File:Stage 9 SEM1.jpg

From Embryology

Stage_9_SEM1.jpg(347 × 450 pixels, file size: 42 KB, MIME type: image/jpeg)

Human Embryo (Carnegie Stages 9)

Features: embryonic disc, primitive node, primative streak, primative groove, somites, neural groove, brain plate region, connecting stalk, cut edge of amnion

Facts: Week 3, 19 - 21 days, 1.5 - 2.5 mm, Somite Number 1 - 3

View 1: embryonic disc, showing the epiblast viewed from the amniotic (dorsal) side.

Events: Ectoderm - Neural plate brain region continues to expand, neural plate begins folding over the notochord. Mesoderm - segmentation of paraxial mesoderm begins (1 - 3 somite pairs), cardiac primordium forms

Identify: neural groove and neural folds, the mesoderm, which segments beside the neural groove to form somites but extends laterally to margin of embryonic disc lateral plate mesoderm, where it merges with the covering extraembryonic mesoderm.

The intra-embryonic coelom develops in the middle of the lateral plate mesoderm. Note amniotic ectoderm covered by extramebryonic mesoderm (empty spaces above and below the mesoderm are artefacts, as are the lateral folds in the ectoderm).

Original file name: 3-4SomiteSt9d20dorsal.jpg

Image Source: Scanning electron micrographs of the Carnegie stages of the early human embryos are reproduced with the permission of Prof Kathy Sulik, from embryos collected by Dr. Vekemans and Tania Attié-Bitach. Images are for educational purposes only and cannot be reproduced electronically or in writing without permission.

Embryonic Development

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, March 2) Embryology Stage 9 SEM1.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Stage_9_SEM1.jpg

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

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current11:51, 9 August 2009Thumbnail for version as of 11:51, 9 August 2009347 × 450 (42 KB)S8600021 (talk | contribs)Carnegie Stages 9 Features: embryonic disc, primitive node, primative streak, primative groove, somites, neural groove, brain plate region, connecting stalk, cut edge of amnion Facts: Week 3, 19 - 21 days, 1.5 - 2.5 mm, Somite Number 1 - 3 View 1: emb