Health, Disease And The Development Of Medicines Flashcards
World health organisation definition of health
A state of complete physical, mental and social well-being, and not merely in the absence of infirmity.
Disease
A condition where part of an organism doesn’t function properly.
Communicable disease
Diseases that can be spread between individuals.
Noncommunicable diseases
Diseases that can’t be transmitted between individuals
How do diseases affect your susceptibility to other diseases?
Your body may become weakened by the disease, so it’s less able to fight others off.
Pathogens
Organisms that cause communicable disease.
Cholera pathogen and symptoms
A bacterium (vibrio cholorae) Symptoms include diarrhoea
Transmission and prevention of cholera
Spread via water.
Prevented by making sure people have access to clean water supplies.
Tuberculosis pathogen and symptoms
A bacterium (mycobacterium tuberculosis). Symptoms include coughing and lung damage
Tuberculosis transmission and prevention
Spread via droplets in the air.
Prevented by the infected avoiding public spaces, practicing good hygiene and sleeping alone in well ventilated homes.
Malaria pathogen and symptoms
A protist which damages red blood cells and sometimes liver.
Transmission and prevention of malaria
Animal vectors (mosquitoes) passing on disease to humans while being immune. Use of mosquito nets and insect repellent deter mosquitoes.
Stomach ulcers pathogen and symptoms
Bacterium called helicobacterplyori
Causes stomach pains, nausea and vomiting
Transmission and prevention of stomach ulcers
Spread via oral transmission (food and drink)
Prevented by having clean water supplies and hygienic living conditions
Ebola pathogen and symptoms
Virus
Symptoms include haemorrhagic fever (fever with bleeding)
Transmission and prevention of Ebola
Transmitted by bodily fluids
Preventing by isolating infected and sterilising places where bacteria is present.
Chalara ash dieback pathogen and symptoms
Fungus
Symptoms include leaf loss and bark lesions
Transmission and prevention of chalara ash dieback
Transmission via air (wind) and movement of trees
Prevented by removing young, infected trees and replanting with different species as well as restricting the import of ash trees
What do viruses have to do in order to reproduce?
Infect living cells
Lytic pathway
Virus attaches itself to a specific host cell, injecting its genetic material inside the cell.
Proteins / enzymes are used to replicate genetic material and produce components of new viruses which then assemble.
The host cells bursts/splits open releasing new viruses that infect new cells.
Lysogenic pathway
Virus’ genetic material is incorporated into the genome of the host cell and then is replicated with every time the host sells divides. Virus is dormant and no new viruses are made.
Eventually a trigger (eg the presence of a chemical) causes the viral genetic material to leave the genome and enter the lytic pathway.
STI
Sexually transmitted infection
Chlamydia pathogen and symptoms
Caused by a bacterium which behaves similarly to a virus.
Doesn’t always display symptoms but can cause infertility.
Transmission and prevention of chlamydia
Transmission via sexual contact
Prevented by wearing a condom, getting screenings or avoiding sexual contact
HIV (Human immunodeficiency virus) pathogen and symptoms
Virus that kills white blood cells, leading to the shutting down of the immune system. Leads to AIDS (acquired immunodeficiency syndrome) meaning the person is v vulnerable to other pathogens.
Transmission and prevention of HIV
Spread via bodily fluids.
Prevented by using a condom, not sharing needles, screenings and treatment
Plants physical defences against pathogens and pests
WAXY CUTICLE, providing a barrier for pathogens not to enter or damage them and meaning water can’t collect on the leaf and transmit waterborne pathogens.
CELL WALLS made from cellulose form a barrier against pathogens that make it past the waxy cuticle
Plant’s Chemical defences against pathogens and pests
Production of ANTISEPTICS which kill bacterial and fungal pathogens and chemicals that can deter pests from feeding.
Things like quinine (treatment for malaria) and aspirin (relief of pain and fever) are chemicals from plants.
Detection of plant diseases in the field
Plant pathologists can observe and identify symptoms (eg. Galls may indicate Crown gall disease).
They can also analyse the distribution of diseased plants to identify pathogen involved, (eg patches may suggest soil transmission whereas random distribution may suggest airborne pathogens)
How do plant pathologists tell that symptoms aren’t down to environmental factors?
They change the environmental conditions and observing any change in the plant’s symptoms.
Diagnosis of plant disease in the lab
Detection of antigens- antigens can be detected on a sample of plant tissue( using monoclonal antibodies).
Detection of DNA- scientific techniques can identify small traces of a pathogens DNA in a sample of plant tissue
Human physical barriers against disease
SKIN is a barrier, if damaged BLOOD CLOTS seal cuts and keep microorganisms out.
HAIRS/MUCUS in youR nose trap pathogens
EPITHELIAL CELLS (cilia) waft mucus (produced by cells) to back of throat to be swallowed into stomach acid.
Human chemical barriers against pathogens
HYDROCHLORIC ACID in stomach kills most pathogens that are swallowed.
LYSOZYME (in tears) kills bacteria on surface of the eye
B-lymphocytes
A type of white blood cell that’s involved in a specific immune response.
Process of specific immune response
B lymphocytes come across antigens and produce antibodies that bind to the new invading pathogen so it can be found and destroyed by other white blood cells. These antibodies are SPECIFIC to that pathogen.
Antibodies are then produced rapidly and flow all around the body to find similar pathogens.
Antigen
Unique molecule on the surface of pathogens
Antibodies
Proteins that bind to and identify new, specific, invading pathogens so that they can be killed by other white blood cells.
What’s the response speed to a new pathogen in comparison to a pathogen that has entered the body before?
The response to a new pathogen is slow because there aren’t many b-lymphocytes that can produce its specific antibody. The body eventually produces enough antibodies to overcome the infection while symptoms appear. Memory lymphocytes are also produced that remain in the body for a long time and ‘remember’ a specific antigen, meaning the person is then immune and has a v quick response to the 2nd infection as it will be recognised immediately before many antibodies are produced so no symptoms appear.
Immunisation
Injecting dead/inactive antigenic pathogens into the body to trigger memory lymphocytes. This will mean a fast secondary immune response.
Pros of immunisation
Epidemics can be prevented by immunising a large majority of the population is immunised (herd immunity) so lots of people don’t die.
Some diseases like smallpox have been wiped out by immunisation
Cons of immunisation
Doesn’t always work
Sometimes you can have a bad reaction to a vaccine (eg swelling, fever or seizures)
Where are antibodies produced
At b-lymphocytes
Where are monoclonal antibodies produced from?
many clones of a single b-lymphocyte
Monoclonal antibodies
Identical antibodies produced from clones of a single b-lymphocyte. They only target one specific antigen
Process of production of monoclonal antibodies
A mouse is injected with your chosen antigen and so produce b-lymphocytes specific to that antigen.
B-lymphocytes are fused with myeloma cells to produce a hybridoma.
These hybridomas can be cloned and divide v quick to produce the same antibodies which are collected and purified.
Myeloma cell
A tumour cell
Hormone found in pregnant women’s urine
HCG
How do pregnancy tests work?
- )antibodies are stuck to blue beads on the strip where you piss
- )the test strip has more antibodies stuck onto it so they can’t move.
- if you are pregnant: HCG attaches to to the antibodies with blue beads which moves up the stick and eventually bonds to the other antibodies on the test strip, turning it blue.
- if you aren’t pregnant, the urine moves up the stick carrying blue beads but doesn’t stick to the test strip so it doesn’t go blue
Uses of monoclonal antibodies
Targeting, diagnosis and treatment of cancer cells
Blood clot identification
Pregnancy tests
Cancer cell proteins
Tumour markers
How do monoclonal antibodies target tumour markers?
You can produce monoclonal antibodies that will bind to those tumour markers and so help in the diagnosis and treatment of cancer.
How monoclonal antibodies are used to diagnose cancer?
Antibodies are labelled with a radioactive element and given to a patient via a drip, meaning it goes straight into the blood and is carried around the body.
They bind to the tumour markers while a picture is taken using a radioactivity sensing camera so the cancer cells show up brightly.
Doctors can then see where, how big and the transmission of the cancer.
How are monoclonal antibodies used to target drugs to cancer cells?
Anti cancer drugs are attached to monoclonal antibodies and given to the patient in a drip.
The antibodies target specific cancer cells using their tumour markers.
The drug then kills the cancer cells but doesn’t kill any normal body cells.
This means that the side effects for antibody-based drugs are lower than others
How are monoclonal antibodies used to detect blood clots?
Monoclonal antibodies bind to clot-causing proteins and can be attached to a radioactive element so when injected, can be detected for radiation to find a potentially harmful blood clot
How do antibiotics work?
They inhibit processes in bacterial cells, but not in the host organism (eg can stop process of bacterial cell walls so bacteria can’t divide but has no affect on human host cells as have no cell wall).
They don’t destroy viruses as viruses reproduce using your body cells, it’s v difficult to create a drug that destroys a virus without killing the body cells.
First stage of development of new drugs
Discovery of the drug (eg Fleming discovered penicillin as mould in Petri dish), can be seeked out as nowadays scientists use disease knowledge to identify molecules that can be used as drugs to fight disease.
Preclinical testing
Drugs are first tested on human cells and tissues in the lab (Cant be tested with drugs that affect whole/multiple body systems like drug for blood pressure).
Then drugs are tested on live animals to see whether drug works and analyse toxicity to find correct dosage
Clinical testing
Is then passed on to human volunteers in a clinical trial.
First is tested on healthy volunteers (so no harmful side effects web body is working normally).
If this is fine, drugs can be tested on people suffering from the illness to find optimum dose that’s most effective w fewest side effects.
Then 2 groups of patients are split up, one with the new drug and one with a placebo, allowing for the placebo effect. These are blind and mostly double blind so neither patient nor doctor knows until all results have been gathered so doctors can’t influence patients.
Order of drug development
Discovery
Preclinical testing
Clinical testing
Approval by a medical agency
How to make an agar plate
Hot Agar jelly is poured into Petri dishes to be cooled and set , inoculating loops (wire loops) transfer microorganisms to the agar jelly. Alternatively, a sterile dropping pipette and spreader can make an even covering of bacteria. The microorganisms then multiply.
School lab temperature for microorganism growth
25 degrees Celsius (harmful pathogens are less likely to grow at this temp)
Higher temps at normal labs to provide optimum temp for growth.
Antiseptics vs antibiotics
Antibiotics kill bacteria inside the body whereas antibiotics kill bacteria outside of the body.
How to investigate the effect of substances on bacterial growth
1 place paper discs soaked in different types of antibiotics (eg) on an agar plate with an even covering of bacteria, leave space between discs.
2 the antibiotic should diffuse into the agar jelly, while antibiotic resistant bacteria will remain, nonresistant strains will die and a clear area will be left around called an inhibition zone.
3 use a control (eg a paper disc not soaked in antibiotic) to make sure that it’s down to just the antibiotic
4 leave the plate for 48 hours @ 25 degrees
5 the more effective, the larger the inhibition zone.
Why do you use the aseptic technique?
As contamination of unwanted organisms will affect your results and can result in the growth of pathogens.
How do you sterilise the Petri dishes and growth medium?
By placing them in a machine called an autoclave, which uses steam and high pressure/temperature to kill microorganisms present.
How do you sterilise an inoculating loop?
Passing it through a hot flame to kill any unwanted organisms
How to prevent contamination in liquid bacterial cultures
Keep a lid on it while storing it in a culture vial, removing it for as little time as possible.
Why should you tape the lid of Petri dishes?
To stop air from getting in and contaminating it
Why should the Petri dish be stored upside down?
To stop drops of condensation from falling on the agar.
How do you compare the effectiveness of different antibiotics, antiseptics or plant extracts?
By looking at the relative sizes of inhibition zones
How do you compare relative sizes of inhibition zones other than by eye? (More accurate)
Calculate the areas of inhibition zones using their diameter.
Area = pi * r squared
This can also be used to calculate the area of a bacterial colony
Don’t open the Petri dish to measure
Risk factors
Things that are linked to an increase in the likelihood that a person will develop a certain disease during their lifetime (not guaranteeing that someone will get the disease). These can be unavoidable (eg age or gender)
What disease is smoking associated with? Why?
Cardiovascular disease
Nicotine increases heart rate and so blood pressure.
High blood pressure damages artery walls and so contributes to the distribution of fatty deposits in the arteries restricting blood flow and so increasing the risk of a heart attack/ stroke.
Smoking increases risk of blood clots in arteries which can restrict blood flow leading to a heart attack/stroke.
Malnutrition risk factors
Too many/ too few nutrients
Obesity risk factors
Not enough exercise and a diet high in fat/sugar
Drinking too much alcohol is associated with which diseases?
Liver disease (eg cirrhosis/ scarring of liver) As alcohol is broken down by enzymes in liver and some products are toxic. Can cause permanent liver damage.
Local effects with high levels of obesity, smoking, alcoholism
High occurrence of noncommunicable diseases, putting pressure on local resources of hospitals
National effects of noncommunicable diseases
Pressure on the national health service and decreases economy due to higher unemployment rate.
International effects of noncommunicable diseases
Can hold back a country’s development
BMI (body mass index)
Guide to help decide whether someone is underweight, normal, overweight or obese.
BMI= weight (kg)/ (height (m))squared
Con of BMI
Muscle weighs more than fat
Waist to hip ratio
Waist circumference/ hip circumference (cm)
Higher waist to hip ratio means…
More weight around your middle
Levels of waist to hip ratio indicating abdominal obesity
Above 1 for males
Above 0.85 for females
Cardiovascular disease
Any disease associated with heart and blood vessels
Arteries
Blood vessels carrying blood away from the heart.
Cholesterol
Fatty substance needed to make cell membranes but can build up in blood arteries restricting blood flow, depositing in places with arterial damage. Can trigger blood clots to form, possibly causing a heart attack or stroke.
Lifestyle changes for CVD
Eating a healthy, balanced diet low in saturated fat/ exercising regularly/ losing weight and stopping smoking
Statins
Reduce cholesterol in the bloodstream, slowing down the rate at which fatty deposits form.
Cause aching muscles and possibly liver damage
Anticoagulants
Reduce blood clots
Can cause uncontrollable bleeding
Antihypertensives
Reduce blood pressure and so damage to blood vessels
Can cause headaches and fainting
Stents
Tubes inserted inside the arteries to keep them open, lowering risk of heart attack
Artery can narrow over time as stent can irritate artery to cause scar tissue to grow. Patient also needs drugs to stop blood clotting on stent.
Coronary bypass surgery
When part of a blood vessel is blocked, a piece of healthy vessel bypasses the blocked section.
Heart transplant
When replacing the whole heart with a donor heart
Doesn’t always pump properly and body may reject it (need drugs to stop this)
These drugs make you more vulnerable to infection.
