Amelogenesis Flashcards
what are the 4 stages of amelogenesis
pre-secretory
secretory
transition to maturation
post-maturation
what happens in the pre-secretory phase
the IEE cells differentiate to become tall columnar pre-ameloblasts
what does the pre-ameloblasts cell look like
nucleus away from the basal lamina
what happens in the secretory phase
pre-ameloblasts develop into ameloblasts with fully developed Tomes Processes on their secretory end.
deposition of the organic enamel proteins tuftelin/ amelogenin and inorganic components of enamel follow. Formation of HAP crystals and prism formation.
what is the role of the Tomes Processes on the ameloblast cells
packed with secretory vesicles which deposit the inorganic AND organic portions of enamel. formation of HAP prisms.
what happens to the ameloblast cell in the later stages of secretory phase
when all the enamel has been secreted, the cell becomes wider and the nucleus moves back down
what happens in the transition to maturation phase
the full thickness of enamel is achieved therefore enamel production STOPS.
50% cell death, cells lose tomes processes
what happens to the ameleoblast cell in the transition to maturation phase
cells shrink in size, lose tomes processes, and have a wider base
what happens in the post-maturation phase
the ameleoblasts shrink to form a protective layer for enamel
what is the difference in % of protein in mature and immature enamel
in mature 1% organic/protein
in immature, early forming enamel 30% (both non-ameleogenin and amelogenin proteins)
which cells diffrentiate to become pre-ameloblasts
the IEE cells of the growing enamel organ
what is meant by ‘polarised cell’
when the nucelus moves away from the basal lamina
in ameloblasts this means nucleus moves UP
in odonotobasts this means nucleus moves DOWN
what is meant by ‘polarised cell’
when the nucelus moves away from the basal lamina
in ameloblasts this means nucleus moves UP
in odonotobasts this means nucleus moves DOWN
