Science Last Outcomes

• Contagious


  An infectious disease that can pass from one person to another
• Ways pathogens can pass from person to person

  • Shaking hands
  • Sharing drinks
  • Breathing in saliva when someone infected coughs or sneezes
• Non-contagious


  A medical condition that cannot be spread from person to person
• For a disease to be infectious, it needs to be caused by a pathogen
• Transmission methods for infectious diseases

  • Eating contaminated food or drinking contaminated water
  • Breathing in infected saliva droplets after someone coughs or sneezes
  • Exchanging bodily fluids, such as blood or saliva
  • By a vector, such as a mosquito or tick
• Infectious diseases


  • Deadliness or virulence (percentage of infected people that die from it)
  • Contagiousness (how easily it spreads)
• Ways to prevent the spread of disease

  • Frequently wash your hands with soap
  • Avoid touching nose, eyes or mouth
  • Do not share cutlery with other people
  • Quarantine yourself if you are feeling unwell
• Epidemiologist


  A person who studies the branch of medicine which deals with the incidence, distribution and possible control of diseases
• Epidemic


  A more widespread outbreak that may affect the entire nation
• Pandemic


  An epidemic that is affecting the entire world
• Endemic


  An outbreak confined to a particular geographical area
• Direct transmission


  Physical contact between the infected person and the other person (skin-to-skin, herpes type 1)
• Indirect transmission


  No direct skin-to-skin contact (food-borne, salmonella)
• The innate immune system includes physical, chemical and cellular defences against pathogens
• The main purpose of the innate system is to immediately prevent the entry into the body and the spread of the pathogen
• First line of defence against pathogens

  • Skin
  • Tears, saliva, mucus
  • Stomach acid
  • Cilia
  • Urine flow
• Physical barriers


  Stop pathogens from entering the body
• Chemical barriers


  Kill pathogens before they can enter the body
• Second line of defence against infection

  • Fever
  • Inflammation
  • Phagocytes
• Fever


  An increase in body temperature above 38°C that slows down or kills some pathogens and speeds up processes that help the immune system
• Inflammation


  Painful redness and swelling around the site of the infection due to increased blood flow containing white blood cells
• Phagocytes


  White blood cells that destroy anything they don't recognise by engulfing and destroying pathogens
• The adaptive immune system changes in response to exposure to pathogens throughout our life
• Components of the adaptive immune system

  • Helper T cells
  • B cells
  • Memory cells
• Helper T cells


  Activate B cells when exposed to pathogens
• B cells


  Make antibodies that are specific to the antigen found on the invading pathogen
• Memory cells


  Retain a memory of how to make the antibodies
• Antigen


  Large molecules on surfaces of foreign bodies such as viruses, fungi, bacteria, toxins, chemicals that trigger an immune response
• Antibody


  Proteins produced by B cells that bind to specific antigens, labelling them for destruction
• Antibodies bind onto markers on pathogens to identify them, each pathogen has unique markers, can only bind to antibodies with matching shapes
• After the infection is defeated, some of the B cells remain in the blood as memory cells, along with leftover antibodies