File:Mesoderm-cartoon4.jpg

Mesoderm and Ectoderm Development cartoon

The cartoon above is a section through the trunk of the trilaminar embryo showing the further development of the 3 layers and the space (coelom) that forms in the mesoderm (only the righthand side is shown, lefthand side would be identical).

• ectoderm - neural plate has now formed the neural tube and neural crest separation from the overlying epithelial ectoderm.
• mesoderm - lateral plate mesoderm division into somatic and splanchnic mesoderm separated by intra-embryonic coelom.
• endoderm - forms epithelia and glads of gastrointestinal tract, associated organs and also the respiratory tract.

Within the embryonic disc lateral plate mesoderm a space (coelom) forms, it lies within the embryo and so is called the intraembryonic coelom.

This single "horseshoe-shaped" space will form the 3 major body cavities: pericardial (around the heart), pleural (around the lungs) and peritoneal (around the GIT and visceral organs).

The mesoderm adjacent to the endoderm is now called the splanchnic mesoderm which forms the connective tissue and muscular wall of the gastrointestinal tract.

Note intraembryonic coelomic cavity communicates with extra-embryonic coelom (space outside the embryo) through portals (holes) initially on lateral margin of embryonic disc.

Simplified Cartoon of Mesoderm and Ectoderm Development (week 3-4)

• Mesoderm and Ectoderm Cartoons
• 

  Trilaminar Embryo

• 

  Paraxial and Lateral Plate

• 

  Somites

• 

  Somatic and Splanchnic

Mesoderm Links: 1 Trilaminar Embryo | 2 Paraxial and Lateral Plate | 3 Somites | 4 Somatic and Splanchnic | Animation | Mesoderm | Somitogenesis | Notochord

Cite this page: Hill, M.A. (2024, April 24) Embryology Mesoderm-cartoon4.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Mesoderm-cartoon4.jpg

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