|
Facts: Week 1 - 2, size 0.1 - 0.2 mm
Features: implantation completed, inner cell mass, bilaminar embryo, trophoblast development
- The conceptus completes implantation during this stage.
- The trophoblast cells (syncytiotrophoblast and cytotrophoblast) proliferate. Syncytiotrophoblast cells continue to invade the maternal endometrium and cytotrophoblast cells form clumps that will later form sites of chorionic villi formation.
- The maternal endometrium locally begins the decidual process and the endometrial stroma accumulates fluid (edematous).
- The extraembryonic cavities begin to form.
- The bilaminar embroyonic disc forms from the inner cell mass (embryoblast).
- Links: Lecture - Week 1 and 2 Development | Implantation | Week 2
- Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline
File:Chorion 001 icon.jpg</wikiflv>
|
Animation (left) shows the events following implantation and focuses on changes in the the spaces surrounding the embryonic disc, the extraembryonic coelom.
The blastoceol cavity is converted into two separate spaces: the yolk sac and the chorionic cavity.
The third space lies above the epiblast, the amniotic cavity.
- blue - epiblast layer
- yellow - hypoblast layer
- red cells - extraembryonic mesoderm layer
- green - trophoblast layer
- red spaces - blood-filled spaces, maternal lacunae
- white cells - (left) endometrial gland (right) endometrial epithelium
|
Quicktime movie
|
|
Stage 5a
Stage 5b
Stage 5c
- Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline
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, April 26) Embryology Carnegie stage 5. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Carnegie_stage_5
- What Links Here?
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
|