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.  

The extent of cellular growth and division and the time taken for [[Fertilisation, Implantation and Early Embryonic Development -Implantation- Anatomy & Physiology|implantation]] differs between species.

The extent of cellular growth and division and the time taken for [[Implantation - Anatomy & Physiology|implantation]] differs between species.

*Shortly after implantation cells of the ICM differentiate into different layers:

*Shortly after implantation cells of the ICM differentiate into different layers:

#Epiblast - facing towards the uterine lumen, adjacent to syncytiotrophoblasts.

#Epiblast - facing towards the uterine lumen, adjacent to syncytiotrophoblasts.