Embryological Development

Embryological Development

1. Fertilization

   • Pronuclei fusion

2. Blastomere division

3. Morula

4. Blastocyst

   • embryoblast
     • Embryoblast: 2 layers
       • Epiblast
         • Gastrulation
           • ectoderm
             • CNS, PNS, skin, eyes, internal ear, neural crest cells
           • mesoderm
             • paraxial mesoderm
               • somites
             • intermediate mesoderm
               • urogenital
             • lateral plate mesoderm
               • splanchnic
                 • surrounds organs
               • somatic
                 • lines body cavities
           • endoderm
             • gut & gut derivatives
       • Hypoblast
   • trophoblast
     • Trophoblast: 2 layers
       • Cytotrophoblast
         • villi for placenta
       • Syncytiotrophoblast
   • fluid filled cavity

5. 3 cavities

   • amniotic
   • yolk sac
   • chorionic

6. Extraembryonic mesoderm: 2 layers

   • somatic
   • splanchnic