Download Mechanisms of Disease - Woodstown

Mechanisms of Disease
Disturbances to homeostasis and the
body’s responses
Disease Mechanisms
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Genetic mutations
Pathogenic organisms and particles
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parasites
Tumors and cancer
Physical and chemical agents
Malnutrition
Autoimmunity
Inflammation
Degeneration
Risk Factors
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Genetic factors
Age
Lifestyle
Stress
Environmental factors
Preexisting conditions
Many risk factors overlap and can be avoided.
Pathogenic particles
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Viruses –
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small,nonliving particle,
capsid and nucleic acid
can not reproduce on own
Symptoms can be slow to appear
Ex. SARS, West Nile, HIV (table 5-1)
Prion – pathogenic protein molecule, convert
normal proteins to abnormal ex. Mad cow
Bacteria- Pathogenic organism
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Prokaryotic
Produce disease by:
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secreting toxins
parasitic in human cells
form colonies to disrupt normal function
Classified by
Function: aerobic/anaerobic
 Staining properties: gram -, gram +
 Size and shape – coccus, spirilla, bacillus
 Table 5-2 for examples
Spores – formed under adverse conditions
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Fungus
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Fungus
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Heterotrophic, parasitic
Molds, mildew
Often resists treatment
Ex. Athelete’s foot, yeast infections (table 5-3)
Protozoa
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Unicellular, eukaryotic organisms
Larger than bacteria
Major groups (classified by locomotion)
Amoebas
 Flagellates
 Ciliates
 Sporozoa (usually 2 hosts and 2 life cycles)
Table 5-4 for examples
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Pathogenic Animals - metazoa
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Large, multicellular
Major groups
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Nematodes – roundworms, human tissue
Platyhelminths – flatworms and flukes
Arthropods – mites, ticks, lice and fleas, wasps,
mosquitoes, spiders
Table 5-5 for examples