Health, disease & development of medicines

• Health


  A state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity
• Communicable diseases

  Diseases that can be spread between individuals
• Non-communicable diseases


  Diseases that can't be transmitted between individuals
• If you are affected by one disease, it could make you more susceptible to others
• Pathogens


  Organisms such as viruses, bacteria, fungi and protozoa that cause communicable diseases
• Communicable diseases

  • Cholera - bacterium - diarrhea - via contaminated water sources
  • Tuberculosis - bacterium - coughing + lung damage - through air when infected people cough
  • Malaria - protists - damage to red blood cells - mosquitoes
  • Chalara ash dieback - fungus - leaf loss + bark lesions - through air by wind
• STIs

  Sexually Transmitted Infections that are spread through sexual contact
• HIV

  The Human Immunodeficiency Virus that infects and kills white blood cells
• AIDS

  Acquired Immune Deficiency Syndrome, when the infected person's immune system deteriorates
• Chlamydia

  A sexually transmitted bacterial infection that can result in infertility
• Ways to reduce the spread of STIs

  1. Wearing a condom

  2. Screening and treatment

  3. Avoiding sexual contact
• Physical and chemical barriers

  • Skin, hair, mucus, hydrochloric acid, lysozyme (in tears)
• White blood cells


  The most important part of the immune system that patrol for pathogens
• 1. lymphocytes

  White blood cells involved in the specific immune response, producing antibodies
• Memory lymphocytes

  Cells that 'remember' a specific antigen and can mount a faster, stronger immune response
• Immunisation

  Injecting dead or inactive pathogens to trigger antibody production and memory lymphocytes
• Antibiotics

  Drugs that work by disrupting bacterial cell walls, but don't destroy viruses
• Stages in drug development

  1. Discovery

  2. Preclinical testing

  3. Clinical testing on healthy volunteers

  4. Clinical trials on patients
• Clinical trials are often double-blind, where neither the patient nor the researcher knows who is receiving the drug or placebo
• Drug testing process

  1. Tests on animals

  2. Tests on healthy human volunteers

  3. Tests on people suffering from the illness

  4. Determine optimum dose

  5. Patients randomly put into groups (new drug vs placebo)

  6. Clinical trials are blind/double-blind

  7. Drug approval by medical agency
• Non-communicable diseases

  Diseases not caused by pathogens, but have risk factors associated with them
• Lifestyle factors that may increase risk of non-communicable diseases

  • Smoking
  • Diet with too many/too few nutrients
  • Lack of exercise
  • Diet high in fat and sugar
  • Drinking too much alcohol
• Risk factors

  Things linked to an increase in likelihood of developing a disease, but don't guarantee someone will get the disease
• Risk factors can be unavoidable (e.g. age, gender) or lifestyle factors that people can change
• Smoking

  Major risk factor for cardiovascular disease
• Smoking increases heart rate, damages artery walls, and increases risk of blood clots
• Malnutrition can lead to diseases associated with nutrient deficiencies or excess
• Risk factors for cardiovascular disease

  • Smoking
  • Drinking too much alcohol
  • Lack of exercise
  • Diet high in saturated fat
• Many non-communicable diseases are caused by several different risk factors interacting, not just one factor alone
• Obesity is a risk factor for other non-communicable diseases like type 2 diabetes and cardiovascular disease
• High levels of obesity, smoking, or excess alcohol consumption in an area


  High occurrence of certain non-communicable diseases, putting pressure on local healthcare resources
• High cost and occurrence of non-communicable diseases


  Can hold back the development of a country
• Body Mass Index (BMI)


  Calculated from height and mass, used to determine if someone is underweight, normal, overweight or obese (BMI = mass (kg) / height (m)^2)
• BMI isn't always a reliable measure of obesity, as athletes with lots of muscle can have a high BMI
• Waist-to-Hip Ratio

  Calculated from waist and hip circumference, used to determine if someone is carrying too much weight around their middle (abdominal obesity)
• A high waist-to-hip ratio indicates abdominal obesity, which increases risk of obesity-related health problems
• Cardiovascular disease (CVD)

  Any disease associated with the heart and blood vessels
• Cholesterol can build up in arteries, restricting blood flow and increasing risk of heart attack or stroke
• Fatty deposits and blood clots can block blood flow to the heart or brain, causing heart attack or stroke
• Lifestyle changes to treat CVD

  • Healthy, balanced diet low in saturated fat
  • Regular exercise
  • Weight loss if necessary
  • Stopping smoking