Are the 4 cell types of enamel organ (IEE, OEE, SR and SI) first present in Bell stage and if so does that mean that in Cap stage they are all just classed as enamel organ as they are still differentiating?
A question from embryology section of practice exam: List two developmental abnormalities that can occur at this time. I looked it up in the lecture notes and in the Bath-Balogh textbook but there was no information on abnormalities during this particular stage. Would I be correct to say that they are the same as in Cap stage (eg Dens in dente, Gemination, Fusion)?
I was thinking that by this time (bell stage) it's too late for the differentiating cells to turn back etc, so whatever happened in the cap stage will just carry on to the bell stage, but the abnormalities listed may not necessarily have occured in the bell stage. Did that make sense? So I'm Kinda agreeing with what you're saying Mirela, if what I've written makes sense to anyone :-/
Im having the same trouble with answering the 'description of the component' of the enamel organ in the cap stage: at the moment I've just written, -a depression forms in the deepest part of each tooth bud to form a cap, also known as an enamel organ - In future enamel organ will form enamel for outter tooth surface
But then there is a slide that shows the 4 different types of cells OEE, IEE, SR, SI and its titled 'tooth development cap stage'
but then it says enamel organ assumes bell stage which results in differentiation of and four different types of cells are now found within the enamel organ?
So do we include this in our cap stage, or is it strictly just in the bell stage?
Hi all in terms of whether the enamel organ differentiates in the cap or the bell stage - remember it is a continuum, rather than separate stages. However it is generally considered that the enamel organ has differentiated into the 4 different types of cell (IEE, OEE, SI and SR) by the Bell stage - ie, when the enamel organ has the definite look of a bell. There would be the beginnings of differentiation in the cap stage, but in most texts I have read, they talk about the bell stage as being when differentiation mainly occurs. In terms of the abnormalities - I love Kimberly's description of 'it's too late to turn back' - which is on the right track. But more significant would be that if differentiation of the Enamel organ did not occur, amelogenesis and dentinogenesis imperfecta would occur in apposition as the cells necessary to induct the ameloblasts and odontoblasts would have have formed. Hope this all makes sense Cathy
I think I'm still a little confused in reference to the last point, so the abnormalities caused in the cap stage does carry on to the bell stage? OR is the abnormalities in the bell stage based on the lack of differentiation of the IEE into amelobasts and the outer cells of the dental papillae into odontoblasts, thus resulting in amelogenesis imperfecta or dentinigenesis imperfecta which will carry onto apposition? Sorry! Just having trouble understanding :-/
How I understand it is that it could be both. If abnormalities happen in cap stage it will just continue on to the next stage. However if the enamel organ does not differentiate into the 4 cell types and dental papilla into outer and central cells during bell stage that will result in amelogenesis and dentinogenesis imperfecta as there is no required cells present to start induction processes.
A question from embryology section of practice exam:
ReplyDeleteList two developmental abnormalities that can occur at this time.
I looked it up in the lecture notes and in the Bath-Balogh textbook but there was no information on abnormalities during this particular stage. Would I be correct to say that they are the same as in Cap stage (eg Dens in dente, Gemination, Fusion)?
I was thinking that by this time (bell stage) it's too late for the differentiating cells to turn back etc, so whatever happened in the cap stage will just carry on to the bell stage, but the abnormalities listed may not necessarily have occured in the bell stage.
ReplyDeleteDid that make sense? So I'm Kinda agreeing with what you're saying Mirela, if what I've written makes sense to anyone :-/
Me and Denny had the exact same query yesterday Mirella.. and I think what Kimberly says makes sense
ReplyDeleteIm having the same trouble with answering the 'description of the component' of the enamel organ in the cap stage:
ReplyDeleteat the moment I've just written,
-a depression forms in the deepest part of each tooth bud to form a cap, also known as an enamel organ
- In future enamel organ will form enamel for outter tooth surface
But then there is a slide that shows the 4 different types of cells OEE, IEE, SR, SI and its titled 'tooth development cap stage'
but then it says enamel organ assumes bell stage which results in differentiation of and four different types of cells are now found within the enamel organ?
So do we include this in our cap stage, or is it strictly just in the bell stage?
Hi all
ReplyDeletein terms of whether the enamel organ differentiates in the cap or the bell stage - remember it is a continuum, rather than separate stages.
However it is generally considered that the enamel organ has differentiated into the 4 different types of cell (IEE, OEE, SI and SR) by the Bell stage - ie, when the enamel organ has the definite look of a bell.
There would be the beginnings of differentiation in the cap stage, but in most texts I have read, they talk about the bell stage as being when differentiation mainly occurs.
In terms of the abnormalities - I love Kimberly's description of 'it's too late to turn back' - which is on the right track. But more significant would be that if differentiation of the Enamel organ did not occur, amelogenesis and dentinogenesis imperfecta would occur in apposition as the cells necessary to induct the ameloblasts and odontoblasts would have have formed.
Hope this all makes sense
Cathy
I think I'm still a little confused in reference to the last point, so the abnormalities caused in the cap stage does carry on to the bell stage? OR is the abnormalities in the bell stage based on the lack of differentiation of the IEE into amelobasts and the outer cells of the dental papillae into odontoblasts, thus resulting in amelogenesis imperfecta or dentinigenesis imperfecta which will carry onto apposition? Sorry! Just having trouble understanding :-/
ReplyDeleteHow I understand it is that it could be both. If abnormalities happen in cap stage it will just continue on to the next stage. However if the enamel organ does not differentiate into the 4 cell types and dental papilla into outer and central cells during bell stage that will result in amelogenesis and dentinogenesis imperfecta as there is no required cells present to start induction processes.
ReplyDeleteAh, that makes much more sense, thanks Mirela! ;)
ReplyDelete