Changes

<br />

<br />

Cells within the '''morula''' continue to divide and a '''blastocyst''' (see above) develops, consisting of an '''inner cell mass''' or (ICM), a '''blastocoele''' cavity and a single layer of '''trophoblast''' cells. As fluid accumulates, the outer cells become flattened and a cavity known as the blastocoele is formed. At this stage, two separate cellular components emerge - the '''inner cell mass''' and the '''trophoblast'''.

Cells within the '''morula''' continue to divide and a '''blastocyst''' (see above) develops, consisting of an '''inner cell mass''' or (ICM), a '''blastocoele''' cavity and a single layer of '''trophoblast''' cells. As fluid accumulates, the outer cells become flattened and a cavity known as the blastocoele is formed. At this stage, two separate cellular components emerge - the '''inner cell mass''' and the '''trophoblast'''.

 

 

* Blastocyst continues mitosis.

Mitosis continues to occur within the '''blastocyst''' and fluid accumulates to fill the blastocoele and pressure within the embryo increases. Concurrent with growth and fluid accumulation is the production of '''proteolytic enzymes''' by '''trophoblastic''' cells.

* Fluid accumulates to fill the blastocoele and pressure within the embryo increases.

* Concurrent with growth and fluid accumulation is the production of '''proteolytic enzymes''' by '''trophoblastic''' cells.

* Enzymes weaken the '''zona pellucida'''.

* Enzymes weaken the '''zona pellucida'''.

* Blastocyst begins to contract and relax causing intermittent pressure pulses on the zona pellucida.

* Blastocyst begins to contract and relax causing intermittent pressure pulses on the zona pellucida.