3.2.1 The Causes of Disease: Pathogens, Lifestyle & Disease Flashcards
Define Pathogen
Microorganisms that cause disease
Define Infection
When a pathogen enters a host cell and colonises tissues
Define Disease
Description of symptoms
Define Transmission
When pathogens are transferred from one individual to another
Define Interface
Surface or boundary linking the internal environment and the external environment
Name the 4 factors that must be present for a microorganism to be considered a pathogen
- Gain entry to a host
- Colonise tissues in host
- Resist defences of host
- Cause damage to host tissues
Name 3 natural defences the body has to prevent the entry of pathogens
- Mucous layer
- Covers exchange surfaces and forms a sticky barrier that’s difficult to penetrate
- Produce enzymes
- Breaks down pathogens
- Produce stomach acid
- Kills microorganisms
Name ways pathogens gain entry to a host
- Penetrate one of organism’s interfaces e.g. through a cut/abrasion/bite in the skin
- Gas exchange system
- Digestive system
- Reproductive system
Name the 2 main ways pathogens affect the body
- Damaging host tissues
- By producing toxins
What is a correlation?
When change in one of 2 variables is reflected by change in other variable
What do you need to prove something causes something else (e.g. smoking is the cause of lung cancer)?
causal relationship
What is a risk?
Measure of probability that damage to healthy will occur as a result of given hazard
Name the 2 elements of a risk
- Probability hazardous event will occur
- Consequences of hazardous event
Name a genetic factor that increases the risk of cancer
Specific inherited alleles
Name 2 environmental factors that increases the risk of cancer
- Exposure to radiation
- Lifestyle
