2010 BGD Practical 3 - Gastrulation: Difference between revisions
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==Introduction== | ==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). | |||
===Practical Audio=== | |||
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BGD Cycle A 2010 Audio - Dr Mark Hill Monday 12th May 2010 12-2pm G2G4. | |||
:Note - this is a live unedited recording from the practical and may contain errors in either descriptions or content. | |||
[[Media:BGD2010-Embryo Lab 120510-308.mp3|listen Part 8]] | [[:File:BGD2010-Embryo Lab 120510-308.mp3|download]] (1 Mb MP3 8:21) | |||
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| [[File:Human_embryo_day_18.jpg|300px]] | |||
| 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. | 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. | 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. | |||
(Image: Nishimura etal., 1977) | |||
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== Stage 7 == | == Stage 7 == | ||
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'''Features:''' embryonic disc, primitive node, primative streak, primitive groove, yolk sac | |- | ||
| [[File:Stage7-sem2.jpg|300px]] | |||
| [[File:Stage7_features.jpg]] | |||
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| '''Features:''' embryonic disc, primitive node, primative streak, primitive groove, yolk sac | |||
'''Facts:''' Week 3, 15 - 17 days, 0.4 mm | '''Facts:''' Week 3, 15 - 17 days, 0.4 mm | ||
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Mesoderm lies between the ectoderm and endoderm as a continuous sheet except at the buccopharyngeal and cloacal membranes. These membranes have ectoderm and endoderm only and will lie at the rostral (head) and caudal (tail) of the gastrointestinal tract. | Mesoderm lies between the ectoderm and endoderm as a continuous sheet except at the buccopharyngeal and cloacal membranes. These membranes have ectoderm and endoderm only and will lie at the rostral (head) and caudal (tail) of the gastrointestinal tract. | ||
embryonic disc is shown rostral (head) to top and caudal (tail) to bottom. | | '''Gastrulation:''' Through the '''primitive streak '''cells migrate continuously through week 3 into week 4. Initial cells replace hypoblast as an epithelial layer the '''endoderm'''. Later migrating cells spread between the two epithelial layers to form '''mesoderm'''. | ||
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| [[File:Stage7_primitive_streak_labelled.jpg]] | |||
| [[File:Stage7 axes.jpg]] | |||
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| '''Axes:''' embryonic disc is shown rostral (head) to top and caudal (tail) to bottom. Left and right are the lateral margins of the disc as shown. | |||
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== Gastrulation == | |||
Carnegie Stage 7 and 8, gastrulation, migration of cells through the primitive streak to form endoderm and mesodermal layers of embryo. | |||
[[File:Chicken-gastrulation3.jpg]] | |||
[[File:Trilaminar_embryo.jpg]] | |||
Scanning electron micrograph showing the early forming 3 layers: ectoderm, mesoderm and endoderm. | |||
[[File:Mesoderm 001 icon.jpg|200px|link=Development_Animation_-_Mesoderm]] | |||
{{Template:2010BGDLab3}} | {{Template:2010BGDLab3}} |
Latest revision as of 20:42, 12 May 2010
Practical 3: Oogenesis and Ovulation | Gametogenesis | Fertilization | Early Cell Division | Week 1 | Implantation | Week 2 | Extraembryonic Spaces | Gastrulation | Notochord | Week 3 | Quiz
Introduction
Practical Audio
BGD Cycle A 2010 Audio - Dr Mark Hill Monday 12th May 2010 12-2pm G2G4.
listen Part 8 | download (1 Mb MP3 8:21) |
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.
Practical 3: Oogenesis and Ovulation | Gametogenesis | Fertilization | Early Cell Division | Week 1 | Implantation | Week 2 | Extraembryonic Spaces | Gastrulation | Notochord | Week 3 | Quiz
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
- 2010 BGD: Lecture 1 | Lecture 2 | Practical 3 | Practical 6 | Practical 12
Cite this page: Hill, M.A. (2024, April 26) Embryology 2010 BGD Practical 3 - Gastrulation. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2010_BGD_Practical_3_-_Gastrulation
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G