Biology- Unit 1- Causes of Disease 0.0 / 5 ? BiologyHealth, illness and diseaseASAQA Created by: FireDwarfCreated on: 27-10-13 18:31 What is a microorganisim? Single-celled organisim thats too small to see without a microscope. 1 of 13 What is a pathogen? A microbe which causes disease 2 of 13 What is disease? Malfunctioning of the body or mind which has an adverse effect on good health. 3 of 13 What must of a microbe do to be considered a pathogen? Gain entry to host, colonise tissue of the host, resist defences of the host, cause damage to the host tissue. 4 of 13 Pathogens include? Bacteria, viruses and fungi. 5 of 13 Diffrence between infection and disease? Infection- Colonise tissues, disease- reconsiable symptoms. 6 of 13 How do microbes get into the body? Penetrating an organisims interfaces with the enviroment. An interface is a boundary between two systems (internal and enviroment). 7 of 13 Examples of interfaces? Skin breakes, gas-exchange systems, digestive system. 8 of 13 why are these places easy access? They are thin,moist, large surface area, good blood supply. 9 of 13 How do these entry points defend agianst pathogens? Mucus layer covers exchange surfaces- difficult to penatrate, enzymes break down pathogens, stomach acid. 10 of 13 How do pathogens cause disease? Damaging host tissue (breaking down membranes of the cells), Producing toxins 11 of 13 Example of how a toxin does it? eg: causes massive water loss from the intestines 12 of 13 What effects the speed of the pathogens damage? Symptoms will onset at a faster rate if the speed at which the pathogen divdies is fast. 13 of 13
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