
Virus binds to specific receptors on host cell, virus injects it’s DNA into host cell and replicates it’s DNA using host cell machinery, new viral structures are produced and assembled then the host cell ruptures releasing new viruses
What happens in lysogenic pathway?
Virus binds to specific receptors on host cell, viral DNA injected into host cell and becomes integrated into host cell genome, viral DNA replicates each time the host cell divides, however, the cell remains normal and this triggers a cause the activation of viral DNA, it enters lytic pathway
What is HIV?
Caused by virus, spread by direct contact with infected body fluids and destroys white blood cells making the individual immunodeficient and increasingly susceptible to other diseases (leads to AIDS)
How can the spread of HIV be reduced?
Use of condom and protected sex, needle exchange, screening blood for HIV and deterring infected mothers from breastfeeding
What is chlamydia?
Cause by bacteria, spread through sexual/direct contact with infected genital fluids and can result in infertility
How can the transmission of Chlamydia be reduced?
condoms, protective sex and screening
What are some examples of non-communicable diseases?
Cancer, diabetes, cardiovascular diseases and chronic respiratory diseases
What is a risk factor?
A variable associated with a greater chance of developing a disease or infection
What factors that can affect the risk of developing a non-communicable disease?
Lifestyle, environmental factors and genetics
what does ‘correlation doesn’t mean causation’ mean?
Correlation between a risk factor and a disease doesn’t mean that the risk factor causes the disease, other factors may be involved and some may be linked
How does exercise affect the risk of some non-communicable diseases?
Regular exercise decreases fat stored reducing obesity and it decreases heart rate recovery time and blood pressure lowering the risk of CVD
How can diet affect the risk of some non-communicable disease?
Diet high in saturated fat raises blood cholesterol levels, increasing the deposition of fatty deposits in the arteries so greater risk of CVD, obesity and the consumption of large armoury’s of simple-sugars increases the risk of type 2 diabetes and malnourishment increases the risk of deficiency diseases
What is the body mass index?
A value based on height and mass used to categorise an individual as underweight, normal weight, overweight or obses
How is BMI calculated?
Mass / (height)2
Why isn’t BMI always an accurate measure of obesity?
Fate and muscle tissue cannot be distinguished so athletes may be incorrectly categorised as obese
How is an individual waist-to-hip ratio calculated?
Waist circumference / hip circumference
How does alcohol affect the risk of some non-communicable diseases?
Alcohol broken down into toxic products in the liver which build-up and cause cirrhosis, alcohol raises blood pressure this increasing the risk of CVD and toxic products in alcohols can cause mutations to DNA, increasing the risk of cancer
How does smoking affect the risk of some non-communicable diseases?
Raises heart rate, increasing the risk of CVD, lowered the ability of red blood cells to carry oxygen so heart rate increases causing higher risk of CVD and smoking increases the risk of lung diseases
How do environmental factors affect the risk of some non-communicable diseases?
Long-term exposure to pollution damages the airways, increasing the risk of lung diseases and cancer, exposure to UV radiation damages DNA causes skin cancer
How do genetics affect the risk of some non-communicable diseases?
The risks of some diseases are increased if a family member has had these conditions and faulty genes can be inherited which increase the risk of conditions
How do diseases interact with each other?
Some disease may cause other infections to develop and some diseases reduce the risk of contracting other infections
What are the effects of non-communicable disease on a local, national and global level?
Increased incidence of non-communicable disease puts a strain on local hospitals, increased pressure of NHS to provide treatment to a larger number of patients (effects the country’s economy) and high prevalence of malnutrition in LEDCs slows the development which turns impacts global development
What is cardiovascular disease?
Group of disease affecting the heart or blood vessels, build up of fatty deposits on the walls of the arteries forms atheromas which reduce blood flow toy muscle tissue and blood clots may form blocking the arteries and stopping blood flow completely this may lead to heart attack or stroke
How can CVD lead to a heart attack?
Obstruction of the coronary artery due to an atheroma or blood clot, results in loss of blood supply to an area of heart muscle and this causes death to the cells and leads to a heart attack
How can CVD be treated?
Improving diet and lifestyle, medication and surgery
Has changes to diet and lifestyle can be made to reduce the risk of CVD?
Regular exercise, reduce intake of saturated fat, maintenance of a healthy weight, diet low in salt, reduce stress and stop smoking and drinking alcohol
How effective are changes to lifestyle and diet in treating CVD?
Although not themselves effective in the treatment of CVD, they can enhance the efficiency of other methods of treatment
Which medicines are used to treat CVD?
Statins, Anticoagulant and Antihypertensives
What are the benefits and risks of using statins to treat CVD?
Statins lower the level of cholesterol in the blood however they can cause liver damage, kidney failure or problems with memory
What are the benefits and risks of using anticoagulants to treat CVD?
Anticoagulants reduce blood clotting, lowering the risk of a heart attack or stroke however they can cause excessive bleeding
What are the benefits and risks of using antihypertensives to treat CVD?
Lower blood pressure, reducing damage to artery walls and the build up of atheromas however they can have unpleasant side-effects such as headaches or fainting
What are stents?
Small, hollow tubes inserted into the lumen of arteries to keep them open and require surgery to insert
What are the problems with the use of stents to treat CVD?
Stents cause the growth of scar tissue in the arteries over time, further narrowing the lumen and blood clots may stick to stents
What is a coronary bypass?
Using a blood vessel from another region of the body to divert blood around a blockage into the coronary artery
What does a heart transplant involve?
Replacing a damaging heart with a donated heart and immunosuppressant drugs taken to prevent organ rejection
What are the benefits of heart surgery?
Lifesaving and can provide a permanent solution to a disease
What are the risks of heart surgery?
Involves many risks, difficult to find donors, risk of rejection, expensive and long recovery time
What are the physical defence system within plants?
Waterproof waxy cuticle which is a surface barrier preventing the entry of pathogen and cellulose cell wall which further is a barrier against pathogens
What are some examples of chemical barriers in plants?
Secretion of toxins to reduce damage by pests and production of antibacterial chemicals that kill bacterial pathogens
How are chemicals produced by plants useful?
They produce physiological effects on the body so can be used in medicines to treat diseases
What are examples of medicine derived from plants?
Quinine and Aspirin
Why are plant defence systems important?
Plants are producers so all organisms higher up in food chains rely upon their survival and ability to fight disease and it’s important in maintaining human food security
How can plant diseases be detected and identified in the field?
Observation of symptoms, analysis of the distribution of infection plants can indicate the type of pathogen involved and it’s mode of transmission and changing environmental conditions to elimaye other causes
Why is it difficult to identify a disease using symptoms alone?
Many diseases may have similar symptoms
How can plant diseases be detected and identified in the lab?
Detection of foreign antigens in a sample of plant tissue using monoclonal antibodies and analysis of DNA to identify any pathogen DNA in a tissue
What is a non-specific defence?
Always present, same for all organisms and prevents pathogens from entering the body
What are the physical defence system within the body?
Skin as a protective surface barrier, blood clotting as platelets seal wounds preventing entry of pathogens into the blood and respiratory tract as mucus traps pathogens, cilia waft mucus to the back of the throat where it’s swallowed
What are the chemical defence system within body?
Tears as contains lysozyme which digests bacterial cell walls, killing bacteria and protecting the eyes and hydrochloric acid in the stomach as acidic pH kills pathogens that are swallowed
What is the immune system?
The body’s defence against pathogens once they had be entered the body and aims to prevent or minimise disease caused by pathogens
How do white blood cells detect pathogens on the body?
Pathogens have unique antigens on their surface which are detected by specialised receptors on white blood cells
How does the immune system destroy pathogens?
B-lymphocytes produce antibodies in response to a particular antigen, each antibody is specific to an antigen and binds to it and antibodies ‘tag’ pathogens or clump them together, disabling them do that they can be killing by other WBCs
What are memory lymphocytes?
WBCs produced in response to a foreign antigen that remain in the body after a pathogen has been destroyed and provide immunity
Compare the primary and secondary immune response
The secondary response produces antibodies more rapidly and in highly concentrations that in the primary response. The pathogens is destroyed before it cause cause symptom
What is a vaccinated?
Deliberate exposure of an individual to foreign antigens, triggers an immune response and provides immunity and the individual doesn’t contract the disease that they are being immunised against
What are the components of a vaccine?
Dead, weakened or inactivated pathogens with their surface antigens still present
What are the benefits of vaccination?
Herd immunity - vaccination of a significant proportion of the population gives some protection to individuals who are not immune and helps to prevent epidemics and pandemics
What are the drawbacks of vaccination?
High mutation rate, not guaranteed to work, vaccination programmes are costly, may cause an adverse reaction and inactive pathogens may mutation and become pathogenic
What is an antibiotic?
A substance that kills or inhibits the growth of bacteria, no effect on cells in the host organism and produced by living organisms
How do ‘target’ molecules for new medicines be identified?
Comparisons of the genomes of unaffected individuals and those who are affected by a disease to identify potential disease-causing alleles and the alleles themselves or the proteins that they code for can be used as a target
What are the stages of drug development?
Screening for potential drugs, preclinical trials, clinical trials and approval by a medical agaency
What happens the process of screening?
Uses a machine to test large libraries of chemical substances, enables identification of pre-existing chemicals which may affect the target molecule and chemicals may be altered, allowing scientists to produce a drug that reacts with target molecules in a specific way
What do preclinical trials involve?
Drug testes on cultured human cells and using computer models to determine its toxins and efficiency and drugs then tested on lives animals to establish a safe dose for humans and any side effects
What happens during clinical testing?
The drug is first tested on healthy human volunteers to ensure that it’s safe to use and has no other effects on the body’s and the drug then is test on patients either the disease to determine its efficacy, dosage is slowly increased until an upper limit is established
What are placebos?
A substance that appears just like the real drug but has no effect on the recipient
What is a blind trial?
Where the participants don’t know whether they are receiving the new drug or the placebo
What is a double-blind trial?
Neither the participants nor the doctors know who is receiving the new drug or the placebo
What is the problem associated with using placebos on patients with a disease?
It’s unethical to prescribe a sick patient with a placebo knowing that it will not help their condition improve
What are monoclonal antibodies?
Antibodies that are clones from one parent cell and are specific to one type of antigen
How are monoclonal antibodies produced?
Specific antigen infected into an animal, B-lymphocytes producing complementary antibodies extracted, B-lymphocytes fuse with myeloma cells to form hybridoma cells, hydridoma cells cultured and monoclonal antibodies collected and purified
What are myeloma cells?
Type of tumour cells
What are the uses of monoclonal antibodies?
Detection of pathogens, location of cancer cells and blood clots, treatment of cancer and used in pregnancy test kits
What do pregnancy kits test for?
hCG in urine
What does a pregnancy test consist of?
A stick containing monoclonal antibodies specific to hCG - mAbs attached to a blue bead (free to move) and mAbs fixed to the test stick
What happens to the test stick of a woman is pregnant?
hCG in urine binds to mAbs attached to a blue bead, mAbs with hCG diffuse up dipstick, mAbs fixed to the stick binds to hCG and blue line forms
What happens to the test stick if a woman is not pregnant?
No hCG in urine so a blue isn’t formed
What is the advantage of using monoclonal antibodies to test for pathogens?
Specific to one particular antigen, very accurate and quick results
Why can monoclonal antibodies be used to target cancer cells?
Cancer cells have specific antigens called ‘tumour markers’ on their membrane and mAbs are specific to one type of antigens so can be targeted to ‘tumour markers’ without damaging other cells
How can monoclonal antibodies be used to diagnose cancer?
mAbs tagged to a radioactive substance, mAbs injected into the patient’s bloodstream, mAbs bind to ‘tumour markers’ on the cancer cells and emitted radiation is detected using a specialised scanner enabling doctors to determine the location of cancer cells
How can monoclonal antibodies be used to target drugs to cancer cells?
mAbs attached to an anti-cancer drug, mAbs injected into the patient’s bloodstream, mAbs bind to ‘tumours markers’ on cancer cells and anti-cancer drug destroys cancer cells
Why are cancer treatments that use monoclonal antibodies favoured over traditional treatments?
Radiotherapy and chemotherapy target rapidly dividing cells, healthy cells are damaged as a consequence, producing unpleasant side effects and mAbs only target cancer cells, reducing damage to normal cells
How can monoclonal antibodies be used to locate blood clots?
mAbs tagged to a radioactive substance, mAbs target and bind to a specific protein with in blood clot and radiation emitted by mAbs is detected, enabling the location of blood clots to be identified
