#**causes of disease**
1)what they are,2) how they get into the body & 3) how they cause disease
1) pathogen: any micro-organism that causes disease. (pathogens include bacteria, viruses & fungi)
2) gas exchange system: many pathogens enter the body through the gas exchange surfaces. pathogens that cause influenza, tuberculosis & bronchitis infect in this way.
2) digestive system: food & water may carry pathogens into the stomach & intestines via the mouth. cholera, typhoid & dysentery pathogens enter by this means.
3) By damaging host tissue: numbers can cause damage, some break down the membranes, viruses can take over the DNA and RNA of hosts.
3) by producing toxins: pathogens can produce toxins. cholera can produce toxins that lead to excessive water loss from the lining of the intestines.
1) risk, 2) lifestyle choice and cancer, 3) lifestyle choice and coronary heart disease, 4) reducing risk of cancer and CHD