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What is a portal of entry?
Any point at which organisms can enter the body
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What are 2 protection mechanisms against pathogens for the stomach?
Stomach acid and bile; they produce hostile enviro that limit the survival of pahtogens
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Fimbriae
Short hair like appendage found exterior to the cell wall. It is used as a mechanism for staying in the host during infections.
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Capsules
A protective structure found around the outside of a bacterial cell. It can be made up of polysaccharides, polypeptides, or a combo of both.
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Adhesion
A protein or glycoprotein found on attachment pili or in capsules that helps microorganisms attach to host cells
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Mycolic Acid
A waxy substance found in the cell wall of certain bacteria, such as the genus Mycobacterium.
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What do fimbriae, capsules, adhesions, and mycolic acids do for bacteria?
They give the bacteria the advantage of proctecting itself against the defense mechanisms of the host cell
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ID 50
Infectious dose 50%. The number of organisms required for 50% of the host population to show signs of infection.
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LD 50
Lethal Dose 50%. The number of organisms required to kill 50% of the host population.
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How is virulence related to LD50 and ID 50?
- High virulence: LD50 &ID50 is low.
- Low virulence: LD50 &ID50 is high.
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Leukocidins
An exotoxin produced by many bacteria that kills white blood cells, including phagocytic cells.
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Hemolysin
An enzyme that destroys red blood cells
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Coagulase
A pathogen-produced enzyme that causes fibrin clots to form in the blood of a host. Can be used by both host and pathogen during an infection.
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Kinase
Enzymes that break down fibrin and dissolve clots. Can be used by a pathogen to overcome attempts by the host to wall of the infection, thereby ensuring spread.
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Hyaluronidase and Collagenase
Enzymes that break down connective tissue and collagen in a hsot, thereby allowing infections to spread. Ex: gas gangrene involves the destruction of connection tissue.
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What are the three types of exotoxins?
- Cytotoxins
- Neurotoxins
- Enterotoxins
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Cytotoxins
Kills cells with which they come in contact
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Neurotoxins
Interfere with neurological signal transmission
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Enterotoxins
Affect lining of digestive system
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What are symptoms of endotoxin poisening?
Chills, fever, muscle ache & weakness
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