(1) Involution occurs here, as cells divide and push other cells into the blastocoel from the top of the dorsal lip.(2) Inside this spherical mass of cells, a fluid-filled cavity - the blastocoel - develops in the animal region and the embryo is now called a blastula.(3) The blastocoel appears bright grey, the animal cap darker-gray and the vegetal pole black.(4) These pouches eventually fill the blastocoel forming two new pouches, the coelom.(5) The graduate student of the well-known professor had furthered the experiment with mice blastocoels .(6) The blastocoelic cavity usually collapses during the early stages of implantation.(7) At blastula stage 8, cells forming the blastocoelic roof were cultured in isolation as explants.(8) An early blastocyst, containing a small amount of blastocoelic fluid, is shown to the right.
