health and disease

• Health


  The complete social, physical and mental well-being of a person
• Disease


  Any change in the normal function of a part of the body
• Types of diseases


  • Communicable
  • Non-communicable
• Communicable diseases


  Can be spread from person to person
• Non-communicable diseases


  Cannot be spread from person to person, mainly caused by lifestyle or genetics
• Causes of communicable diseases

  • Pathogens (microorganisms that can cause disease)
  • Cholera (bacteria, spread through water)
  • Tuberculosis (bacteria, airborne)
  • Chlora diet ashbach (fungal disease, airborne, affects plants)
  • Malaria (protist, spread by vectors like mosquitoes)
  • Helicobacter (bacteria, spread through touch)
  • HIV (virus, spread through bodily fluids)
  • Chlamydia (bacteria, spread through sexual contact)
• Viruses


  Pathogens made up of genetic material (DNA or RNA) surrounded by a protein coat, cannot reproduce themselves and must use living cells to replicate
• Barriers to pathogens in the human body

  • Physical barriers (skin, mucus, cilia)
  • Chemical barriers (stomach acid, lysozyme)
• Components of the immune system

  • Phagocytes (engulf pathogens)
  • Lymphocytes (produce antibodies)
• Antigens


  Flags on cells that identify them as belonging to the body
• Antibodies


  Produced by lymphocytes, have a specific shape to bind to antigens and destroy pathogens
• Vaccines


  Contain dead or weakened pathogens to stimulate an immune response
• Drug development process


  Pre-clinical trials

  1. test on human tissue
  2. then animals

  Clinical trials

  3. test on healthy humans

  4. then ill humans

  5. then large-scale
• Efficacy


  How well a drug works
• Toxicity


  Side effects of a drug
• Causes of non-communicable diseases

  • Lifestyle choices (obesity, smoking)
  • Genetics
• BMI (Body Mass Index)


  Measure of obesity calculated as mass divided by height squared
• Waist to hip ratio

  Measure of abdominal obesity calculated as waist measurement divided by hip measurement
• Smoking


  Leads to fatty buildup in arteries, restricting blood flow and causing cardiovascular disease
• Cardiovascular disease (CVD)


  Problems with the heart or blood vessels
• Treatments for CVD


  • Stents (open up arteries)
  • Statins (medication that lower cholesterol)
• when making a new drug you want to: maximise efficacy and minimise toxicity.
• Physical barriers 


  • skin - strongest barrier, stops any pathogen from getting into our body because it is so thick. when the skin is cut or damaged, pathogens can get in.
  • mucus - sticky, thick substance that traps substances in the back of our throat.
  • cilia - moves pathogen to stomach to die.
• Chemical barriers


  stomach acid - has a low PH, stomach acids kill any pathogens in our food

  lysozyme - enzyme that breaks down pathogens
• Another word for stomach acid

  Hydrochloric acid