Question

briefly describe what happens 30-40 hours post fertilization

Answer 1

30 hours post fertilization, It is no larger than the head of a pin. Still rapidly dividing, the developing embryo, called a zygote at this stage, floats down from the fallopian tube and towards the uterus.

The 4-cell embryo is the result of a second cleavage event, and occurs at approximately 40 hours after fertilization. The individual cells are called blastomeres. The zygote undergoes a number of ordinary mitotic divisions that increase the number of cells in the zygote but not its overall size. Each cycle of division takes about 24 hours. At this stage, the process of embryonic genome activation is initiated in human embryos, and lasts until the 8-cell stage. The resulting morula stage marks the first morphological indication of a break in radial symmetry.