second line of defence

• An infection occurs when pathogens make it past the first line of defence and enter the body
• Second line of defence

  The immune system responds in some general ways that treat all pathogens equally
• General responses to infection

  • Trigger an increase in core body temperature to produce a fever
  • Trigger inflammation
• Fever


  An increase in core body temperature above 38°C, usually accompanied by shivering and sweating
• A high temperature slows down or even kills some pathogens and speeds up the processes that help the immune system deal with the threat
• Inflammation


  Painful redness and swelling around the site of an infection, caused by more blood being directed to that part of the body which contains white blood cells specialized to fight off pathogens
• Phagocytes


  White blood cells that destroy anything they don't recognize as part of the body by swallowing or engulfing it
• Pus


  When dead white blood cells build up at the site of a wound
• Snot


  Turns yellow when it contains large amounts of dead white cells, a sign that the body is fighting a respiratory infection