2010 BGD Practical 3 - Notochord: Difference between revisions

Latest revision as of 21:21, 9 May 2010

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).

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.

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.
The notochordal canal may appear to break down on the endodermal side forming a notochordal plate continuous with the endodermal layer.
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

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


Chorionic Cavity	Amniotic Cavity	Week 3

Glossary Links

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

Cite this page: Hill, M.A. (2024, April 18) Embryology 2010 BGD Practical 3 - Notochord. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2010_BGD_Practical_3_-_Notochord

What Links Here?

@@ Line 4: / Line 4: @@
 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).
+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).
-[[File:Stage7 axial process.jpg]]
+[[File:Stage7 axial process.jpg]] [[File:Mesoderm cartoon1.gif]][[File:Stage11 sem100c.jpg||thumb|stage 11 Embryo]]
@@ Line 15: / Line 15: @@
 # 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==
-{{Template:2010BGDLab3}}
-{| class="prettytable"
-| 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).
+[[File:Stage7 folding.jpg|left]] '''Folding:''' all edges of the embryonic disc will fold ventrally, forming a rostro-caudal "C" shaped tube.
-| [[Image:Stage7n3.jpg]][[Image:image_001.gif]]
-&nbsp;
-|}
-== Stage 7 ==
+{| border='0px'
-{| class="prettytable"
-| [[Image:Stage7n3.jpg]]
-| Carnegie Stages 7
-'''Features:''' embryonic disc, primitive node, primative streak, primitive groove, yolk sac
-'''Facts:''' Week 3, 15 - 17 days, 0.4 mm
-'''View 1:''' embryonic disc, showing the epiblast viewed from the amniotic (dorsal) side.
-'''Events:''' Gastrulation is continuing as cells migrate from the epiblast, continuing to form mesoderm.
-Mesoderm lies between the ectoderm and endoderm as a continuous sheet except at the buccopharyngeal and cloacal membranes. These membranes have ectoderm and endoderm only and will lie at the rostral (head) and caudal (tail) of the gastrointestinal tract.
 |-
-| [[Image:Stage7n2.jpg]]
+| [[File:Chorion 001 icon.jpg|120px|link=Development Animation - Chorionic Cavity]]
-| '''Axes:'''
+| [[File:Amnion 001 icon.jpg|120px|link=Development Animation - Amniotic Cavity]]
+| [[File:Week3_folding icon.jpg|120px|link=Development Animation - Week 3]]
-embryonic disc is shown rostral (head) to top and caudal (tail) to bottom.
-Left and right are the lateral margins of the disc as shown.
-&nbsp;
-|-
-| [[Image:Stage7n4.jpg]]
-| '''Folding:'''
-all edges of the embryonic disc will fold ventrally, forming a rostro-caudal "C" shaped tube.
 |-
-| [[Image:Stage7n5.jpg]]
+| [[Development Animation - Chorionic Cavity|Chorionic Cavity]]
-| '''Gastrulation:'''
+| [[Development Animation - Amniotic Cavity|Amniotic Cavity]]
+| [[Development_Animation_-_Week 3|Week 3]]
-Through the '''primitive streak '''cells migrate continuously through week 3 into week 4. Initial cells replace hypoblast as an epithelial layer the '''endoderm'''. Later migrating cells spread between the two epithelial layers to form '''mesoderm'''.
 |-
-| [[Image:Stage7n6.jpg]]
-| '''Axial Process:'''
-From the '''primitive node''' a tube extends under the ectoderm in the opposite direction to the primitive streak. This tube forms first the axial process, then notochordal process, and finally the notochord.
-The notochord is a key to embryonic folding and regulation of ectoderm and mesoderm differentiation. It lies in the rostrocordal axis and the embryonic disc will fold either side ventrally, pinching off a portion of the yolk sac to form the lining of the gastrointestinal tract.
-'''Next:''' [Stage8.htm Carnegie Stage 8 Unlabelled] | [Stage8L.htm Stage 8 Labelled]
 |}
-&nbsp;
-== Notochord Development ==
-Diagrams showing formation of the axial process which then forms the notochord (also called axial mesoderm). This mesodermal column of cells determines the direction of embryonic disc folding and signals the differentiation of nearby mesoderm (somites) and overlying ectoderm (neural plate then tube).
-[[Image:axial.jpg]]
-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.
-(a) 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.
-(b) The notochordal canal may appear to break down on the endodermal side forming a notochordal plate continuous with the endodermal layer.
-(c) 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).
-(figures- Moore and Persaud, 1998)
-{{Template:BGDFooter2010}}
-== Terms ==
-* '''bilaminar'''- having 2 layers
-* '''blastocyst-''' the developmental stage following morula, as this stage matures, the zona pellucia is lost allowing the conceptus to adplant and then implant into the uterine wall.
-* '''inner cell mass'''- the clump of cells found inside the blastocyst. These cells will go in to form the embryo, these are the "stem cells" (we here about in the media) that are totipotential, they can form any tissue in the embryo. Mature oocyte-the female germ cell released at ovulation from the ovary.
-* '''parental genomes'''- the male (sperm) and female (oocyte) DNA which contributes to the embryo's cells.
-* '''trilaminar embryonic disc'''- the 3 layered embryo stage.
-* '''Trophoblasts'''- (Gr. trophe = nutrition) outer layer of cells on blastocyst that will generate the embryonic part of the placenta.
+{{Template:2010BGDLab3}}
 {{Template:BGDFooter2010}}