Health 2.61-2.69

• Health


  Free from communicable and non-communicable diseases
• Non-communicable disease


  Cannot be passed on
• 50% of all deaths in humans are from non-communicable diseases
• Cost of ill health in society

  • Unhealthy people may not be able to work and require care
  • The NHS spends billions of pounds per year treating and looking after sick people
  • Most of the NHS budget is spent on medicine and the salaries of doctors and nurses
• HIV


  Virus spread through exchange of body fluids during sex and infected blood
• How to control HIV

  1. No cure

  2. Using condoms will reduce infection

  3. Addicts not sharing needles
• Colds/Flu


  Virus spread through air, cured by flu vaccination
• HPV


  Virus spread through sexual contact, cured by vaccines for 12-13 year old girls against cervical cancer
• Salmonella


  Bacterium spread through contaminated food, cured by thoroughly cooking food and antibiotics
• Tuberculosis


  Bacterium spread through air, cured by BCG vaccination or antibiotics
• Chlamydia


  Bacteria spread through sexual contact, reduced by condoms or antibiotics
• Athlete's foot


  Fungus spread through contact, cured by avoiding direct contact in likely present areas
• Potato Blight


  Fungus spread through air spores in warm, humid conditions, cured by crop rotation and fungicide spraying
• Aseptic Techniques


  1. Ensure microorganisms being investigated do not escape or become contaminated

  2. Prevent growth of unwanted, pathogenic microorganisms
• Examples of Aseptic Techniques

  • No eating or drinking in the lab
  • Using sterile loops when transferring cultures
  • Flaming culture bottle necks to prevent contamination
  • Sterilising or disposing of all used equipment
  • Washing hands thoroughly
• Pathogen


  Something that can make you sick
• Nose defence


  • Hair
  • Mucous Membranes
• Skin defence


  • pH
  • Oils
  • Barrier - if barrier breaks then blood clots and scabs
• Antigens


  Chemicals on the surface of invading pathogens that cause special white blood cells called lymphocytes to react
• Lymphocyte reaction


  1. Produce Chemicals called Antibodies

  2. Stimulate Phagocytes to react

  3. Stimulate the production of Memory Lymphocytes which remember how to fight antigen
• Antigens


  A protein on the surface of a pathogenic microorganism that stimulates the production of specific complementary antibodies by Lymphocytes
• Phagocytes


  They engulf and digest by enzymes
• Role of antibodies


  • They have a specific, complementary shape to an antigen
  • These shapes cause them to clump together on microorganisms' surface
  • Once clumped together they are immobilised=less likely to spread and more easily destroyed by phagocytes
• Response to first infections

  1. 1 Type of bacteria enters the body

  2. These bacteria have antigens on their surface. These are foreign proteins that trigger the body's immune response

  3. White Blood Cells have Lymphocytes that produce Antibodies

  4. These antibodies attach to the foreign proteins on the bacteria's surface

  5. This causes clumping which stops bacteria from moving and reproducing

  6. Phagocytes engulf and digest bacteria
• Primary response


  The body's initial response to combat the first infection, during which it also makes memory lymphocytes
• Secondary response


  After the primary response, if the same microorganism is encountered again, memory lymphocytes produce high numbers of the correct antibody very quickly to prevent the person getting sick again
• How to become immune

  1. High enough levels of antibodies

  2. Capacity to produce high enough
• Active Immunity


  When the body is activated and produces the antibodies needed to fight an infection, either naturally or through vaccines
• Characteristics of Active Immunity

  • Slow acting
  • Provides long-lasting protection
• Passive Immunity


  When ready-made antibodies, from another source, are introduced to the body, e.g. breastfeeding, anti-venom
• Characteristics of Passive Immunity

  • Fast acting
  • Only lasts a short period of time
• Plant defense mechanism categories

  • Structural e.g. waxy cuticle
  • Chemical e.g. thick cell walls
• Antibiotics

  Chemicals produced by fungi that kill or prevent the growth of bacteria
• While investigating bacteria in the 1920s, Alexander Fleming noticed that a fungus (a mould) had contaminated one of his bacterial cultures and concluded that an antibacterial substance was diffusing out of the fungus, preventing the growth of the bacteria
• In the 1940s, Florey and Chain were able to isolate a pure form of penicillin and begin large-scale production
• How Penicillin is commercially made


  1. The fungi that make penicillin are grown in large biodigesters or fermenters that create the perfect conditions for fungal growth

  2. The penicillin is then extracted, purified and packaged in a process known as downstreaming
• Preclinical trials


  1. Testing a drug in a lab on cells and tissues-in-vitro testing

  2. Testing drugs on animals

  3. Computer modeling
• Purpose of preclinical trials


  • Check if the drug is poisonous or harmful
  • Check how effective the drug is
• Clinical Trials


  1. Initially, small groups of healthy, human volunteers are used

  2. Participants are sometimes paid but some are willing to help with medical research for free

  3. Patients who can potentially benefit from the drug can also volunteer
• Purpose of Clinical Trials

  To determine the correct dosage required. If successful, the drug can be licensed for use.