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Slide 1

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Causes of Disease
Biology Unit 1…read more

Slide 2

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Pathogens are microorganisms that cause disease; Gain entry to host,
Colonise tissues, Resist defence, Cause damage
Microorganisms get into the body by penetrating the organisms
interfaces with the environment. Common points of entry are
the digestive system (via food and water, e.g. cholera)
the gas-exchange system(via breathing as they are airborne
diseases e.g. influenza). Methods of preventing entry of pathogen
are, mucous layer that covers exchange surfaces, enzymes and HCL
in stomach which kills microorganism.
Pathogens cause disease by
Damaging host tissues: sheer number can cause damage as they can
prevent tissues working properly. Viruses inhibit synthesis of DNA,
RNA and proteins. Pathogens break down membranes.
Producing toxins: most bacterial pathogens produce toxins, e.g.
cholera/…read more

Slide 3

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Data and Disease
Although data may have a correlation it might
not mean that the two factors are causally
To describe a graph, you talk about the shape of
the graph giving figures and points. To explain
the graph you give a relationship and then
explain using knowledge why there is this
relationship and why the graph is in that
certain shape.…read more

Slide 4

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Lifestyle and Health
In respect to health risk is, a measure of the
probability that damage to health will occur as
a result of a given hazard.
Factors that affect your risk of getting cancer
are, smoking, diet, obesity, physical activity
and sunlight.…read more

Slide 5

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Bacterial infection of small intestine caused
by bacteria Vibrio Cholerae. They release
toxins which disrupts epithelial cell causing
salts and water to leave blood.
Symptoms are diarrhoea, nausea and muscle
cramps. Without treatment it is fatal due to
dehydration and massive drop in blood
It is caused by eating or drinking
contaminated water, therefore it is most
common in LEDCs.
Aim of treatment is to replace fluids and
electrolytes lost by an oral rehydration
solution also you can use antibiotics to treat
underlying infection.
There is a vaccine given as a drink but it is
only used for people going to areas of high
risk.…read more


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