Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DEN 2027 - Disease Mechanisms > Oral Ecology 1 > Flashcards

Oral Ecology 1 Flashcards

1
Q

What is oral ecology?

A

The study of all the relationships between microorganisms and the mouth (their environment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the oral microbiome?

A

Multi-species community of microbes in the oral cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What 2 things can the environment impact in terms of microorganisms?

A
  1. Type of microorganism present

2. Number of microorganism present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name an advantage of using a culture to determine microbial composition of the oral ecosystem

A

Cultivated bacteria can be used for metabolic studies and antimicrobial sensitivity tests

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Name 4 disadvantages of using a culture to determine microbial composition of the oral ecosystem

A
  1. Only 50% of bacteria can be grown
  2. Biased towards predominant organisms
  3. Slow
  4. Labour intensive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Name 2 advantages of using a molecular sample to determine microbial composition of the oral ecosystem

A
  1. Relatively little bias

2. Rapid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name 3 disadvantages of using a molecular sample to determine microbial composition of the oral ecosystem

A
  1. Properties have to be inferred from sequence data
  2. Limited data available
  3. Antimicrobial sensitivity testing not possible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Name 3 types of bacteria present in the mouth

A
  1. Indigenous species
  2. Supplemental species
  3. Transient flora
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What disease is porphyromonas gingivalis associated with?

A

Periodontal disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What disease is streptococcus mutans associated with?

A

Dental caries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is characteristic of indigenous species of bacteria in the mouth?

A

Present in stable relationship with host and do not compromise the survival of the host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is characteristic of supplemental species of bacteria in the mouth?

A

Present in small numbers but if environment changes their numbers can increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give 2 examples of supplemental species

A
  1. Streptococcus mutans

2. Porphyromonas gingivalis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is characteristic of transient flora in the mouth?

A

Pass through the mouth but do not become established

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give an example of transient flora

A

E. coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Name 2 beneficial effects of normal flora

A
  1. Colonisation resistance to more virulent bacteria

2. May release some nutrients from food (more important in animals e.g. cattle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain 4 general mechanisms of disruption of the normal flora

A
  1. Suppression by antimicrobial agents
  2. Changes in general health or immunological status
  3. Hormonal changes e.g. pregnancy
  4. Local trauma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Explain 5 oral cavtiy specific mechanisms of disruption of the normal flora

A
  1. Changes in diet
  2. Reduction in salivary secretion
  3. Dental disease
  4. Dental treatment
  5. Changes in oral hygiene regime
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are 5 characteristics of the habitat provided for microorganisms by lips, cheeks and palate?

A
  1. Biomass restricted by desquamation
  2. Surfaces may have specialized host cell types
  3. Saliva has major influence
  4. Microflora has low diversity
  5. Facultative anaerobes present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are 4 characteristics of the habitat provided for microorganisms by tongue?

A
  1. Biomass restricted by desquamation
  2. Highly papillated
  3. Acts as reservoir for obligate anaerobes
  4. Diverse microflora
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are 2 characteristics of the habitat provided for microorganisms by teeth?

A
  1. Non-shedding surface allows large masses of microbes to accumulate
  2. Distinct surface support distinct microflora due to intrinsic biological properties e.g. fissure, smooth surfaces, gingival crevice etc
  3. Host many anaerobes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where in the oral cavity is the only non-epithelial covered surface in the body?

A

Junction between teeth and gum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Name the main microorganism found on the lips, cheeks and palate

A

Streptococcus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Name 5 microorganisms found on the tongue

A
  1. Streptococcus
  2. Actinomyces
  3. Rothia
  4. Neisseria
  5. Some gram negative anaerobes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Name 6 microorganisms found on the teeth

A
  1. Streptococcus
  2. Actinomyces
  3. Veillonella
  4. Fusobacterium
  5. Prevotella
  6. Treponema
26
Q

What does the acquisition of resident oral microflora involve?

A

Interaction between adhesins on microbial cell surface and receptors on the host surface

27
Q

What is the function of desquamation?

A

Ensure microbial load is light on mucosal surfaces

28
Q

What forms an acquired pellicle on the teeth?

A

A wide range of receptors mainly from salivary proteins are absorbed onto the teeth

29
Q

What is the function of an acquired pellicle on the teeth?

A

Increases potential for diversity in terms of microbial colonisation

30
Q

What are accumulations of microorganisms on the teeth termed?

A

Dental plaque

31
Q

What is a biofilm?

A

The term used to describe communities of microorganisms attached to a surface

32
Q

What is an important feature of a biofilm?

A

Microbial cells with different metabolic requirements can exist successfully in these communities

33
Q

Name 4 key advantages of biofilms to microbes

A
  1. Survival and protection
  2. Assists adhesion
  3. Extends habitat range
  4. Increases resistance to antibiotics / antimicrobial agents
34
Q

Why does a biofilm aid adhesion?

A

Microorganisms which become attached may express receptors which allow other microorganisms to attach

35
Q

Why does a biofilm extend habitat range for microorganisms?

A

Microorganisms tend to work together i.e. aerobes colonize, then facultative anaerobes enter and when oxygen used up, obligative anaerobes enter

36
Q

How are microorganisms in a biofilm organised?

A

Spatially organised into a 3D structure, enclosed in a matrix of extracellular polymeric substance (EPS) such as long chain polysaccharides

37
Q

Name an example of a long chain polysaccharide used in biofilms

A

Glucan

38
Q

Name 2 functions of glucan in biofilms, other than being the EPS

A
  1. Aids bacterial adhesion

2. Acts as source of carbon when dietary supplies are limited

39
Q

Why do biofilms have open structures?

A

Allows them to contain channels which facilitate the passage of nutrients and sometimes oxygen

40
Q

Name 5 differences between planktonic microorganisms and biofilm organisms

A
  1. Freely suspended
  2. Can be single or multi-species but very large distances between cells
  3. No spatial organisation, although there can be some co-aggregation
  4. Limited cell to cell communication
  5. No protection from antimicrobials so immune system can easily remove cells

(All with respect to planktonic cells)

41
Q

Name the 5 stages of development of a biofilm

A
  1. Initial attachment
  2. Irreversible attachment
  3. Maturation I
  4. Maturation II
  5. Dispersion
42
Q

What occurs during stage 5 of biofilm development?

A

Climax community and optimal size is reached so external organisms become planktonic, leave to colonise elsewhere, become quiescent or die

43
Q

How is initial attachment achieved during the formation of a biofilm?

A

Weak attraction and binding by non-specific forces (Van der Waals / Ionic) to the surface

44
Q

How is irreversible attachment achieved during the formation of a biofilm?

A

Stronger, ligand-receptor binding to the surface

45
Q

What 4 things can mediate irreversible attachment of a biofilm?

A
  1. Adhesins
  2. Surface fibrils
  3. Pili
  4. Flagellae
46
Q

How is maturation I achieved during the formation of a biofilm?

A

Establishment of microcolonies and recruitment of additional microorganisms

47
Q

How is maturation II achieved during the formation of a biofilm?

A

Growth of biofilm microcolonies by recruitment of additional microorganisms

48
Q

In what 3 ways can microorganisms be recruited from during both maturation phases of biofilm development?

A
  1. Environment
  2. Multiplication from within
  3. Production of EPS (only maturation II)
49
Q

Name 5 ways biofilms are more resistant to antimicrobial therapy

A
  1. Reduce penetration of antimicrobials
  2. Multi-drug efflux pumps can sequester drugs
  3. Reduced metabolic activity of microorganisms
  4. Resistant cells can remain viable so re-establish biofilm post treatment
  5. Natural resistance e.g. mutations and stress responses
50
Q

What are the 3 basic steps in dental plaque formation?

A
  • Clean tooth surface
  • Salivary glycoprotein coat (pellicle)
  • Bacterial colonisation
51
Q

What disease is supragingival plaque associated with?

A

Dental caries

52
Q

What disease is subgingival plaque associated with?

A

Periodontal disease

53
Q

What is the main bacteria which predominate the initial formation of plaque?

A

Gram positive cocci, in particular streptococcus oralis

54
Q

How is the dental pellicle formed?

A

Selective absorption of negative charged salivary glycoproteins preventing the continuous deposition of calcium phosphate

55
Q

What is the main role of the pellicle?

A

Protect the enamel against abrasion and attrition and also serving as a diffusion barrier

56
Q

How long does it take for dental plaque to become fully mature?

A

2 weeks

57
Q

Once plaque thickens, what microorganism begins to dominate?

A

Actinomyces

58
Q

What microorganism tends to increase as the plaque becomes more subgingival?

A

Veillonella

59
Q

What occurs when dental plaque becomes calcified?

A

It becomes calculus

60
Q

Where are the 2 most common locations in the mouth of calculus to be found?

A
  1. Lingual surfaces of lower anterior teeth

2. Buccal surfaces of upper first molars

DEN 2027 - Disease Mechanisms (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions