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Human Notochord Development Theories

Textbook concepts compared to proposed theory. Schematic summary of the two main developmental concepts in modern textbooks.

Ventral view with removed endoderm. The black lines indicate the level of the transversal sections (epiblast/ectoderm is superior in each section).

A - textbook B - proposed theory
Notochord develops in two phases.


First the notochordal process (NP) extends over almost the entire length of the embryo (left). Within the notochordal process is a luminal extension of the primitive pit. The NP intercalates between the endoderm and the bottom of the NP ‘breaks down’ along the length of the neurenteric canal. This process results in the notochordal plate (right), which retracts between the mesenchyme forming the definitive notochord.

All precursors of the notochord are simultaneously present.


We now know that the NP is shorter in length and that the definitive notochord does not develop cranially in the embryo, but merely in the middle region.


(See paper Figs 3 and 5)

Definitive notochord (DN): red, endoderm: light grey (in sections), epiblast or ectoderm: dark blue, dark grey (in sections), gastrulation area (GA): purple, neurenteric canal: white, notochordal plate (NPL): yellow, notochordal process (NPR): cyan blue, prechordal plate (PP): brown.

Reference

de Bree K, de Bakker BS & Oostra RJ. (2018). The development of the human notochord. PLoS ONE , 13, e0205752. PMID: 30346967 DOI.

Copyright

© 2018 de Bree et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Fig 1 doi: https://doi.org/10.1371/journal.pone.0205752.g001


Cite this page: Hill, M.A. (2024, April 17) Embryology Human notochord development theories 1.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_notochord_development_theories_1.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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