11 



Basic Features or Vertebrate Morpno^enesis 



A. Introduction 



1. Purpose of this chapter 



2. Definitions 



a. Morphogenesis and related terms 



b. Primitive, larval, and definitive body forms 



1 ) Primitive body form 



2) Larval body form 



3) Definitive body form 



3. Basic or fundamental tissues 



B. Transformation of the primitive body tubes into the fundamental or basic condition 

 of the various organ systems present in the primitive embryonic body 



1. Processes involved in basic system formation 



2. Fundamental similarity of early organ systems 



C. Laws of von Baer 



D. Contributions of the mesoderm to primitive body formation and later development 



1. Types of mesodermal cells 



2. Origin of the mesoderm of the head region 



a. Head mesoderm derived from the anterior region of the trunk 



b. Head mesoderm derived from the pre-chordal plate 



c. Head mesoderm contributed by neural crest material 



d. Head mesoderm originating from post-otic somites 



3. Origin of the mesoderm of the tail 



4. Contributions of the trunk mesoderm to the developing body 



a. Early differentiation of the somites or epimere 



b. Early differentiation of the mesomere (nephrotome) 



c. Early differentiation and derivatives of the hypomere 



1) Contributions of the hypomere (lateral plate mesoderm) to the developing 

 pharyngeal area of the gut tube 



2) Contributions of the hypomere (lateral plate mesoderm) to the formation 

 of the gut tube and heart structures 



3) Contributions of the hypomere (lateral plate mesoderm) to the external 

 (ectodermal or epidermal) body tube 



4) Contributions of the hypomere or lateral plate mesoderm to the dorsal body 

 areas 



5) Contributions of the lateral plate mesoderm to the walls of the coelomic 

 cavity 



5. Embryonic mesenchyme and its derivatives 



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