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15 Cards in this Set
- Front
- Back
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why do microorganisms like humans so much?
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* constant source of nutrients
* constant source of moisture * stable pH * stable temerature * extensive surface area |
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Endogenous infection
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occurs when normal flora is introduced into a site that was previously sterile.
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sterile body sites
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blood, urine, CSF, liver, kidneys, brain, muscles, bone, ovaries/testes
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non-sterile body sites
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skin, upper respiratory tract, gastrointestinal tract, vagina, mucous membranes.
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skin and mucous secretions
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* spread in skin is slow, unless aided by scratching.
* moisture aids spreadon skin and mucous membranes. * sneezing and coughing redistribute microorganisms on the mucous membranes (and into the enviroment) |
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lymph vessels
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* microorganisms or their products can use the lymphatic system as a highway for transpotation around the body.
* some organisms multiply in the lymph nodes. * swollen and tender lymph nodes are OFTEN the result of host-microbial interactions. |
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blood
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* an excellent culture media and is often used in the lab to grow a number of organisms.
* some organisms can live and multiply inside red blood cells. * some organisms prefer white blood cells. |
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Cerbral Spinal Fluid - CSF
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* also an excellent culture media.
* infections that reach the CSF will quickly affect the brain and spinal cord and must be treated aggressively. |
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nerve tissue
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* rabies virus and some microbial toxins affect nerve tissue.
* other nerves harbor latent viruses. ( chickenpox - shingles and other Herpesviridae) |
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muscle tissue
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* Certain protozoa and viruses are attracted to muscle tissue.
- Trichinella spiralis - Trypanosoma cruzi |
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Peritoneum
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membrane lining the abdominal cavity, organisms entering can spread to many organs.
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Pleura
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membrane lining the chest cavity, organisms entering can spread along the surface of the lungs.
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pathogen
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a microbe whose relationship with its host is parasitic and results in infection and disease.
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true pathogen
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capable of causing disease in healthy persons with normal immune defenses.
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opportunistic pathogen
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cause disease when the host's defenses are compromised.
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