File:Stage5 bf22b.jpg

Human Embryo Carnegie Stage 5

Carnegie Collection Embryo No.7700 (stage 5c)

Facts: About 12 days, embryonic disc, 0.204 x 0.165 mm, chorionic cavity, 0.55 x 0.498 mm and chorion, 0.948 x 0.835 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).

Stage 5 Links: Embryo No.8004 - Surface view | Embryo No.8004 - near implantation site | Embryo No.8004 - Stage 5b | Embryo No.8004 - Stage 5b labeled | Embryo No.8004 - Rotated view | Embryo No.7700 - implantation site | Embryo No.7700 - Stage 5c | 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

Cite this page: Hill, M.A. (2024, April 16) Embryology Stage5 bf22b.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Stage5_bf22b.jpg

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G