Human Growth and Development

Prenatal Development-Embryonic Period

What four events follow fertilization?

The four events that occur immediately following fertilization are cleavage, implantation, placentation, and embryogenesis. Immediately after fertilization, the single cell divides into two cells. During cleavage, these cells continue to divide. Each division brings two new cells called blastomeres. Each blastomere is approximately half the size of the parent cell. Cleavage occurs as the cells move from the uterine tube to the uterine cavity.

