4 Amelogenesis Flashcards
What process occurs at marked red spots during presecretory stage of amelogenesis?
Site of initial cellular differentiation: inner epeithelial cells –> ameloblast
Red spot marks cells that indicate what phase of the presecretory stage of amelogenesis?
Ameloblasts: histodifferentiation phase
Red spot marks tissue that indicates what occurs first: enamel or dentin secretion?
Dentin tissue (before enamel)
Which red spot marked cell is the first to differentiate?
Top: ameloblast differentiates first (before odontoblast)
Bottom: the odontoblast differentiates after the ameloblast
Maturated or unmaturated mineralized tissue?
Enamel: partially mineralized/unmatured.
Note: if enamel were fully mineralized, an “enamel space” would be present due to tissue processing.
Which marks site of alkaline phosphatase needed for enamel mineralization?
Left: Yes, stratum intermedium epithelial cell layer
Right: No, dental follicle of tooth germ
Which site is avascular?
Top: Yes, this enamel organ part of the tooth germ is avascular.
Bottom: No, this dental papilla part of tooth germ is highly vascular.
Are cells marked by the red spot in the presecretory, secretory, or postsecretory stage of amelogeneis?
Inner epithelial cells of enamel organ in presecretory stage (destined to be come ameloblast)
Do the red spots indicate presecretory, secretory, or postsecretory stage?
L: secretory stage of amelogeneis, enamel tissue is partially mineralized.
R: secretory stage of amelogenesis, ameloblast.
The moropholgy of the cells at red spot indicate they are in which phases of amelogensis?
Ameloblasts with Tomes’ processes indicate interrod substances and enamel rod phases.
Red marked structure appears during the interrod substance phase of the secretory stage of amelogensis. What is this structure called?
Tomes’ process: it secretes interrod substance and a rod of enamel.
Red spot marked site appears during the interrod substance phase of the secretory stage of amelogenesis. What is it called?
Tomes’ pit (location of Tomes’ process)
Which red spot marks blood supply needed for enamel mineralization?
Top: Yes, the dental follicle of the tooth germ.
Bottom: No, the dental papilla of the tooth germ.
Red spot marks a site that disappears during the histodifferentiation phase of amelogenesis. What is it called?
Red spot is acellular or clear layer of tooth germ.
Red spot marks a structure that remains intact throughout the presecretory phase. What is it called?
Basal lamina = attaches epithelial part of tooth germ to mesencymal part.
The red spots mark two areas of the enamel organ that become important structures during amelogenesis. Identify.
- REE = reduced enamel epithelium.
- Hertwig’s epithelial root sheath (HERS)
Red spot marks a structure that appears during a phase of the postsecretory stage of amelogenesis. Identify.
REE: Reduced enamel epithelium; remnant of cells of the enamel organ
Red spot marks a structure that arises from the cervical loop area of an enamel organ during the postsecretory stage of amelogensis. What is it called?
Hertwig’s epithelial root sheath = merger of outer and inner cell layers of the enamel organ.
Which appears during a phase of the postsecretory stage and serves a protective function?
Top: Yes, REE
Bottom: No, HERS
Which are differentiated?
All are differentiated!
Left is odontoblasts.
Right is ameloblasts.
Ameloblasts, enamel, Tomes’ Prcoess
Enamel
Ameloblasts
Tomes’ process
Where do ameloblasts differentiate?
Inner layer
Immature enamel
Ameloblasts
Stratum intermedium
Stratum intermedium
Ameloblasts
Immature enamel
Marks partially mineralized enamel?
Top: YES, this immature enamel becomes fully mineralized during the maturation phase of amelogenesis.
Bottom: NO, this is mineralized dentin.
Dentin
Outer rodless enamel
Inner rodless enamel
Outer rodless enamel
Inner rodless enamel
Dentin
