What factors increase the risk of heart disease?
1. Heart muscle cells need their own blood supply to supply oxygen and glucose for respiration;
2. Arteries have thick wall due to high pressures and veins have valves so blood only flows back to heart;
3. Fatty deposits in the blood vessels supplying the heart muscle block them and can produce a ‘heart attack’;
4. Heart disease is usually caused by lifestyle factors and/or genetic factors, not microorganisms;
5. Lifestyle factors include poor diet, stress, cigarette smoking, excessive alcohol intake;
6. Heart disease is more common in the UK than in non-industrialised countries;
7. Regular moderate exercise reduces the risk of developing heart disease;
What are antibiotics, and why can they become less
1. We can kill bacteria and fungi, but not viruses, using chemicals called antibiotics;
2. Over a period of time bacteria and fungi may become resistant to antibiotics;
3. Mutations in the genes of microorganisms can lead to varieties which are less affected by the antibiotic;
4. To reduce antibiotic resistance we should only use antibiotics when necessary and always complete the course;
5. New drugs are first tested for safety and effectiveness using human cells grown in the laboratory and animals;
6. Human trials may be carried out on volunteers to test for safety and on ill people to test for safety and effectiveness.
7. describe and explain the use of ‘blind’ or ‘double-blind’ human trials in the testing of a new medical treatment;
8. Placebos are not commonly used in human trials as it would be unethical to give an ill person a placebo.
What are vaccines and how do they work?
1. Microorganisms may enter the body and cause illness before the immune system can destroy them;
2. Vaccinations provide protection from microorganisms by establishing antibodies before infection;
3. A vaccination contains a usually safe form of a disease-causing microorganism;
4. Vaccination can never be completely safe, since individuals have varying degrees of side-effects from a vaccine;
5. To prevent epidemics of infectious diseases, it is necessary to vaccinate a high percentage of a population;
6. There is a conflict between a person’s right to decide about vaccination for themselves or their children, and what is of benefit to society as a whole;
7. New vaccines against influenza have to be developed regularly because the virus changes very quickly;
8. It is difficult to develop an effective vaccine against the HIV virus (which causes AIDS) because the virus damages the immune system and has a high mutation rate;
How do our bodies resist infection?
1. Natural barriers reduce the risk of microbes entering the body (skin, chemicals in tears, sweat and stomach acid);
2. In suitable conditions (such as inside the body) microorganisms can reproduce rapidly;
3. Symptoms of a disease are caused by damage done to cells by the microorganisms or the poisons (toxins) they produce;
4. Our bodies have immune systems to defend themselves against the invading microorganisms;
5. White blood cells can destroy microorganisms by engulfing and digesting them, or by producing antibodies;
6. A different antibody is needed to recognise each different type of microorganism;
7. Once the body has made the antibody to recognise a particular microorganism it can make it again very quickly,
therefore protecting against that particular microorganism.