Gastrulation: Difference between revisions
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:'''Links:''' [[Lecture_-_Week_3_Development|Lecture - Week 3]] | [[Week 3]] | [[Carnegie stage 7|stage 7]] | [[Carnegie stage 8|stage 8]] | [[Endoderm]] | [[Mesoderm]] [[Ectoderm]] | [[Developmental_Mechanism_-_Epithelial_Mesenchymal_Transition|Epithelial Mesenchymal Transition]] | [[Notochord]] | :'''Links:''' [[Lecture_-_Week_3_Development|Lecture - Week 3]] | [[Week 3]] | [[Carnegie stage 7|stage 7]] | [[Carnegie stage 8|stage 8]] | [[Endoderm]] | [[Mesoderm]] | [[Ectoderm]] | [[Developmental_Mechanism_-_Epithelial_Mesenchymal_Transition|Epithelial Mesenchymal Transition]] | [[Notochord]] | ||
::[[Embryology_History|Historic Embryology]]: [[Book_-_Manual_of_Human_Embryology_5|Gastrulation (1910)]] | [[Book - The Frog Its Reproduction and Development_7|Frog Gastrulation (1951)]] | ::[[Embryology_History|Historic Embryology]]: [[Book_-_Manual_of_Human_Embryology_5|Gastrulation (1910)]] | [[Book - The Frog Its Reproduction and Development_7|Frog Gastrulation (1951)]] |
Revision as of 08:28, 30 April 2013
Introduction
Gastrulation means the formation of gut (Greek, gastrula = belly), but has now a more broad sense to to describe the formation of the trilaminar embryo. The epiblast layer, consisting of totipotential cells, derives all 3 embryo layers: endoderm, mesoderm and ectoderm. The primitive streak is the visible feature which represents the site of cell migration to form the additional layers.
Historically, gastrulation was one of the earliest observable morphological event occurring in the frog embryo. Currently, the molecular and physical mechanisms that regulate patterning and migration during this key event are being investigated in several different animal models. In humans, it is proposed that similar mechanisms regulate gastrulation to those found in other vertebrates.
- primitive node - region in the middle of the early embryonic disc epiblast from which the primitive streak extends caudally (tail)
- nodal cilia establish the embryo left/right axis
- axial process extends from the nodal epiblast
- primitive streak - region of cell migration from the epiblast layer forming sequentially the two germ cell layers (endoderm and mesoderm)
Epithelial to Mesenchymal Transition
Epithelial cells (organised cellular layer) which loose their organisation and migrate/proliferate as a mesenchymal cells (disorganised cellular layers) are said to have undergone an Epithelial Mesenchymal Transition (EMT). Mesenchymal cells have an embryonic connective tissue-like cellular arrangement, that have undergone this process may at a later time and under specific signaling conditions undergo the opposite process, mesenchyme to epithelia. In development, this process can be repeated several times during tissue differentiation.
This process occurs at the primitive streak where epiblast cells undergo an epithelial to mesenchymal transition in order to delaminate and migrate.
- Links: Lecture - Week 3 | Week 3 | stage 7 | stage 8 | Endoderm | Mesoderm | Ectoderm | Epithelial Mesenchymal Transition | Notochord
Some Recent Findings
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Human Gastrulation
The site of gastrulation, the primitive streak is visible during week 3 on the epiblast dorsal surface of the embryonic disc.
Stage 7
- Links: Carnegie stage 7
Stage 8
Primitive pit |
Primitive groove and primitive streak |
Gastrulation Concepts
- Links: Chicken Development
Gastrulation Movies
Animation showing the secondary spread of mesoderm following the migration of endoderm through the primitive streak.
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Germ Layer Markers
Stem cell researchers have used the following markers to identify early differentiation of cells in the three germ layer in embryoid bodies.[3]
- Ectoderm - SOX1
- Mesoderm - Brachyury T
- Endoderm - Alpha-Fetoprotein
- Links: Induced Stem Cells | Alpha-Fetoprotein
Additional Images
References
Reviews
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Articles
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Books
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External Links
External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.
- UNSW Embryology Movie - Gastrulation | Epithelial Mesenchymal Transition
- Gastrulation: From Cells to Embryo Supplemental Data and Figures
Glossary Links
- Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link
Cite this page: Hill, M.A. (2024, June 14) Embryology Gastrulation. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Gastrulation
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G