BGDA Practical 3 - Gastrulation: Difference between revisions
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| Gastrulation means "gut forming" and converts the inner cell mass which then formed the bilaminar embryo (epiblast, hypoblast) into the trilaminar embryo (ectoderm, mesoderm, endoderm). | | Gastrulation means "gut forming" and converts the inner cell mass which then formed the bilaminar embryo (epiblast, hypoblast) into the trilaminar embryo (ectoderm, mesoderm, endoderm). | ||
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(Image: Nishimura etal., 1977) | (Image: Nishimura etal., 1977<ref>{{Ref-Nishimura1977}}</ref>) | ||
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[[File:Chicken-gastrulation3.jpg]] | [[File:Chicken-gastrulation3.jpg]] | ||
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| [[File:Trilaminar_embryo.jpg]] | |||
| Scanning electron micrograph showing the early forming 3 layers: ectoderm, mesoderm and endoderm. The embryonic disc has been broken to expose these early layers that form the entire embryo. | |||
# [[Ectoderm]] - columnar epithelium | |||
# [[Mesoderm]] - embryonic connective tissue (mesenchyme) | |||
# [[Endoderm]] - cuboidal epithelium | |||
* The amniotic cavity would lie above the ectoderm layer. | |||
* The yolk sac would initially lie below the endoderm layer, later this would be the gastrointestinal tract within the embryo. | |||
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| <html5media height="500" width="390">File:Mesoderm_001.mp4</html5media> | |||
[[File: | [[Media:Mesoderm_001.mp4|'''Click Here''' to play on mobile device]] | ||
| valign="top" |[[File:Mesoderm_001_icon.jpg|100px|right]] | |||
Now observe this brief animation of mesoderm development during week 3. | Now observe this brief animation of mesoderm development during week 3. | ||
'''Mesoderm Development''' | |||
* This animation shows the migration of mesoderm throughout the embryonic disc during gastrulation. | |||
* The pink arrow show how mesodermal cells spread out between the ectoderm and endoderm layers, forming the third (middle) layer of the '''trilaminar''' embryo. | |||
* '''Axial process''' - the arrow running from the '''primitive node''' upward is the axial process which will later form the '''notochord'''. | |||
* 2 regions where no mesoderm is found, at the upper and lower ends of the gastrointestinal tract. | |||
# cranial (top) - '''buccopharyngeal membrane''' | |||
# caudal (bottom) - '''cloacal membrane'''. | |||
* '''Prechordal plate''' - lies above the '''buccopharyngeal membrane''' and is the cardiogenic mesoderm, that will form the heart. | |||
:'''Links:''' [[Media:Mesoderm_001.mp4|MP4 version]] | [[Gastrulation]] | [[Mesoderm]] | [[Week 3]] | |||
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===References=== | |||
<references/> | |||
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{{BGDA Practical 3 - Gastrulation Interactive}} | |||
{{ | {{BGDALab3}} | ||
[[Category:Gastrulation]] |
Latest revision as of 14:40, 6 May 2019
Practical 3: Oogenesis and Ovulation | Gametogenesis | Fertilization | Early Cell Division | Week 1 | Implantation | Week 2 | Extraembryonic Spaces | Gastrulation | Notochord | Week 3 |
Introduction
Gastrulation means "gut forming" and converts the inner cell mass which then formed the bilaminar embryo (epiblast, hypoblast) into the trilaminar embryo (ectoderm, mesoderm, endoderm).
The process involves the migration of cells from the epiblast layer through the primitive streak to form first the endoderm layer and then a second intermediate layer the mesoderm layer. Once all cells have left the epiblast layer it now becomes the ectoderm layer. These three germ cell layers (ectoderm, mesoderm, endoderm) will form in a layer specific manner all the future tissues of the developing embryo.
Approximate cross-section of an 18 day human conceptus. Identify the 3 layers of the trilaminar embryo: ectoderm (columnar cells), intraembryonic mesoderm (mesenchymal cells, endodermal cells (cuboidal single layer). Identify primitive groove with dense cluster of primitive streak cells below it.
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Stage 7
Gastrulation
Carnegie Stage 7 and 8, gastrulation, migration of cells through the primitive streak to form endoderm and mesodermal layers of embryo.
Scanning electron micrograph showing the early forming 3 layers: ectoderm, mesoderm and endoderm. The embryonic disc has been broken to expose these early layers that form the entire embryo.
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<html5media height="500" width="390">File:Mesoderm_001.mp4</html5media> |
Now observe this brief animation of mesoderm development during week 3. Mesoderm Development
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References
- ↑ Nishimura H. Semba R. Tanimura T. and Tanaka O. Prenatal development of the human with special reference to craniofacial structures : An atlas. (1977) U.S. Dept. of Health, Education, and Welfare, Public Health Service, National Institutes of Health ; Washington. Bethesda, Md.
Interactive Component
Attempt the Quiz - Gastrulation |
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Here are a few simple Quiz questions that relate to Gastrulation from the lecture and practical.
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Practical 3: Oogenesis and Ovulation | Gametogenesis | Fertilization | Early Cell Division | Week 1 | Implantation | Week 2 | Extraembryonic Spaces | Gastrulation | Notochord | Week 3 |