Pathogens cause infectious disease.
- A pathogen is any organism that causes disease
- including microorganisms and larger organisms like tapeworms
- including bacteria some fungi and all viruses
Pathogens can pentrate an organisms interface with the enviroment
pathogens need to enter the body to cause disease.
- GAS EXCHANGE- air can contain pathogens, most will be trapped in the mucus and be beated out by cillia to trachea and moiuth but some wil reach alveoli and invade cells.
- SKIN - if you damage you skin pathogens on the surface can enter your blood stream. Blood clots can prevent pathogens from entering, some may enter before clot forms however..
- DIGESTIVE SYSTEM - food and drink may contain pathogens. Most will be killed by the acidic conditions of the stomach , but some may live and invade the gut wall and cause disease..
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How do pathogens damage cells
PATHOGENS CAUSE DISEASE BY PRODUCING TOXINS AND DAMAGING CELLS
- PRODUCTION OF TOXINS- many bacteria release toxins in to the body. for example: Tetanus produces a toxin that blocks the function of certain nerve cells- causing spasms
- CELL DAMAGE- pathogens can physically damage host cells by:
- RUPTURING them to release nutrients ( protiens) inside them
- BREAKING DOWN nutrients inside the cell for own use ( starving and nearly killing the cell
- REPLICATING inside the cells and bursting them with they are release ( like viruses)
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