Craniofacial Development and disorder Flashcards
In Epithelial Mesenchymal Interaction what does Induction, Cell Differentiation mean and what are unspecialised cells known as?
Epithelial Mesenchymal Interaction:
Induction: is the process in which an undifferentiated cell is instructed by specific organisers to produce a morphogenic effect.
Cell Differentiation: The organiser is the part of an embryo that influences another part to direct histologic and morphologic differentiation. Chemical substances such as growth factors and morphogens induce cells to initiate specific cellular Processes including DNA synthesis in a specific temporal and spatial manner.
These unspecialised cells are known as stem cells
What are the Prenatal Development stages?
- Perimplantaion period - first week
- Embryonic Period - second to eigth week
- Fetal period - third to ninth month
What is the process of the embryonic period?
In the embryonic process what does this allow the blastocyst to become, and what structures develops at this stage?
These processes cause the structure of the implanted blastocyst to become, with further development, an embryo.
These physiologic processes also allow the teeth and associated orofacial structures, as well as other organ structures, to develop in the embryo.
In the embryonic period what does these terms mean:
- Cytodifferentiation
- Histodifferentiation
- Morphodifferentiation
Cytodifferentiation is the development of different cell types.
Histodifferentiation is the development of different histologic tissue types within a structure.
Morphodifferentiation is the development of the differing morphology, which makes up its structure or shape, for each organ or system.
During the embryonic period, the complexity of the structure and function of these cells increases. How is this accomplished?
During the embryonic period, the complexity of the structure and function of these cells increases.
This is accomplished by morphogenesis, which is the process of development of specific tissue structure or shape.
During the second week of prenatal development, within the embryonic period, the implanted blastocyst grows by increased proliferation of the embryonic cells, with differentiation also occurring resulting in changes in cellular morphogenesis; every ridge, bump, and recess now indicates these increased levels of cellular differentiation.
What does this increased number of embryonic cells create?
During the second week of prenatal development, within the embryonic period, the implanted blastocyst grows by increased proliferation of the embryonic cells, with differentiation also occurring resulting in changes in cellular morphogenesis; every ridge, bump, and recess now indicates these increased levels of cellular differentiation.
This increased number of embryonic cells creates the embryonic cell layers (or germ layers) within the blastocyst.
What are the development of embryonic layers?
During the second week a bilaminar embryonic disc is eventually developed. What is this developed from and how does it appear?
• A bilaminar embryonic disc is eventually developed from the blastocyst and appears as a threedimensional but flattened, essentially circular plate of bilayered cells.
In the 3rd week what happens to the Bilaminar disk?
What is the epiblast layer now considered as?
With three layers present, the bilaminar disc has thickened into a trilaminar embryonic disc.
With the creation of the new embryonic cell layers of mesoderm and embryonic endoderm, the epiblast layer is now considered ectoderm.
During the fourth week of prenatal development within the embryonic period, what does the disc undergo?
During the fourth week of prenatal development within the embryonic period, the disc undergoes embryonic folding, establishing for the first time the axis
What are dynamic, reciprocal and sequential interactions?
Sequentially, timing of events
Reciprocal, one in control then other
Dynamic, happen quickly
Tissue interactions appear to be associated with at least 2 general types of phenomena, what are they?
- Instructive: the ability of one tissue to determine specific patterns of morphogenesis and differentiation that will develop in an associated tissue.
- Permissive (or facilitative): the ability of an interacting tissue to provide certain conditions that is necessary for its committed partner tissue to progress to full expression of its predetermined phenotype
What are the stages in development?
