Carnegie stage 3

Human blastocyst (day 5) still within zone pellucida.

Human Blastocyst "hatching" from zona pellucida, in early Embryonic Development designated as Carnegie stage 3. Blastocyst is too the right of image and Zona pellucida is shown to the left of the image. Note:

small opening in the zona pellucida through which the blastocyst is hatching
flattened trophoblast cells forming the outer cell layer of the blastocyst
inner cell mass shown in the centre of the image and on the left-hand wall of the blastocyst
blastocoel forming a large fluid-filled space within the blastocyst

Facts: Week 1, 4 - 5 days, size 0.1-0.2 mm

Features: zona pellucida, trophoblast shell, inner cell mass, blastoceol

Human Embryo, blastocyst (day 5)

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 23) Embryology Carnegie stage 3. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Carnegie_stage_3

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