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11 Cards in this Set

  • Front
  • Back
what is a pathogen?
- a term that means anything that causes a disease
- produce toxins
- common types :
Bacteria, viruses, Fungi, Prodists, Rickettsiac
- viruses and certain bacteri cause diseases by destroying cells
the toxins that pathogens produce?
- chemical substances: are poisonous to normal cells
- neurotoxins: substances that disrupt the transmission of nerve impulses

example: bacteria associated w/ botulism
- neurotoxin that cuases double vision and severe pain
invertebrates cause diseases by burrowing into tissues
- muslce or intestinal tissue
- cause pain or interfere w/ normal tissue functions
four main mechanisms of transmission of pathogens
1. air: in spores or cysts or in droplets
2. water: wastes containing pathogens released into water used for other purposes such as drinking or bathing
3. human contact:direct touching or indirectly by touching an object
4. arhropod vectors: lice, mosquitoes, ticks and fleas carry the pathogens
what is an infectious disease?
a disease caused by the entrance of a pathogen into a host.
- disease can be spread
koch's postualtes : the steps
1. isolate the organism suspeted of causing the disease
2. grow the organism in a pur laboratory culture
3. inject a healthy animal w/ the cultured pathogen. observe whether the healthy animal contracts the disease
4. in the animal contracts the disease, isolate the organism that caused it. compare this organism w/ one from step 1.

- enable scientists to determine whether a particular pathogen causes a disease
- still used today in the study of infectious disease
common disease and their causes.
1. athlete's foot: fungus : contact w/ contanimated surfaces such as shower floors
2. common cold: any of 100 viruses : close contact w/ infected person; air bourne spread of virus
3. hepatitis A: virus : person to person contact;eating contanimated food or water
4.influenza: any of 100 viruses : person to person contact; contact w/ contanimated objects
5. measles (rubeola): virus : contact w/ infected saliva mucus; air bourne spread of virus
6. pneumonia: virus or bacteria : contact w/ infected saliva mucus
what is the definition of a disease? what are agents that produce diseases and what are they also known as?
is any change, other than an injury that disrupts the normal function of the body

agents that produce diseases (a.k.a. pathogens): bacteria, viruses and fungi

thousands years ago people thought diseases were caused by: curses, evil spirits, right vapors
observations by koch and pasteur led them to conclude that infectious diseases were caused by what?name of theory?
K. and P. concluded that infectious diseases caused by microorganisms of different types, commonly called germs. theory is called the germ theory of disease
why do pathogens cause diseases?
they sometimes destroy cells as they grow or release toxins that harm the organism. others can block the flow of blood, remove nutrients from the digestive system, disrupt other bodily functions
chart of agent of disease.
1. viruses : tiny particles that invade and replicate within living cells
example: common cold, warts influenza, smallpox
2. bacteria : some harmless to humans; others either break down tissues of infected organism for food or by releasing toxins that harm the body
example: strep, anthrax, diphtheria, botulism
3. protists: causes the single most damaging disease for humans
example: plasmodian, trypanosoma, etamoeba
4. worms: common in tropical regions
example: schistosoma, tapeworms, hookworms
5. fungi: most are harmless; some cause serious problems
example: tinea - causes athlete's foot, ringworm