2010 BGD Practical 3 - Notochord

From Embryology
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Practical 3: Oogenesis and Ovulation | Gametogenesis | Fertilization | Early Cell Division | Week 1 | Implantation | Week 2 | Extraembryonic Spaces | Gastrulation | Notochord | Week 3 | Quiz


Introduction

The embryonic structure which establishes body axes and patterns surrounding tissues is called the notochord.

The notochord is a midline column of cells running in a rostrocaudal direction (head-tail) within the mesoderm layer. It exists as a transient developmental patterning structure with a role in molecular signaling (patterning) and controlling the direction of embryonic disc folding (mechanical). These images are of the embryonic disc in week 3 (stage 7).

Stage7 axial process.jpg Mesoderm cartoon1.gif

stage 11 Embryo


The notochordal process begins as a fold of ectoderm extending cranially toward the prechordal plate region. The sequence of differentiation: notochordal process -> notochordal plate -> notochord.

  1. Elongation of the notochordal process cranially from the primitive pit as a hollow tube (notochordal canal) in the midline of the embryonic disc underlying the ectoderm.
  2. The notochordal canal may appear to break down on the endodermal side forming a notochordal plate continuous with the endodermal layer.
  3. Notochordal plate folds to form notochord. The notochord (also called axial mesoderm) is an embryonic structure that regulates differentiation of surrounding structures including the overlying ectoderm (neural plate) and mesoderm (somites).

Disc Folding

Stage7 folding.jpg

Folding: all edges of the embryonic disc will fold ventrally, forming a rostro-caudal "C" shaped tube.


Chorion 001 icon.jpg Amnion 001 icon.jpg Week3 folding icon.jpg
Chorionic Cavity Amniotic Cavity Week 3


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Practical 3: Oogenesis and Ovulation | Gametogenesis | Fertilization | Early Cell Division | Week 1 | Implantation | Week 2 | Extraembryonic Spaces | Gastrulation | Notochord | Week 3 | Quiz


Glossary Links

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2010 BGD: Lecture 1 | Lecture 2 | Practical 3 | Practical 6 | Practical 12

Cite this page: Hill, M.A. (2019, December 12) Embryology 2010 BGD Practical 3 - Notochord. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2010_BGD_Practical_3_-_Notochord

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© Dr Mark Hill 2019, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G