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34 Cards in this Set
- Front
- Back
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Contact with microbe (4 results)
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1)Loss (present for short time then cleared by immune system)
2)Develop allergy 3)Becomes normal flora 4)Infiltration |
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Role of flora
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Good flora:
1 compete with pathogens 2 needed in intestine 3 source of vitamins 4 stimulate host defenses Bad flora: 1 can create biofilm 2 opportunistic infections |
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Common portals of entry for microbes (5 ways)
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1 skin
2 GI tract 3 Respiratory tract 4 Urogenital tract 5 placenta during pregnancy |
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If infection occurs 3 possible outcomes
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1 Cured by immune system
2 Carrier (asymptomatic) 3 Entrenchment in tissues (disease results after MO multiplies) |
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How pathogens attach to tissue
1 Bacteria 2 Viruses 3 Protozoans 4 Worms |
1 fimbriae, capsules, flagella, hook
2 capsid proteins, glycoprotein spikes 3 flagella or cilia 4 suckers, hooks, and barbs |
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Virulence Factors
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-contribute to and determine degree of tissue damage
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3 types of virulence factors
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1 Extracellular enzymes
2 Bacterial toxins 3 Anti-phagocytic Factors |
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Extracellular enzymes (Exoenzymes)
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Damage tissues by destroying cell components
EX: -Mucinase (amebic dysentery) -Keratinase (ringworm) -Collagenase (colstridium and certain worms) -Hyaluronidase (staph and strep) -Coaggulase (pathogenic staph) -Streptokinase (pathogenic strep) |
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Bacterial Toxins
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-Poisonous chemical products
2 types: Exotoxins Endotoxins |
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Toxigenicity
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controlled ability to produce toxins
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Toxinoses
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effects caused by toxins
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Toxemia
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toxin spread through blood stream
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Intoxication
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ingestion of toxin
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Exotoxin
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-Secreted toxin
-very potent, sometimes deadly -specific target organs -Damage cell membranes, causing lysis EX: Streptolysis (lyses RBCs) |
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Endotoxins
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-Structually part of cell
-Released during cell lysis EX:LPS (can lead to toxic shock syndrome) |
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Anti-phagocytic Factors
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Can:
1 Kill phagocytes (leukocidins) 2 Difficult to phagocytes 3 Survive inside phagocyte |
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Classic Stages of Infections
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1 Incubation period
2 Prodromal stage 3 Period of invasion (clinical period) 4 Convalescent period |
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Incubation period
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-Time between initial infection and onset of symptoms (asymptomatic)
-MO multiplying -Length depends on MO and resistance -Contagious |
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Prodromal Stage
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-Onset of vague generalized symptoms (headache, muscle aches, fatigue)
-Short period (1-2days) |
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Period of invasion
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-MO multiplies at high levels
-Greatest toxicity -Specific symptoms -Variable length |
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Convalescent Period
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-Patient respond
-Immune system overtakes pathogen -Symptoms decrease |
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Potential Outcomes of Infection (6 outcomes)
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1 Terminal (mortality)
2 Morbidity (tissue/ organ damage leading to dysfunction) 3 Recover with Immunity 4 Recover without immunity 5 Recover as asymptomatic carrier 6 Relapse |
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Patterns of Infection (5)
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1 Localized Infection
2 Systemic Infection 3 Focal Infection 4 Mixed Infection 5 Primary and Secondary Infections |
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Localized Infection
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-Microbe enters and remains confined to specific site
EX: warts, boils |
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Systemic Infection
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Spreads to several tissues via bodily fluids (blood, lymph, cerebrolspinal fluid)
-Many viral disease (AIDS) -Many bacterial diseases (Syphilis) -Some fungal infections |
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Focal Infection
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-Pathogen breaks loose from a local infection and is carried to another site
EX: TB Toxemia- toxin carried in blood away from local infection stie |
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Mixed Infection
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-Infection by multiple different microbes at same site
-Produce single disease -1st microbes breakdown tissue which allows 2nd microbe to grow EX:Gas gangreen |
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Primary & Secondary Infections
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Primary- Initial infection by one orgainism
Secondary- infection by a different microbe at a different site |
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Common Portals of Exit (5)
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1 Respiratory tract
2 Skin scales 3 Feces 4 Urogenital tract 5 Blood removal or bleeding |
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Resiratory Tract
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-Exit through saliva, mucus, sputum, nasal drainage
-via coughing, sneezing , object contact |
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Skin Scales
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-Lesions in skin and exudates
EX:HSV |
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Feces
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EX:polio
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Urogenital tract
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-Vaginal discharge or semen
Ex:STDs |
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Blood Removal or Bleeding
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-Ticks, Flies, Mosquitos
-Share needles -Blood donations -Tears in mucus membrane during sex |
