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98 Cards in this Set
- Front
- Back
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Avirulent |
Refers to a microbe that lacks the ability to cause disease. |
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Pathogens |
Microbial parasites |
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Pathogens |
Disease causing microorganisms and viruses |
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Pathogenicity |
The ability of a parasite to inflict damage on the host |
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Opportunistic pathogen |
Pathogens that cause disease only in the absence of normal host resistance |
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Infection |
Situation in which a microorganism is established and growing in a host, whether or not the host is harmed |
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Infection |
The invasion of the body by a microbe |
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Disease |
Damage or injury to the host that impairs host function |
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Normal microbial flora |
Microorganisms usually found associated with human body tissue |
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birth |
Humans are colonized by microorganisms at _____ |
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pathogens |
Normal flora helps prevent colonization by ____ |
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1. competes for nutrients and thus may exclude harmful organisms |
Name 6 ways that your normal flora protects you from pathogens |
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1. moist areas: inside the nose armpit umbilicus |
What are the three microenvironments of the skin? |
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sucrose |
High concentration of ____ promote dental caries. |
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Streptococcus sobrinus |
_____ (organism) attaches to the smooth surfaces of the tooth. |
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Streptococcus mutans |
_____ (organism) attaches to the crevices of the tooth. |
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lactic acid |
What two substance are produced from sucrose metabolism by Streptococcus? |
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The skin is generally a dry and an acidic environment that does not support the growth of most microorganisms |
Why is the skin inhospitable to the growth of microbes? |
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environmental |
The skin microflora composition is influenced by ____ and _____ factors |
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Saliva contains antimicrobial enzymes |
What characteristic of the oral cavity limits microbial growth? |
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High concentrations of nutrients near surfaces in the mouth |
What characteristic of the oral cavity promotes microbial growth? |
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acidic glycoproteins |
Bacteria colonize tooth surfaces by first attaching to ______ deposited there by saliva |
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dental plaque |
Extensive growth of oral microorganisms, especially streptococci, results in a thick bacterial layer called ______ |
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anaerobic |
As plaque continues to develop, _____ bacterial species begin to grow. As dental plaque accumulates, the microorganisms produce high concentrations of ____ by fermentation that results in decalcification of the tooth enamel also called_____ |
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Streptococcus sobrinus |
The lactic acid bacteria ____ and ____ are common agents in dental caries |
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acidity |
The ______ of the stomach and the duodenum of the small intestine prevents many organisms from colonizing the GI tract |
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Vitamins (B12, K) |
Compounds produced by the intestinal flora include ____ |
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lower |
The_____ (upper/lower) respiratory tract lacks microflora in healthy individuals |
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is |
The bladder ___ (is/is not) typically sterile in both males and females |
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E. coli |
_____ and _____frequently cause urinary tract infections in women |
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acidic |
The vagina of the adult female is weakly ____ (acidic/alkaline) and contains significant amounts of _____ |
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Lactobacillus acidophilus |
________, a resident organism in the vagina, ferments the glycogen, producing lactic acid |
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Virulence |
____ is the relative ability of a pathogen to cause disease |
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LD50 (lethal dose50) |
The amount of an agent that kills 50% of the animals in a test group |
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High |
_____ (high/low) virulence pathogens show little difference in the number of cells required to kill 100% of the population as compared to 50% of the population |
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toxin |
Organism can disease by means of a ____ that inhibits host cell function or kills host cells and can travel to sites within host not inhabited by pathogen |
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Invasiveness |
___ is the ability of a pathogen to grow in host tissue at densities that inhibit host function |
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adherence |
Entry of the pathogen into the host is followed by _______ |
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adherence |
Pathogen invasion starts at the site of _____ May spread throughout the host via the circulatory or lymphatic systems |
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macromolecular interactions |
Bacteria and viruses that initiate infection often adhere specifically to epithelial cells through ____ on the surfaces of the pathogen and the host cell |
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slime layer |
Bacterial adherence can be facilitated by ____ |
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The availability of nutrients |
_____ is most important in affecting pathogen growth |
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pH |
What are some conditions in the body that affect pathogen growth? |
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Facultative aerobes deplete oxygen |
Why is the large intestine anaerobic? |
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low |
____ (low/high) virulence mutants grow faster in lab. |
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high |
____ (low/high) virulence mutants have a selective advantage and grow faster in the body. |
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antibiotics |
The use of ____ can eliminate organisms of the normal flora and allow pathogens to grow and spread. |
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Ligand (adhesin) |
Projections from the microbe or virus used for attachment. |
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Receptors |
Binding sites on the host cells. |
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Capsule |
extracellular polysaccharide used for attachment. |
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Fimbriae |
Fibrous protein projections on bacteria used for attachment |
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phase variation |
Some bacteria can change fimbriae structure in response to host defenses. This is called______. |
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Spikes |
Protein projections on a virus used for attachment. |
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M protein |
Heat and acid resistant protein that mediates the attachment of bacteria to epithelial cells. |
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collagenase |
Enzyme that destroy the basement membrane. |
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hyaluronidase |
Enzymes that degrade the glue between cells |
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Bacterial kinase |
____ dissolves clots. |
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Exotoxins |
Proteins toxins released from the pathogen cell as it grows are ____ |
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Siderophores |
____ scavenge for iron and are produced by bacteria. |
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Transferrin |
What are the ron-binding proteins produced in mammals? |
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Toxigenicity |
___ is the capacity of microorganisms to produce toxins. |
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Exotoxins |
What type of toxin is produced inside the cell and excreted to the outside. |
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Exotoxins |
(Exotoxins/Endotoxin) _______________ are protein. |
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Exotoxins |
(Exotoxins/Endotoxin) _______________ are heat labile. |
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Endotoxins |
(Exotoxins/Endotoxin) _______________ are lipopolysaccharide. |
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Endotoxins |
(Exotoxins/Endotoxin) _______________ are heat stabile. |
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Exotoxins |
(Exotoxins/Endotoxin) _______________ are potent. |
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Endotoxins |
(Exotoxins/Endotoxin) _______________ are not potent |
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Exotoxins |
(Exotoxins/Endotoxin) _______________ are found in gram negative and gram positive bacteria. |
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Endotoxins |
(Exotoxins/Endotoxin) _______________ are found in gram negatives only. |
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Exotoxins |
(Exotoxins/Endotoxin) _______________ can be made into toxoids. |
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Endotoxins |
(Exotoxins/Endotoxin) _______________ do not illicit an immune response. |
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Enterotoxin |
Toxins that damage the G.I. tract |
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necrotizing factors (toxins) |
cytotoxins that kill large amounts of cells that leads to tissue necrosis. |
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Neurotoxins |
Toxins that affect the transmission of nerve impulses. |
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Endotoxins |
Toxins that are part of the gram negative cell wall. Released upon cell death. |
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Lipopolysaccharide |
Lipid A (toxin component)+ O polysaccharide |
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Fever |
____ is stimulated by the release of interleukin-1 from macrophages. |
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phospholipases |
____ are enzymes that disrupt cell membranes. |
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Leukocidin |
A ____ kills phagocytes by damaging the plasma membrane. |
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Virulence |
___ is the measure of pathogenicity |
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Moist |
____ areas of the skin are readily colonized by gram-positive bacteria and other normal flora of the skin |
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Attenuation |
The decrease or loss of virulence is _____ |
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Cytolytic toxins |
What are the three categories of exotoxins? |
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Cytolytic |
______ toxins work by degrading cytoplasmic membrane integrity, causing cell lysis and death |
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hemolysins |
Toxins that lyse red blood cells are called _____ |
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Interleukin-1 |
____ is an endogenous pyrogen. |
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Shock |
What conditions are stimulated by the release of cytokines from macrophages that have been exposed to lipopolysaccharide? |
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B subunit |
Which subunit of an A-B toxin works by binding to host cell receptor |
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A subunit |
___ is the damaging agent of an A-B toxin |
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B subunit |
Which subunit of an A-B toxin transfers the other subunit across the cell membrane? |
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Entertoxins |
___ are toxins that generally cause massive secretion of fluid into the intestinal lumen, resulting in vomiting and diarrhea |
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Endotoxin |
____ is the lipopolysaccharide portion of the cell envelope of certain gram-negative bacteria. |
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compromised |
A host is ____ if one or more resistance mechanisms are inactive |
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1 Intact skin-physical barrier |
List some physical components of the first line of defense |
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Sebaceous Oil |
What are some of the chemical aspects of the first line of defense? |
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Innate resistance |
__ are defenses against any pathogen and are present at birth |
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Age |
What are some prediposing factors? |
