Causes of disease - Pathogens

Question 1

For a microorganism to be considered a pathogen it must…

Answer 1

• gain entry to host
• colonise tissues of host
• resist defenses of host
• cuase damage to host tissues

Question 2

3 examples of pathogens

Answer 2

bacteria
virus
fungi

Question 3

how do microorganisms get into the body?

Answer 3

penetrate one of organisms interfaces w/ environment

• gas-exchange system
• digestive system

Question 4

how do microorganisms get in the body via gas-exchange system?

Answer 4

airborne droplets enter body via gas exchange surfaces eg. tuberculosis

Question 5

how do microorganisms get in the body via digestive system?

Answer 5

food & water carry pathogens into stomach & intestines via mouth eg. cholera

Question 6

in what two ways do pathogens cause disease?

Answer 6

damage host tissues
- pathogens prevent tissues functioning right
- inhibit synthesis of DNA
- they break down membranes of host cells
producing toxins
- most pathogens produce them
- eg. cholera produces toxin - leads to excessive water loss from lining of intestines

Question 7

what is a transmission?

Answer 7

when a pathogen is passed from one individual to another

Question 8

what is disease?

Answer 8

a malfunction of the body or mind, has an adverse affect on good health

Question 9

what is an interface?

Answer 9

surface or boundary linking two sytems

Question 10

what are 5 natural defences prevent thatentry of pahogens?

Answer 10

Mucous layer - thick & sticky barrier - difficult to penetrate
Enzymes - break down pathognes
Stomach acid - kills micro-organisms
Plateles - barrier over skin breaks
Cillia - moves mucous moisture layer up & out of lungs