1 - Improving Health & Wellbeing
People working in the medical professions use their knowledge to diagnose and treat disease and illness, or to research new ways of treating disease. In both cases, medical scientists need to be aware of how the healthy body works as well as what may cause the body to become unhealthy.
1.1 The use (and misuse) of drugs
Candidates need to understand that:
Most drugs are legal and used to improve our quality of life by helping cure or prevent disease but many may cause side-effects if they are over-dosed. Some drugs are illegal and some are used for recreational purposes.
There is evidence that links respiratory and circulatory disorders to the misuse of tobacco and alcohol.
Drug testing for illegal drugs is carried out in some workplaces to improve the health and safety of employees.
Before new medicines can be released onto the market, they must be tested extensively and must be passed by the Medicines and Healthcare Regulatory Agency (MHRA).
Candidates need to:
1. Know that before a medicine can be used for treating a disease it undergoes extensive clinical trials.
2. Know that disease may be treated with medicines that contain useful drugs (eg penicillin is an antibiotic, aspirin is anti-inflammatory).
3. Know that most bacteria, but not viruses, may be killed by antibiotics.
4. Describe how some bacteria develop resistance to, or may not be easily treated by, antibiotics (for example, MRSA). Pathogens mutate spontaneously, producing resistant strains.
5. HT only: explain how resistant strains develop:
(a) antibiotics kill individual pathogens of the non-resistant strain
(b) individual resistant pathogens survive and reproduce, so the population of the resistant strain rises
(c) now, antibiotics are not used to treat non-serious infections such as mild throat infections in order to slow down the rate of development of resistant strains.
6. Know that some medicines, including painkillers, help to relieve the symptoms of disease, but do not provide a cure (for example, aspirin, paracetamol, treatments for high blood pressure, antidepressants and sleeping tablets).
7. Describe the problems caused by over-prescribing of antibiotics, including resistance and costs to the NHS.
8. Give examples of recreational drugs that may harm the body (alcohol, nicotine, antidepressants, amphetamines, barbiturates, heroin, cocaine and cannabis).
9. Know that some people may become dependent on, or addicted to, recreational drugs because the drug changes some of the chemical processes in the body, and they suffer withdrawal symptoms without them (for example, nicotine in tobacco).
10. Know that tobacco smoke contains substances that cause diseases of the respiratory and circulatory systems.
11. Know that tobacco smoke also contains carbon monoxide, which reduces the oxygen-carrying capacity of the blood.
12. Know that alcohol affects the nervous system by slowing down reactions (loss of self-control) and causes long-term damage to the liver and brain.
Within this context, candidates should be able to use scientific data and evidence to discuss, evaluate or suggest implications of the following:
■ the impact of legal (alcohol and tobacco) and illegal drugs on the body
■ the link between smoking and respiratory and circulatory diseases
■ the misuse of antibiotics, resulting in bacterial resistance and increased costs to the NHS
■ the issues caused by the over-use of symptom-relieving drugs
■ the issues of testing new drugs on animals and humans
■ personalisation of medicines.
1.2 The use of vaccines
Candidates need to understand that:
Medical scientists have known for a long time that recovery from some diseases, which we now know to be infections, leads to freedom from the same disease again, often for life. This is called immunity.
Medical scientists have developed vaccination, which can prevent certain diseases occurring in the first place.
Vaccination is the simplest, most efficient and cost-effective way to prevent life-threatening infections in the community.
Vaccination has helped to reduce the frequency of certain diseases in many parts of the world.
There are occasional scares about the safety of some vaccines. Some people believe vaccines overload our immune system, making it less able to react to other diseases that are now threatening our health such as meningitis, AIDS and cancer. Other people are concerned about possible side-effects of vaccines, although these are usually mild and not life-threatening.
Candidates need to:
1. Name some diseases caused by bacteria (tuberculosis, cholera, typhoid) and viruses (influenza, measles, mumps, rubella, polio).
2. Know that pathogens can enter the body through wounds, the respiratory system, the digestive system and by sexual transmission, as a result of unhygienic conditions or contact with infected people.
3. Know that some types of bacteria and viruses make us feel ill when they reproduce rapidly in the body (bacteria by producing toxins and viruses by causing cell damage).
4. Describe how platelets help to form a barrier to infection through a cut.
5. Describe how white blood cells help to defend against pathogens.
6. Describe how antibodies in the blood provide immunity to certain diseases.
7. Explain how vaccination protects humans from infection.
Within this context, candidates should be able to use scientific data and evidence to discuss, evaluate or suggest implications of the following:
■ the value to individuals and populations of being vaccinated against diseases, including concerns about side-effects and effects on the immune system
■ how the occurrence of diseases has changed as a result of increased use of vaccinations.
1.3 The use of ionising radiation in medicine
Candidates need to understand that:
Over time scientists have discovered that ionising radiation can be very helpful to us but also very harmful. They have found out that certain parts of the electromagnetic spectrum we use in our daily lives pose hazards that are specific to the type of electromagnetic wave.
Medical professionals diagnose and treat certain diseases, such as cancer, by using ionising radiation. Both professionals and patients need to be monitored and protected from the harmful effects of the radiation.
Radiotherapy is the treatment of cancer using high-energy (ionising) radiation. The ionising radiation damages or destroys cells in the area being treated, making it impossible for the cancer cells to continue to grow.
Before treatment with ionising radiation there are ethical issues that may have to be considered.
Candidates need to:
1. Know that X-rays and gamma rays are examples of transverse waves.
2. Know that X-rays and gamma rays are a form of electromagnetic radiation.
3. Understand that ionising radiation kills living cells and because of this can be used to treat cancer.
4. State the characteristics and properties of the three main types of nuclear radiation emitted continuously by radioactive sources (alpha particles, beta particles and gamma rays).
5. Describe the characteristic properties of X-rays (penetration) that enable them to be used to diagnose medical disorders.
6. Know that some medical imaging equipment involves the use of gamma rays, which can be detected using a gamma camera.
7. Know that the use of high-energy radiation can be dangerous and needs to be monitored.
8. Explain why people who work with radiation wear film badges and why these are monitored regularly to check the levels of radiation absorbed.
9. Be able to describe the construction of a film badge.
Within this context, candidates should be able to use scientific data and evidence to discuss, evaluate or suggest implications of the following:
■ the advantages and disadvantages of using ionising radiation for the diagnosis (including medical tracers) and treatment of diseases
■ the care of health workers who use ionising radiation as part of their everyday work
■ ethical issues that may need to be considered by doctors and patients before the treatment of cancers with ionising radiation.
Suggestions for practical work that could be used to support Theme 1
It is the responsibility of the centre to be aware of the health and safety implications of any practical work, and to ensure that risk assessments for practicals are carried out.
■ Use pre-inoculated agar in Petri dishes to evaluate the effect of disinfectants and antibiotics.
■ Investigate the effects of drugs (caffeine-based drinks, sleeping pills, alcohol) on Daphnia heartbeat rate.
