CMS/Microbiology

Question 1

What are the stages in formation of a clot?

Answer 1

Vasoconstriction

Platelet plug formation

Fibrin clot formation (coagulation)

Question 2

How does aspirin/warfarin/heparin affect clot formation?

Answer 2

aspirin- Reduces platelet aggregation

Warfarin- inhibits vit k dependent clotting factors 2, 7, 9, 10

Heparin- inactivates thrombin preventing fibrin formation (and clotting factors 5, 8 and platelets)

Question 3

Why are aspirin and clopidogrel used together?

Answer 3

As they can be combined and have synergistic/additive effect

Question 4

What pattern does Von Willebrands disease follow?

Answer 4

T1/2- autosomal dominant
T3- autosomal recessive

Question 5

What causes effect of VWD on bleeding?

Answer 5

Deficiency of VWF and reduction of Factor 8

Question 6

What is a biofilm?

Answer 6

Complex aggravation of microorganisms encased in highly hydrated matrix of exopolysaccharide excreted by microorganisms

Question 7

What are the stages in biofilm development?

Answer 7

Adhesion
Colonisation
Accumulation
Complex community
Dispersal

Question 8

What are the methods of identifying organisms?

Answer 8

Aspirate

Swab

Rinse

Biopsy

Question 9

What are the virulence factors of P.Gingivalis?

Answer 9

Fimbriae- adhesion/invasion

LPS

Capsular polysaccharides

Proteases- collagenase, phospholipase, fibrinolysin,
gingpains

Tissue toxic metabolic products- ammonia, fatty acids

Question 10

What are the virulence factors of Candida albicans?

Answer 10

Germ tube formation

Adhesins

Metabolic acids

Extracellular enzymes

Switching mechanism

Question 11

What are the virulence factors of S.Mutans?

Answer 11

EPS/sucrose metabolism

Attachment mechanisms- gtf, ftf, glucan binding

Adhesins- SpaP

Acid tolerance- F1-F0 ATPase

Question 12

What is difference between solids and liquids with regards to oral seal?

Answer 12

Posterior oral seal is required for ingestion of liquids
(No stage 2 transport)
-> During processing of solid foods the mouth is continuous with oro-pharynx

Question 13

What is ingestion?

Answer 13

Movement of food from external environment into mouth

Question 14

What is Stage 1 transport?

Answer 14

Food is gathered in tongue tip
-> tongue retracts pulling material back to posterior teeth
-> hyoid bone and narrowing of oesophagus occurs

Question 15

What is mechanical processing?

Answer 15

Food is mixed with saliva to allow swallowing

Food is masticated by molars and premolars

Bolus is squashed against hard palate and tongue

Question 16

What is stage 2 transport?

Answer 16

Bolus moves anterior posteriorly by squeeze-back
-> Solid foods move through fauces to pharyngeal surfaces of tongue

Question 17

What is swallowing?

Answer 17

​Involuntary movements push bolus through pharynx to oesophagus

UOS opens then epiglottis closes to prevent backflow

Peristalsis occurs to move bolus toward stomach

Question 18

What are the stages in tooth development?

Answer 18

1. Intiation- dental lamina
2. Morphogenesis- bud/cap
3. Cytodifferentiaton- bell
4. Matrix secretion
5. Root formation

Question 19

What forms the root? How may this affect the dentition in later life?

Answer 19

HERS- can persist as debris of Malssez (can be source of cyst formation)

Question 20

What are the different parts in the late bell stage?

Answer 20

Internal enamel epithelium

External enamel epithelium

Stellate reticulum

Stratum intermedium