B5: Health, Disease A D The Development Of Medicines Flashcards
What is the category of pathogen for Cholera ?
Bacteria
What are the effects/symptoms of cholera ?
Diarrhoea
How is cholera spread?
Water
What category of pathogen is Tuberculosis?
Bacteria
What are the effects/symptoms of tuberculosis?
Lung damage, coughing
How is tuberculosis spread ?
Airborne
What category of pathogen is chalara ash dieback ?
Fungi
What are the effects/symptoms of chalara ash dieback ?
Leaf loss, bark lesions
How is chalara ask dieback spread ?
Airborne
What category of pathogen is malaria?
Protist
What are the effects/symptoms of malaria?
Damage to blood and liver
How is malaria spread ?
Animal vector (mosquito)
What category of pathogen is HIV?
Virus
What are the effects/symptoms of HIV?
Destroys white blood cells and leads to onset of AIDS
How is HIV spread ?
Body fluids
What category of pathogen is helicobacter ?
Bacteria
What are the effects/symptoms of helicobacter ?
Can lead to stomach ulcers
How is helicobacter spread ?
Oral transmission
What category of pathogen is Ebola ?
Virus
What are the effects/ symptoms of Ebola ?
Causes fever accompanied by severe bleeding
How is Ebola spread ?
Body fluids
What does communicable disease mean?
A disease that can be transmitted
What does non communicable disease mean?
A disease that can’t be transmitted
What is the meaning of Health ?
A state of physical, mental and social wellbeing
What is a pathogen?
A micro organism that causes disease
What do viruses need in order to reproduce?
A host cell
What are the 2 ways in which a virus can reproduce in a host cell ?
Lytic and lysogenic pathways
What are the 4 steps to lytic pathway?
- Using a host cell the virus replicates it’s DNA
- These are assembled to form new virus particles
- Once the host cell is filled with the new virus particles it bursts (this is called lysis)
- the process Is repeated with nearby cells
What are the 3 steps to lysogenic pathways ?
- The virus uses a restriction enzyme to insert its DNA into a host cell (the DNA fragments are called plasmids
- The host cell replicates and the viral DNA is copied in the process
- The lytic cycle begins at this point
What is the pathogen for chlamydia?
Bacteria
How is chlamydia spread?
Sexual contact
What are the symptoms of chlamydia ?
Painful urination and infertility
What are the physical defence systems against disease in pants ?
Waxy cuticle layer
Give an example of the bodies physical defence barrier ?
Skin, blood clotting, respiratory tract
Give an example of the body chemical barriers ?
Tears, saliva/mucus and hydrochloric acid
What are memory lymphocytes?
A response to a foreign antigen
Give an example of a non communicable disease?
Cancer, cardiovascular disease
What is an antibiotic?
A substance that kills or inhibits the growth of bacteria
What are the stages or drug development?
Screening for potential drug
Preclinical testing
Clinical trial
Approval be a medical agency
What is a placebo ?
A substance that appears just like the real drug but has no effect on the recipient
Define disease ?
A disorder of the body of mind that negatively affect on individuals health
What are 2 types of disease ?
Communicable and non communicable
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 individual’s immune system making them increasingly susceptible to other infections.
Describe the physical defence system within plants?
• Waterproof waxy cuticle - surface barrier preventing the entry of pathogens
• Cellulose cell wall - further barrier against pathogens
Give some examples of chemical barriers in plants ?
• Secretion of toxins to reduce damage by pests e.g. stinging nettles
• Production of antibacterial chemicals that kill bacterial pathogens
Why are chemicals produced by plants useful ?
They produce physiological effects on the body so can be used in medicine to treat diseases
Give an example of a medicine derived from plants ?
Quinine -anti malarial
Aspirin- painkillers
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
• Important in maintaining human food security
How can plant diseases be detected and identified in the field?
• Observation of symptoms e.g. Chalara ash dieback disease causes bark lesions. Books and online resources aid identification
• Analysis of the distribution of infected plants can indicate the type of pathogen involved and its mode of transmission e.g. airborne
• Changing environmental conditions to eliminate other causes such as nutrient deficiencies or water-logged soils
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
• Analysis of DNA to identify any pathogen DNA in a tissue sample
What is a non specific defence?
1.Always present
2.Same for all organisms
3.Prevents pathogens from entering the body
Give some examples of the body’s physical defence system ?
• Skin - protective surface barrier
• Blood clotting - platelets seal wounds preventing entry of pathogens into the blood
• Respiratory tract - mucus traps pathogens, cilia waft mucus to the back of the throat where it is swallowed
Give some examples of the body’s chemical defence system?
• Tears - contain lysozyme which digests bacterial cell walls, killing bacteria and protecting the eye
• Hydrochloric acid in stomach - acidic pH kills pathogens that are swallowed
What is the immune system?
• The body’s defence against pathogens once they have entered the body
• Aims to prevent or minimise disease caused by pathogens
How do white blood cells detect pathogens in 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 (type of WBC) produce antibodies in response to a particular antigen
• Each antibody is specific to an antigen and binds to it
• Antibodies ‘tag’ pathogens or clump them together, disabling them so that they can be killed 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
• Provide immunity - if the body is re-infected, antibodies are produced more rapidly and the pathogen is destroyed before it can produce disease symptoms
What is a vaccination?
• Deliberate exposure of an individual to foreign antigens
• Triggers an immune response (produces antibodies) and provides immunity (due to memory cells)
• The individual does not contract the disease that they are being immunised against
Describe the components of a vaccine?
Dead, weakened or inactivated pathogens with their surface antigens still present
What are the benefits of vaccinations?
• Herd immunity - vaccination of a significant proportion of the population gives some protection to individuals who are not immune
• Helps to prevent epidemics and pandemics
What are the drawbacks of vaccinations?
• Not guaranteed to work
• Inactivated pathogens may mutate and become pathogenic
• May cause an adverse reaction
• Vaccination programmes are costly
What is an antibiotic?
• A substance that kills or inhibits the growth of bacteria (no effect on viruses)
• No effect on cells in the host organism
• Produced by living organisms e.g. fungi
Describe how ‘target’ molecules for new medicines can be identified?
• Comparisons of the genomes of unaffected individuals and those who are affected by a disease to identify potential disease-causing alleles
• The alleles themselves or the proteins that they code for can be used as a target
Outline the stages of drug development?
- Screening for potential drugs
- Preclinical trials
- Clinical trials
- Approval by a medical agency
Describe 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
• 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 tested on cultured human cells and using computer models to determine its toxicity (potential to cause damage) and efficiency
• Drug then tested on live animals to establish a safe dose for humans and observe any side effects
What happens during clinical testing?
• The drug is first tested on healthy human volunteers to ensure that it is safe to use and has no other unwanted effects on the body
• Drug then tested on patients with the disease to determine its efficacy. Dosage is slowly increased until an upper limit is established. Optimum dosage is found.
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
• Prevents the patient’s bias affecting the results
What is a double-blind trial?
• Neither the participants nor the doctors know who is receiving the new drug or the placebo
• Prevents bias from doctors when analysing the results
What are monoclonal antibodies (mAbs)?
• Antibodies that are clones from one parent cell
• Specific to one type of antigen
Describe how monoclonal antibodies are produced?
- Specific antigen injected into an animal
- B-lymphocytes producing complementary antibodies extracted
- B-lymphocytes fuse with myeloma cells to form hybridoma cells
- Hybridoma cells cultured
- Monoclonal antibodies collected and purified
What are myeloma cells?
A type of tumour cell
Outline the uses of monoclonal antibodies?
• Detection of pathogens
• Location of cancer cells and blood clots
• Treatment of cancer
• 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 (mAbs) specific to hCG:
• mAbs attached to a blue bead (free to move)
• mAbs fixed to the test stick
Describe what happens to the test stick if 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 bind to hCG
• Blue line forms
Describe what happens to the test stick if the pathogen is not present?
No hCG in urine so a blue line is not formed
What is the advantage of using monoclonal antibodies to test for pathogens?
• Specific to one particular antigen
• Very accurate
• Quick results
Why can monoclonal antibodies be used to target cancer cells?
• Cancer cells have specific antigens called ‘tumour markers’ on their membranes
• mAbs are specific to one type of antigen so can be targeted to ‘tumour markers’ without damaging other cells
Describe how monoclonal antibodies can be used to diagnose cancer?
• mAbs tagged to a radioactive substance
• mAbs injected into the patient’s bloodstream
• mAbs bind to ‘tumour markers’ on cancer cells
• 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 ‘tumour markers’ on cancer cells
• 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 (e.g. hair follicle cells, bone marrow cells) are damaged as a consequence, producing unpleasant side effects
• 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 specific proteins in blood clots
• Radiation emitted by mAbs is detected, enabling the location of blood clots to be identified
Give some examples of non-communicable diseases?
• Cancer
• Diabetes
• Cardiovascular diseases
• Chronic respiratory diseases e.g. asthma
What is a risk factor?
A variable associated with a greater chance of developing a disease or infection
Outline the factors that can affect the risk of developing a non-communicable disease?
• Lifestyle factors e.g. diet, exercise, alcohol, smoking
• Environmental factors e.g. exposure to pollution
• Genetics e.g. alleles that increase the risk of cancer
Describe how exercise affects the risk of some non-communicable diseases?
• Regular exercise decreases fat stores, reducing obesity (a risk factor of type 2 diabetes)
• It decreases heart rate, recovery time and blood pressure, lowering the risk of cardiovascular disease
Describe how diet affects the risk of some non-communicable diseases?
• Diet high in saturated fat raises blood cholesterol levels, increasing the deposition of fatty deposits in the arteries . greater risk of CVD
• Obesity and the consumption of large amounts of simple-sugars increases the risk of type 2 diabetes
• Malnourishment increases the risk of deficiency diseases
What is the Body Mass Index (BMI)?
A value based on height and mass used to categorise an individual as underweight, normal weight, overweight or obese.
Give an example of a deficiency disease?
• Scurvy (vitamin C deficiency)
• Anaemia (iron deficiency)
Why isn’t BMI always an accurate measure of obesity?
Fat and muscle tissue cannot be distinguished so athletes may be incorrectly categorised as obese.
What does a waist-to-hip ratio higher than 1.0 in males or 0.85 in females indicate?
• Abdominal obesity
• Increased risk of developing type 2 diabetes
Describe how alcohol affects the risk of some non-communicable diseases?
• Alcohol broken down into toxic products in the liver which build-up and cause cirrhosis (scarring of liver tissue)
• Alcohol raises blood pressure thus increasing the risk of CVD
• Toxic products in alcohol can cause mutations to DNA, increasing the risk of cancer (mouth, throat, liver etc.)
Describe how smoking affects the risk of some non-communicable diseases?
• Nicotine raises heart rate, increasing the risk of CVD
• Carbon monoxide lowers the ability of red blood cells to carry oxygen, heart rate increases, increasing the risk of CVD
• Carcinogens in tar can cause mutations to DNA, increasing the risk of cancer (mouth, throat, lung etc.)
• Smoking increases the risk of lung diseases e.g. chronic bronchitis
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 lung cancer
• Exposure to UV radiation damages DNA, increasing the risk of DNA mutations and skin cancer
How do genetics affect the risk of some non-communicable diseases?
The risks of some diseases such as type 2 diabetes, lung cancer and CVD are increased if a family member has had these conditions.
Faulty genes can be inherited which increase the risk of conditions such as breast cancer.
How do diseases interact with each other?
• Some diseases may cause other infections to develop e.g.
HIV weakens the immune system, making an individual more susceptible to other infections such as TB.
• Some diseases reduce the risk of contracting other infections e.g. Trichinosis reduces the development of Crohn’s disease.
Describe 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 which have limited resources
• Increased pressure on NHS to provide treatment to a larger number of patients. Sickness-related absence impacts a country’s economy
• High prevalence of malnutrition in LEDCs slows the development of such countries which in turn impacts global development
What is cardiovascular disease (CVD)?
• Group of diseases affecting the heart or blood vessels
• Build up of fatty deposits on the walls of the arteries forms atheromas which reduce blood flow to muscle tissue
• Blood clots may form, blocking the arteries and stopping blood flow completely. This can lead to a heart attack or stroke.
How can CVD lead to a heart attack?
• Obstruction of a coronary artery (supplies heart muscle)
due to an atheroma or blood clot
• Results in loss of blood supply to an area of heart muscle
• This causes death of the cells and leads to a heart attack
How can CVD be treated?
• Improving diet and lifestyle
• Medication
• Surgery
What 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
• 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
• Anticoagulants
• Antihypertensives
Outline the benefits vs the 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
Outline the benefits vs the 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
Outline the benefits vs the risks of using antihypertensives to treat CVD?
• Antihypertensives lower blood pressure, reducing damage to artery walls and the build up of atheromas
• However, they can have unpleasant side-effects such as headaches, dizziness or fainting
What are stents?
• Small, hollow tubes inserted into the lumen of arteries to keep them open
• 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
• Blood clots may stick to stents
What is a coronary bypass?
Using a blood vessel from another region of the body (e.g. leg, arm) to divert blood around a blockage in the coronary artery.
What does a heart transplant involve?
• Replacing a damaged heart with a donated heart
• Immunosuppressant drugs taken to prevent organ rejection
Describe the benefits of heart surgery?
• Lifesaving
• Can provide a permanent solution to a disease
Describe the risks of heart surgery?
• Involves many risks e.g. infection, excessive bleeding etc.
• Difficult to find a suitable donor
• Risk of rejection
• Immunosuppressant drugs must be taken for life
• Long recovery time
• Expensive
