Lecture 2: Odontogenesis Flashcards Preview

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Flashcards in Lecture 2: Odontogenesis Deck (19)
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1
Q

teeth arise from what germ layer?

A

ectoderm

2
Q

odontogenesis begins in what week?

A

6th

3
Q

what, in chronological order, are the 4 epithelial stages of teeth formation?

A
  • epithelial dental lamina stage (6th week)
  • epithelial bud stage
  • epithelial cap stage
  • epithelial bell stage (enamel organ)(four layers)
4
Q

what are the three parts of the tooth germ

A
  • enamel bell/organ (epithelium)
  • dental papilla (mesenchyme)
  • dental follicle (mesenchyme)
5
Q

cells arising from the dental laminae (primary and secondary) become the odontogenic ___ part of the a tooth germ

A

epithelial

6
Q

the epithelial bud cells are continuous with the cells of what?

A

primary dental lamina

7
Q

concerning primary buds, what is the timeline for central incisors and second molars?

A

central incisors= 6 weeks in utero

second molars= 8 weeks in utero

8
Q

concerning permanent buds, what is the timeline for first molars, central incisors, second molars, and third molars

A

first molar= 4 months in utero
central incisor= 5 months in utero
second molar= 10 months postnatally
third molar= 5 years postnatally

9
Q

concerning the cap stage, what is the concentration of epithelial cells that is a signaling center which determines if the tooth will develop to become an anterior or posterior tooth

A

enamel knot

10
Q

from inner to outer, what are the four layers of the enamel organ/bell stage?

A
  • inner epithelium
  • stratum intermedium epithelial layer
  • stellate reticulum epithelial layer
  • outer epithelial layer
11
Q

secondary dental lamina is facial/lingual to the primary

A

lingual

12
Q

secondary dental lamina arises from where?

A

primary dental lamina (not oral epithelium)

13
Q

what is the only part of the tooth germ that is avascular?

A

enamel organ

14
Q

after the formation of enamel is complete, the ameloblasts, along with the other layers of the enamel organ come together over the surface of the enamel as a protective structure called what?

A

reduced enamel epithelium

15
Q

the undifferentiated cells (stem cells) of the dental papilla become what three things? and what does the dental papilla ultimately become?

A
  • -odontoblasts
  • -fibroblasts
  • -reserve cells

-pulp tissue

16
Q

the undifferentiated cells (stem cells) of the dental follicle become what 4 things? and what does the dental follicle ultimately become?

A
  • -cementoblasts
  • -fibroblasts
  • -osteoblasts
  • -reserve cells

-periodontal ligament

17
Q

the enamel organ is attached to both mesenchymal parts of the tooth germ by a ___ ___

A

basal lamina

18
Q

when does the reduced enamel epithelium stop protecting the enamel?

A

when the tooth enters the oral cavity

19
Q

the outer and inner layers of the enamel organ come together, at the cervical loop, forming a double epithelial layer called what? and what 2 main functions does it have?

A

hertwig’s epithelial root sheath

  • -determines root dentin outline
  • -determines # of root canals of teeth