Changes

*Implantation is critical to the survival of the embryo; the embryo must adhere and embed itself in the endometrium in order to exchange waste and nutrients. For this reason, the first differentiation of cells is into trophoblasts and syncytiotrophoblasts and the inner cell mass (ICM).  

*Implantation is critical to the survival of the embryo; the embryo must adhere and embed itself in the endometrium in order to exchange waste and nutrients. For this reason, the first differentiation of cells is into trophoblasts and syncytiotrophoblasts and the inner cell mass (ICM).  

**Trophoblastic cells posses adhesion molecules to adhere to the endometrium whilst ICM cells form the organism.  

**Trophoblastic cells posses adhesion molecules to adhere to the endometrium whilst ICM cells form the organism.  

#Hypoblast - facing towards the endometrium, adjacent to the blastocyst cavity.

#Hypoblast - facing towards the endometrium, adjacent to the blastocyst cavity.

#Amnioblasts - cells of the epiblast that migrate up and around to allow the amniotic cavity to form.  

#Amnioblasts - cells of the epiblast that migrate up and around to allow the amniotic cavity to form.  

*After [[Developmental Biology - Gastrulation - Anatomy & Physiology|gastrulation]] the '''epiblast''' gives rise to the three germ layers:

*After [[Gastrulation - Anatomy & Physiology|gastrulation]] the '''epiblast''' gives rise to the three germ layers:

#Ectoderm

#Ectoderm

#Mesoderm

#Mesoderm