Pathogens and Semmelweiss

Pathogens and Semmelweiss

1. Pathogens

   • Bacteria
     • Small living cells
     • 1/100th the size of body cells
     • Reproduce rapidly
     • Make you feel ill
       • Damaging your cells
       • Producing toxins (poisons)
   • Viruses
     • Not cells
     • 1/100th the size of a bacterium
     • Replicate themselves by invading your cells
       • Use cells machinery to produce copies
         • Burst and releasing new viruses
     • Cell damage makes you feel ill

2. Defense system

   • Platelets
     • Help blood clot quickly to seal wounds
     • Small fragments of cells
     • If blood contains low numbers of platelets it will clot slowly
   • If it gets through immune system kicks in

3. Immune system

   • White blood cells
     • Travel around the blood
     • Patrol for microbes
     • Invading a microbe
       • Consuming them
         • Engulf foreign cells and digest them
       • Producing antibodies
         • Every invading cell has unique molecules called antigens on its surface
           • Starts producing proteins called antibodies when they come across a foreign antigen they lock onto and kill invading cells- specific to the type of antigen
             • Produces antibodies rapidly and carries them around the body to kill similar bacteria or viruses
               • If infected again the white blood cells will produce antibodies and become naturally immune to the pathogen
       • Producing antitoxins
         • Counteract toxins produced by invading bacteria

4. Semmelweiss

   • Women were dying in huge numbers after childbirth from a disease called puerperal fever
     • He believed it was doctors spreading the disease as their hands were unwashed from when they treated other patients
       • Doctors were made to wash their hands in an antiseptic solution and the death rate dropped by 10%
         • Antiseptic solution killed the bacteria on doctors' hands. There was no proof of this so his method was dropped when he left the hospital and death rates rose again
           • Nowadays we have basic hygiene, education and new drugs to control disease