B5 - Health, Disease and the Development of Medicines Flashcards
What is the definition of
health?
and who is this according to?
a state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity
according to the World Health Organisation (the WHO)
Define
disease.
a condition where part of an organism doesn’t function properly
What are the
two different types of disease?
and what do these mean?
- Communicable - diseases that can be spread between individuals
- Non-communicable - diseases that can’t be transmitted between individuals
Define
pathogen.
an organism that causes communicable diseases
What are some exmaples of
pathogens?
(4)
- viruses
- bacteria
- fungi
- protists
What are the symptoms/effects of
cholera?
and what pathogen causes this?
diarrhoea
a bacterium called Vibrio cholerae
What are the symptoms/effects of
tuberculosis?
and what pathogen causes this?
coughing and lung damage
a bacterium called Mycobacterium tuberculosis
What are the symptoms/effects of
malaria?
and what pathogen causes this?
damage to red blood cells and (in severe cases) to the liver
a protist
What are the symptoms/effects of
stomach ulcers?
and what pathogen causes this?
stomach pain, nausea and vomiting
a bacterium called Helicobacter pylori
What are the symptoms/effects of
ebola?
and what pathogen causes this?
haemorrhagic fever ( afever with bleeding)
ebola virus
What are the symptoms/effects of
chalara ash dieback?
and what pathogen causes this?
leaf loss and bark wounds
a fungus that infects ash trees
How does
cholera spread?
and how can you reduce/prevent transmission?
via contaminated water sources
make sure that people have access to clean water supplies
How does
tuberculosis spread?
and how can you reduce/prevent transmission?
through air when infected individuals cough
infected people should avoid crowded public spaces, practic good hygiene and sleep alone
their homes should also be well-ventilated
How does
malaria spread?
and how can you reduce/prevent transmission?
mosquitos act as animal vectors
(they pass on the protist to humans but don’t get the disease themselves)
use mosquito nets and insect repellent to prevent mosquitos carrying the pathogen from biting people
How do
stomach ulcers spread?
and how can you reduce/prevent transmission?
oral transmission
(e.g. swallowing conaminated water or food)
have clean water supplies and hygienic living conditions
How do
ebola spread?
and how can you reduce/prevent transmission?
via bodily fluids
isolate infected individuals and sterilise any areas where the virus may be present
How do
chalara ash dieback spread?
and how can you reduce/prevent transmission?
it is carried through the air by the wind
(also spreads when diseased ash trees are moved between areas)
remove young, infected ash trees and replant with different species
restrict the import or movement of ash trees
Describe the
lytic pathway.
(of viruses) (4 steps)
- The virus attaches itself to a specific host cell and injects it genetic material into the cell.
- The virus uses proteins and enzymes in the host cell to replicate its genetic material and produce the components of new viruses.
- The viral components assemble.
- The host cell splits open, releasing the new viruses, which infect more cells.
Describe the
lysogenic pathway.
(of viruses) (3 steps)
- The injected genetic material is incorporated into the genome (DNA) of the host cell.
- The viral genetic material gets replicated along with the host DNA every time the host cell divides - but the virus is dormant and no new viruses are made.
- Eventually, a trigger causes the viral genetic material to leave the genome and enter the lytic pathway.
Define
STI.
an infection that is spread through sexual contact
What is
Chlamidya?
and what effect does it have?
a type of bacterium (that behaves similarly to a virus as it can only reproduce inside host cells)
it can result in infertility
How can the
spread of chlamidya be reduced?
(3)
- wearing a condom during sex
- screening indivudals so that they can be treated for the infection
- avoid sexual contact
What is
HIV?
and what effect does it have?
Human Immunodeficiency Virus
it kills white blood cells and eventually leads to AIDS
What is
AIDS?
Acquired Immune Deficiency Syndrome, when the infected person’s immune system deteriorates and eventually fails - causing the person to be very vulnerable to infections by other pathogens
How is
HIV spread?
and how can transmission be prevented? (3)
via infected bodily fluids
(e.g. blood semed, vaginal fluids)
- use a condom when having sex
- avoid sharing needles
- screening
What are some
physical plant defences?
and how do these work? (2)
- Waxy cuticle - stops pathogens from entering them or pests damaging them. Also stops water collecting on the leaf, which could reduce the risk of infection by pathogens that are transferred between plants in water.
- Cell walls - form a physical barrier against pathogens that make it past the waxy cuticle.
What
chemical defences do plants have?
(2)
- produce antiseptic chemicals which kill bacterial and fungal pathogens
- produce chemicals to deter pests from feeding on their leaves
What
plant chemicals have been used as drugs to treat human diseases?
(or relieve symptoms) (2)
- Quinine (from the bark of the cinchona tree) - used as treatment for malaria
- Aspirin (developed from a chemical dound in the bark and leaves of willow trees) - used to relieve pain and fever
How can
plant diseases be detected?
(4)
- observations by plant pathologists
- changing the environmental conditions and observing any change in the plant’s symptoms
- analysing the distribution of diseased plants
- laboratory-based diagnostic testing
What are some
physical barriers of the human body?
(to stop pathogens from entering) (5)
- skin - acts as a barrier
- blood clots - seals cuts and keeps microorganisms out
- hairs and mucus in your nose - trap particles that could contain pathogens
- mucus in the lungs - trap particles that could contain pathogens
- cilia in the lungs- waft the mucus up to the back of the throat where it can be swallowed
What are some
chemical barriers of the human body?
(to stop pathogens from entering) (2)
- the stomach produces hydrochloric acid that kills most pathogens that are swallowed
- the eyes produce lysozyme (in tears) which kill bacteria on the surface of the eye
Describe the
specific immune response by B-lymphocytes.
(4 steps)
- Every pathogen has unique molecules on its surface called antigens.
- When your B-lymphocytes come across an antigen on a pathogen, they start to produce proteins called antibodies.
- These bind to the new invading pathogen, so that it can be found and destroyed by other white blood cells. (The antibodies produced are specific to the pathogen.)
- The antibodies are then produced rapidly and flow all around the body to find all similar pathogens.
How is the
secondary immune response faster and stronger?
(4 steps)
- As well as antibodies, memory lymphocytes are also produced in response to a foreign antigen.
- These remain in the body for a long time and ‘remember’ a specific antigen.
- If the same pathogen enters the body again, there are more cells that will recognise and produce antibodies against it.
- This secondary immune response is faster and stronger.
and often gets rid of the pathogen before you begin to show any symptoms
How does
immunisation work?
(3 steps)
- Dead or inactive pathogens are injected into the body.
- The antigens trigger memory lymphocytes to be made.
- If live pathogens of the same type get into the body, there will already be memory lymphocytes that can cause a fast secondary immune response.
What are the positives and negatives of
immunisation?
(1+, 2-)
+epidemics can be prevented if a large percentage of the population are immunised
-immunisation doesn’t always work - sometimes it doesn’t give you immunity
-you can sometimes have a bad reaction to a vaccine
What are
monoclonal antibodies?
lots of identical antibodies
What are some uses of
monoclonal antibodies?
- pregnancy tests
- cancer treatment
- finding blood clots
How are
monoclonal antibodies used in pregnancy tests?
(4 steps)
- The bit of the stick where you wee has some antibodies to the hormone, with blue beads attached.
- The test strip has some antibodies to the hormone stuck on it.
- If you’re pregnant, the hormone binds to the antibodies on the blue beads and this binds to the antibodies on the strip. So, the blue beads get stuck on the strip, turning it blue.
- If you’re not pregnant, the urine still moves up the stick, carrying the blye beads as there’s nothing to stick these to the test strip.
Describe how
monoclonal antibodies are used to diagnose cancer.
(4 steps)
- The monoclonal antibodies are labelled with a radioactive element.
- These are given to the patient through a drip and go into the blood and are carried around the body.
- When the antibodies come into contact with the cancer cells the bind to the tumor markers.
- A picture of the patient’s body is taken using a special camera that detects the radioactivity.
Describe how
monoclonal antibodies can target drugs to cancer cells.
(4 steps)
- An anti-cancer drug is attached to monoclonal antibodies.
- The antibodies are given to the patient through a drip.
- The antibodies target the cancer cells because they only bind to the tumour markers.
- The drug kills the cancer cells but doesn’t kill any normal body cells near the tumour.
This side effects of this are lower than for other drugs or radiotherapy.
Describe how
monoclonal antibodies are used to find blood clots.
(4 steps)
- When blood clots, proteins in the blood join together to form a solid mesh.
- Monoclonal antiboides have been developed that bind to these proteins.
- You can attach a radioactive element to these antibodies and inject them into the body.
- If you take a picture using a camera that picks up the radiation, the blood clot can be detected.
How do
antibiotics work?
by inhibiting processes in bacterial cells, but not in the host organism
What are the
general stages of development of new drugs?
(3)
- Drug discovery.
- Drug development (preclinical + clincal testing).
- Drug approval
What are the stages of
preclinical testing?
(2)
- Drugs are tested on human cells and tissues in the lab.
- The drug is tested on live animals in order to test that the drug works, to find out how toxic it is and to find the best dosage.
What are the stages of
clinical testing?
(3)
- The drug is tested on healthy volunteers to ensure that it doesn’t have any harmful side effects when the body is working normally.
- If these results are good, the drug can be tested on people suffering from the illness. This helps to determine the optimum dose.
- Next, patients are randomly put into two groups, one is given the new drug and the other is given a placebo.
What do
antibiotics do?
kill bacteria inside the body
What do
antiseptics do?
kill bacteria outside the body
What does an
autoclave do?
uses steam at a high pressure and temperature to kill and microorganisms present
Give some examples of
aseptic technique.
(4) (for the bacterial growth practical)
- sterilise the petri dishes and growth medium before use (using an autoclave)
- sterilise the inoculating loop by passing it through a hot flame
- keep liquid bacterial cultures in a vial with a lid
- cover the Petri dish with a lid after transferring the bacteria to it
Define
risk factors.
things that are linked to an increase in the likelihood that a person will develop a certain disease during their lifetime
Why is
smoking a major risk factor associated with cardiovascular disease?
(3)
- nicotine in a cigarette smoke increases heart rate which increases blood pressure
- high blood pressure damages artery walls which contributes to the build up of fatty diposits in the arteries, these deposits restrict blood flow and increase the risk of a heart attack or stroke
- smoking increases the risk of blood clots forming in arteries, which can restrict or block blood flow, leading to a heart attack or stroke
What are some risk factors of
cardiovascular disease?
(4)
- smoking
- drinking too much alcohol
- lack of exercies
- a diet high in saturated fat
What is the formula for
BMI?
BMI = mass / height^2
What
BMI is classified as obese?
30 or over
Why isn’t BMI always a
reliable measure of obesity?
athletes have lots of muscle, which have a higher mass than fat, so can come out with a high BMI even if they’re not overweight
What is the equation for your
waist-to-hip ratio?
waist circumference / hip circumference
What waist-to-hip ratio is classified as
obese?
above 1.0 for males
above 0.85 for females
What is
cardiovascular disease?
any disease associated with your heart and blood vessels
What are
arteries?
blood vessels that carry blood away from the heart
What is
cholesterol?
a fatty substance that the body needs to make things like cell membranes
too much cholesterol in the blood can cause fatty deposits to build up in the arteries, restricting blood flow
When does a
heart attack occur?
when a blood clot in an artery supplyin the heart muscle deprives the heart of oxygen
When does a
stroke occur?
when a blockage in the brain deprives the brain of oxygen
What
drugs can reduce the risk of a heart attack or stroke?
(3)
- Statins - reduce the amount of cholesterol in the bloodstream
- Anticoaglulants - make blood clots less likely to form
- Antihypertensives - reduce blood pressure
What are
stents?
and what do they do?
tubes that are inserted inside arteries
they keep the arteries open making sure that blood can pass through to heart muscles - lowering the risk of a hart attack
What is
coronary bypass surgery?
a surgery where a piece of healthy blood vessel is taken and used to bypass a blocked blood vessel
