2010 BGD Practical 3 - Gastrulation: Difference between revisions
No edit summary |
|||
| Line 28: | Line 28: | ||
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. | ||
[[Image:Stage7n2.jpg]] | |||
'''Axes:''' | |||
embryonic disc is shown rostral (head) to top and caudal (tail) to bottom. | embryonic disc is shown rostral (head) to top and caudal (tail) to bottom. | ||
| Line 36: | Line 35: | ||
Left and right are the lateral margins of the disc as shown. | Left and right are the lateral margins of the disc as shown. | ||
[[Image:Stage7n4.jpg]] | |||
'''Folding:''' | |||
all edges of the embryonic disc will fold ventrally, forming a rostro-caudal "C" shaped tube. | all edges of the embryonic disc will fold ventrally, forming a rostro-caudal "C" shaped tube. | ||
[[Image:Stage7n5.jpg]] | |||
'''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'''. | 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'''. | ||
==Movies== | ==Movies== | ||
Revision as of 20:34, 9 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
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.
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 through the streak region showing the early forming 3 layers: ectoderm, mesoderm and endoderm.
Stage 7
Features: embryonic disc, primitive node, primative streak, primitive groove, yolk sac
Facts: Week 3, 15 - 17 days, 0.4 mm
View 1: embryonic disc, showing the epiblast viewed from the amniotic (dorsal) side.
Events: Gastrulation is continuing as cells migrate from the epiblast, continuing to form mesoderm.
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.
File:Stage7n2.jpg 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.
Folding:
all edges of the embryonic disc will fold ventrally, forming a rostro-caudal "C" shaped tube.
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.
Movies
|
|
|
|
|
| Implantation | Mesoderm | Chorionic Cavity | Amniotic Cavity | Week 3 |
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 19) 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
