Health, disease, and development of medicines

• Health


  A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
• What is the difference between communicable and non communicable diseases?


  Communicable diseases are spread between individuals, whereas non communicable diseases are not transmitted
• If you are affected by one disease, it could make you more susceptible to others as your body is weakened by the first and less likely to last fighting the others off.
• Pathogen


  A disease causing micro-organism. There are 4 types: viruses, bacteria, fungi, and protists.
• Cholera

  • Bacteria spread
  • Can cause diarrhoea
  • Spread via contaminated water
• Tuberculosis

  • Bacteria spread
  • Causes lung damage
  • Spreads through the air when the infected cough
• Malaria

  • Protist
  • Causes damage to red blood cells
  • Spreads via a vector, a mosquito
• Chalara Ash Dieback

  • Fungi
  • Causes leaf loss and bark wounds
  • Spread via the wind and air
• HIV

  • Virus
  • Causes destruction of white blood cells leading to the onset of AIDS
  • Spread via bodily fluids
  • Can be prevented by using a condom and avoiding sharing needles
• Chlamydia

  • Bacteria
  • Can result in infertility
  • Is prevented by wearing a condom during sex and avoiding sexual contact
• Physical barriers that provide protection from pathogens

  • Skin acts as a barrier to pathogens
  • Hair and mucus in your nose trap particles that could contain pathogen
  • Airways in the lungs produce mucus that traps pathogens and cillia which waft the mucus to the back of the throat
• Chemical barriers that protect us from pathogens

  • The stomach produces hydrochloric acid that kills most swallowed pathogens
  • The eyes produce a chemical called lysozyme which kills bacteria on the surface of the eye
• Immune system attacking pathogens

  White blood cells patrol pathogens and they contain:

  • Lymphocytes: produce proteins called antibodies that bind onto the pathogen and are specific to that pathogen so that these pathogens are found
  • Phagocytes: engulfs pathogens so that they are sucked into the cell
  • Memory lymphocytes: remember specific antigens so that next time more cells recognise it and are able to respond quicker.
• Immunisation


  Immunisation involves injecting inactive pathogens into the body that carry antigens. Even though they are harmless the body makes antibodies to destroy them. The antigens also trigger production of memory lymphocytes meaning that when live pathogens of the same type get into the body memory lymphocytes cause a faster immune response.
• Antibiotics


  Antibiotics work by inhibiting processes in bacterial cells but not the host organism. For example, some antibiotics inhibit the building of bacterial cell walls preventing the bacteria from dividing and eventually killing them.
• Developing new drugs: Discovering

  A drug has to be discovered first. Scientists use their knowledge of how a disease works to try and identify molecules that could be used as drugs to fight the disease
• Developing new drugs: Preclinical testing

  Drugs are first tested on human cells and tissues in the lab. They then test it on live animals to see if it works, to find out how toxic it is, and to find the best dosage.
• Developing new drugs: Clinical testing

  If it passes preclinical tests its tested on human volunteers. The drug is tested on healthy volunteers first to ensure there are no harmful side effects when the body is normal. Then, the drug is tested on people suffering the illness. The optimum dose is found (most effective with the least side effects). Patients are randomly put into two groups. One is given the new drug and the other is given a placebo. The test is double blind so no one knows which group is getting which in order to reduce subconscious influence.
• Developing new drugs: after passing clinical

  After passing every test, the drug needs to be approved by the medical agency to ensure it is effective and safe before treating patients
• Developing new drugs: stages

  1. Discovery
  2. Preclinical testing
  3. Clinical testing
  4. Approval by the medial agency
• Non communicable disease risk factors- Smoking

  Smoking is a major risk factor because:

  • Nicotine increases heart rate and blood pressure
  • High blood pressure damages artery walls which contributes to build up of fat in the arteries restricting blood flow
  • Increases the risk of blood clots forming in arteries which can restrict or block blood flow
  • Restricted flow can cause heart attacks or strokes
• Non communicable disease risk factors- lifestyle factors

  • A diet with too many or too few nutrients can lead to malnutrition
  • Lack of exercise and too much fat and sugar can lead to obesity
  • Drinking too much alcohol can cause liver disease because the products broken down by enzymes in alcohol can be toxic
• Non communicable disease risk factors- knock on effect

  Many non communicable diseases are caused by several different risk factors interacting with each other including cancer, liver and lung diseases, and obesity.
• Non communicable diseases local effects

  In areas where there are high levels of obesity, smoking, or excess alcohol consumption theres likely to be a high occurrence of certain non communicable diseases, putting pressure on local hospitals
• Non communicable diseases national effects

  Non communicable diseases are costly at a national level because the NHS provides resources for the treatment of patients in the UK. People affected by these diseases may be unable to work and therefore this affects a countries economy.
• Non communicable disease global effect

  Non communicable diseases are very common, for example in developing countries malnutrition is very common because of lack of food. The high cost and occurrence of these diseases can hold back the development of a country.
• BMI equation


  Mass (kg) / (height (m))^2
• BMI index


  A BMI index is used as a guide to help decide whether someone is underweight, normal, overweight, or obese.

  If you eat a high fat and high sugar diet and dont do enough exercise you are likely to take more energy in than you use, which is stored as fat, meaning you are more likely to have a high BMI
• Waist to hip ratio equation

  waist circumference/ hip circumference
• Waist to hip ratio

  The higher your waist-to-hip ratio, the more weight you are likely to be carrying around your middle. It puts you at greater risk of developing obesity related health problems.
• Treatments for Cardiovascular disease: Medication

  Medication includes:

  Statins- Reduce cholesterol in blood stream (serious side effects such as liver damage)

  Anticoagulants- Make blood clots less likely to form (can cause excessive bleeding)

  Antihypertensives- Reduce blood pressure (cause side effects like headaches)
• Treatments for Cardiovascular disease: Lifestyle changes

  People with or at risk of CVD may be encouraged to eat a healthy, balanced diet, which is low in saturated fat. They may also be encouraged to exercise regularly, lose weight if necessary and stop smoking.
• Treatments for Cardiovascular disease: Surgical processes

  • Stents are tubes inserted inside arteries. They keep them open making sure blood can pass through. However over time stents can irritate the artery and make scar tissue grow.
  • If a part of a blood vessel is blocked a piece of healthy vessel taken from elsewhere can be used to bypass the blocked section.
  • Donor hearts can be used but the patient has to take drugs to stop the body rejecting it.
  • Any heart surgery has risk of bleeding, clots, and infection.