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Microbio Test 2 - 2nd half > Normal Flora > Flashcards

Normal Flora Flashcards

(114 cards)

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1
Q

How does the normal bacterial flora do for the human body?

A

Helps protect against infectious pathogens, takes up space and influences the human anatomy and physiology (immune system/vitamins) throughout life.

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2
Q

___________________ products of resident bacteria may inhibit colonization by other species.

A

Metabolic

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3
Q

What bacteria are known to inhabit the stomach?

A

Helicobacter and Lactobacillus

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4
Q

Where is the largest amount of normal flora in the body and how much is known to be present?

A

In the colon - 10^9 - 10^11/ gm

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5
Q

What bacteria is found in the small intestine?

A

Lactobacillus, Bacteroides, Fusobacterium, Staphylococcus, Streptococcus, and Enterococcus

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6
Q

What bacteria is found in the colon?

A

Fusobacterium, Eneterococcus, Bacteriodes, Bifidobacterium, Clostridium, and members of Enterobacteriaceae.

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7
Q

T/F Gut flora cannot be altered with the use of antibiotics.

A

False - Gut flora CAN be altered - can result in overgrowth by ones present in relatively low numbers

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8
Q

What bacterium can colonize the gut when it is compromised to cause psudomembranous colitis?

A

Clostridium difficile

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9
Q

What type of cells is the mouth lined with?

A

Stratified squamous epithelium

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10
Q

What tissue surrounds each tooth and crevicular fluid exudes from the crevice?

A

Gingival

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11
Q

What bathes all of the surfaces of the mouth?

A

Saliva

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12
Q

T/F - The cheek mucosa is colonized by relatively few bacteria.

A

True

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13
Q

What regions of the mouth are keratinized (glycolipid and keratin filaments)?

A

Gingivae, hard palate, and anterior doral aspect of the tongue

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14
Q

What regions of the mouth are non-keratinized (no glycolipid and little or no keratin)?

A

Areas of buccal mucosa such as the sulcus

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15
Q

The _____________ structures of the tongue provides refuge for many organisms and is highly colonized.

A

Papillary

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16
Q

The environment of the tongue has a _____ redox potential.

A

Low

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17
Q

A low redox potential allows the growth of _________ bacteria, usually G- bacteria involved in periodontal disease.

A

Anaerobic

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18
Q

What makes the tooth surface different than other parts of the body like the skin for example?

A

It has hard non-shedding surfaces (for microbial colonization)

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19
Q

T/F - The tooth structure allows accumulation of large masses of microbes and their extracellular products to produce dental plaque (biofilms).

A

True

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20
Q

What areas in the mouth allows protection from adverse conditions in the mouth and is bathed in nutritionally-rich GCF?

A

Between adjacent teeth and the gingival crevice

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21
Q

What is GCF?

A

Gingival Crevice Fluid

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22
Q

T/F - There is no difference in the smooth surface bacterial colonization whether it is on the buccal or lingual side.

A

False - There is a difference

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23
Q

Where is a great place in the mouth for microbes to colonize due to the protection from the environment?

A

Pits and fissures of the occlusal surface

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24
Q

Where does the highest incidence of caries occur?

A

Pits and fissures of occlusal surface

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25
The occlusal surface is dominated mainly by __________________ species.
Streptococci
26
When a lesion penetrates the dentine and bacterial products accumulate it leads to an _______, anaerobic condition.
Acidic
27
What types of changes occur during the progression of caries?
Nutritional sources and environmental conditions
28
T/F - In disease, the gingival crevice develops into a periodontal pocket and the production of the GCF is decreased.
False - the GCF is increased
29
What types of oral appliances act as inanimate reservoirs of bacteria and yeast?
Prosthodontic and Orthodontic appliances
30
What are the anatomical factors in the mouth aiding bacterial stagnation?
Shape of teeth, topography of teeth, mlalignment of teeth, poor quality of restorations, and non-keratinized sulcular epithelium.
31
T/F - Saliva enters the oral cavity via major and minor salivary glands.
True
32
What are the major salivary glands?
Parotid, submandibular, and sublingual
33
What are the minor salivary glands?
Lingual, labial, buccal, and palatal.
34
What are the components of saliva?
Histatins, statherins, lysozyme, proline-rich protein, anrbonic anhydrases, mucin 1 & 2, and secretory IgA.
35
What is Mucin?
Glycoproteins composed mainly of carbohydrates, which absorb tightly to the surface of teeth, becoming a component of the enamel pellicle.
36
Do mucins (glycoproteins) influence the aggregation and adhesion of bacteria to oral surfaces?
Yes - they also help in the removal of bacteria by the flow of saliva and swallowing.
37
Is mucin a part of the pellicle?
Yes
38
T/F - Mucin/ Glycoproteins aid in the prevention of acid produced by bacteria and the attacking affect on the enamel.
True
39
_________________ act as a primary role in the formation of the acquired pellicle.
Glycoproteins (mucins)
40
What acts as the primary source of nutrients for resident microflora?
Glycoproteins (mucins)
41
T/F - Glycoproteins don't interact with other components of the host defenses, just with bacteria.
False - they interact with other components of the host defenses
42
What is flow rate?
Rate of GCF flow. It may influence the caries susceptibility of a site
43
Where is the flow rate the fastest and slowest?
1. Fastest - Lower anterior lingual region | 2. Slowest - Upper anterior buccal region
44
What are the antibacterial factors of saliva?
1. mechanical washing 2. Non-specific defense factors 3. Specific defense factors 4. Buffering capacity and maintenance of pH
45
____________ saliva promotes growth of cariogenic bacteria.
Acidic
46
What are histatins?
Small MW, histidine-rich proteins which include a number of types
47
Give an example of a specific defense factor.
secretory IgA
48
What do statherins do?
Promotes remineralization by inhibiting the formation of calcium and phosphate salts - it can also have a bad effect of binding bacteria to teeth
49
What does lysozyme do?
Breaks the peptidoglycan bonds in bacterial cell walls
50
What does lactoferrin do?
Sequesters iron so bacteria can't use it for growth
51
What do proline-rich proteins do in protection?
Inhibit HIV activity most likely by interfering with the interactions between virus and host cell surfaces
52
What is a serum-like fluid that flows through the junctional epithelium of gingivae?
Cingival crevicular fluid
53
What is the flow rate of GCF in health situations and diseased situations?
Healthy - slow | Diseased - increased
54
T/F - GCF provides the crevice with specific and non-specific defense factors.
True
55
Is the GCF similar in composition to serum?
Yes
56
How does GCF influence the ecology of the crevice?
Flushes microbes out of crevice, acts as primary source of nutrients, maintains pH, provides immunological defense factors (IgM, IgG, IgA, and complement), and phagocytosis by neutrophils
57
What factors affect the growth of microorganisms in the oral cavity?
Temperature, Eh, pH, Nutrients (endogenous and exogenous), adherance antimicrobial agents and inhibitors, as well as host factors
58
What is the relatively constant temperature in the human mouth?
35-36 degrees Celsius
59
The flora in the mouth is made up by a few obligate anaerobic bacteria and most are ________________ or ______________ anaerobes.
Facultative or obligate
60
The distribution of anaerobes in the mouth will be related to the _________ _____________________ at a specific site in the mouth.
Redox potential
61
Differences in redox potential have been noted in the development of ______1______ and ________2________ disease.
1. Plaque | 2. Periodontal disease
62
How is the pH regulated on most surfaces?
By saliva
63
What is the pH range for unstimulated whole saliva?
6.75 - 7.25
64
After _____1____ consumption, the pH in plaque can fall rapidly to below ph _2_, due to acid production as a result of bacterial metabolism.
1. sugar | 2. pH=5
65
What are acid-tolerant species that colonize the mouth when the pH drops due to sugar consumption?
Streptococcus mutans and Lactobacillus species
66
The pH can become more ____1______ during the host inflammatory response in ________2_________ disease.
1. Alkaline (basic) | 2. Periodontal disease
67
What pathogen of periodontal disease is found when the pH of the mouth becomes more alkaline?
Porphyromonas gingivalis
68
What are the 2 different types of nutrients for bacteria?
Endogenous and exogenous (dietary nutrients)
69
What are endogenous nutrients?
Nutrients provided by the host
70
What is the min source of endogenous nutrients?
Saliva
71
What does nutrients does saliva contain?
amino acids, peptides, proteins, vitamins, gases and glycoproteins (also a source of sugars and amino-sugars)
72
What provides endogenous nutrients for the gingival crevice?
GCF
73
What is the main group of compounds that alter the oral ecology?
fermentable carbohydrates
74
Some fermentable carbohydrates can be converted to ______________ materials, serving as structural matrix for biofilms.
Glycocalyx
75
Thick __________ are able to accumulate on teeth, particularly at stagnant or retentive sites.
biofilms
76
What does fluoride do?
Inhibits bacterial metabolism by incorporating into the enamel causing lasting effects
77
What all is found in toothpaste?
Detergents, fluoride, metal ions, phenolic compounds and plant extracts.
78
What is one of the more active agents in mouthrinses?
Chlorhexidine
79
What agents compose mouthwash?
Chlorhexidine, thymol, menthol, and plant extracts
80
How do antibiotics get into the mouth?
Via saliva or GCF
81
What are some non-specific defense factors of the host?
physical removal by saliva, lysozyme, lactoferrin, sialoperoxidase, and histatins.
82
What is sialoperoxidase?
Can generate hypothiocyanite which inhibits glycolysis by plaque bacteria
83
What bacteria are affected by histatins?
Streptococcus mutans and Candida albicans
84
Initially, organisms are derived by ___________ contamination from mother, food, mil and water, and from the saliva of individuals in close proximity to the baby.
passive
85
What is a pioneer community?
First colonizers of the mouth
86
What are the limiting factors that change the oral environment?
Shedding of epithelial cells, chewing, saliva flow, nutrient requirements, Eh, pH, and antibacterial properties of saliva
87
T/F - During development of the pioneer community, one genus or species is usually predominant.
True - usually Streptococci
88
T/F - The metabolic activity of the pioneer community modifies the environment over time.
True - modifications include Eh or pH, exposing new receptors for attachment, and generating new nutrients.
89
Microbial succession will result in a(n) ______________ in the number of microbial groups until a stable situation is reached with a high species diversity (climax community).
increase
90
T/F - A climax community is static.
False - it is dynamic and changes occur continuously
91
What is allogenic succession?
Factors involving non-microbial influence.
92
Give two examples of allogenic succession.
1. Mutans strep and S. sanguis only appear in the mouth once teeth have erupted 2. Actinomyces species do not appear until after tooth eruption and its frequency of isolation increased with age.
93
What is autogenic succession?
Bacterial succession due to microbial factors
94
Give 2 examples of autogenic succession.
1. Aerobic and facultatively anaerobic pioneer species lower the redox potential and create conditions suitable for colonization by obligate anaerobes 2. Metabolic end products of one organism becomes a primary nutrient for a second (foodweb)
95
In children after tooth eruption, what two groups of anaerobes increases?
Spirochetes and black-pigmented bacteria
96
T/F- the oral microflora remains relatively stable.
True - microbial homeostasis
97
Wearing of dentures increases with age which promotes colonization by __________ _____________.
Candida albicans
98
Population shifts associated with aging can indicate changes in ___________________ immunity as well.
Cell-mediated
99
What is the first stage of adherence?
Initial interaction between bacterium and substrate
100
What are the bacterial and host components involved in adherence?
Bacterial - adhesins | Host - ligands
101
What are 2 ligands on the host's epithelial cells?
1. Sialic acid (S. mitis) | 2. Galactosyl ligand (beta-galactoside) - receptor is exposed when sialic acid residue is removed by neuraminidase
102
What enzyme breaks down sialic acid to expose galactosyl ligand?
neuraminidase
103
What bacteria recognize galactosyl ligand?
Actinomyces naeslundii, Fusobacterium nucleatum, and Prevotella intermedia
104
What acts as a ligand in host connective tissue?
Collagen fibers
105
What bacteria recognize collagen fibers as receptors?
Mutans Streptococci and Porphyromonas gingivalis
106
_____________ are formed by the selective adsorption of component from primarily saliva and to a lesser extent GCF.
Pellicles
107
T/F - Pellicles vary depending on the surface on which they form (hard and soft pellicles).
True
108
When do pellicles form?
As soon as a clean surface is exposed to saliva
109
How long does it take for the adsorption of molecules to reach a plateau and cease?
90-120 minutes
110
What do pellicles contain?
Proteins, lipids and glycolipids.
111
T/F - Once formed, the composition and structure of pellicles won't change, it stays the same.
False - the structures of pellicles will change and be modified.
112
How thick is an acquired enamel pellicle usually?
1 micron thick
113
What promotes adhearance to the enamel pellicle?
Acidic proline-rich proteins and statherin
114
What microbes adhere to the acquired enamel pellicle?
A. viscosus, some S. mutans strains and black-pigmented anaerobes

Microbio Test 2 - 2nd half (1 decks)

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