UNSW Embryology

Carnegie Stage 13

© Dr Mark Hill (2008)

Acknowledgements

Carnegie Stage 13 (day 28) Facts: Week 5, 28 - 32 days, 4 - 6 mm, Somite Number 30 View: Lateral view. Amniotic membrane removed. Features: site of midbrain, lens placode, site of nasal placode, 1,2,3 pharyngeal arches, L. ventricular prominence of heart, L. atrial prominence of heart, umbilical cord, lower limb bud, mesonephric prominence, upper limb bud Identify: site of midbrain, lens placode, site of nasal placode, 1st, 2nd and 3rd pharyngeal arches, L. ventricular prominence of heart, L. atrial prominence of heart, umbilical cord, lower limb bud, mesonephric prominence, upper limb bud Labelled Stage 13

Events

Ectoderm: sensory placodes, lens placode, otocyst (=otic vesicle), early site of nasal placode, forebrain

Mesoderm: continued segmentation of paraxial mesoderm (30 somite pairs), heart prominence

Head: 1st, 2nd and 3rd pharyngeal arch, forebrain, site of lens placode, site of otic placode, stomodeum

Body: heart, liver, umbilical, upper limb bud, lower limb bulge

Organogenesis

Cross-section through the stage 13 embryo at the level of the forelimb bud showing the internal development of organs and nervous system.

Note the relative underdevelopment of the musculoskeletal system at this stage.

Next - Carnegie Stages 14

Stage 14 Unlabelled | Stage 14 Labelled

Glossary of Terms

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Carnegie Stage images

The Kyoto Collection images are reproduced with the permission of Prof. Kohei Shiota for tutorial/revision purposes and cannot be reproduced electronically or in writing without permission.

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