Microbes such as bacteria, viruses, and fungi can cause disease in humans. Important scientists like Ignaz Semmelweiss, Louis Pasteur, and Joseph Lister helped discover that microbes were the cause of diseases and developed practices like hand washing and sterilization to prevent their spread. The human body also has natural defenses against microbes like skin, mucus, stomach acid, white blood cells, and the ability to develop antibodies from vaccines or previous exposures that provide protection.

1. Microbes and disease

2. microorganisms Pathogens (cause disease) Microscopic Bacteria (cause cholera, boils, MRSA,TB,typhoid) Viruses (cause warts,polio,flu,mumps,measles) Fungi (cause athletes foot, ringworm) Parasites also cause disease but these are not microorganisms ( eg fleas, worms)

3. Important scientists in this area Ignaz Semmelweiss – noticed that when doctors washed their hands fewer women died giving birth Louis Pasteur – proved germs in air caused disease Joseph Lister – developed carbolic soap and ensured surgeons and their instruments were cleaned before operations

4. Cleaning chemicals Disinfectants - for surfaces Antiseptics - for wounds/sores Why cleaning is important – good hygiene removes dirt/grease that pathogens stick to and use as a source of energy to multiply

5. Protection against disease Skin - barrier Blood clots and scabs Tears Hairs in nose filter dirt Mucus in nose and bronchi sticks to dirt/dust Acid in stomach kills microbes White blood cells – ingest microbes/make antibodies Vaccination – with weak/dead microbe to make antibodies Antibiotics – drugs to kill bacteria

6. homework Read p38-9 about drug development Find out about the drug trials that went wrong at northwick park hospital in North London Revise the whole topic ( first chapter in your text book) Practise tests next week