Talk:1987 Developmental Stages In Human Embryos - Stage 1

Table 1-1. Tabulaton of the First Three Stages

Stage	Event		Products
	Meiotic division 1			Oocyte 2 and polar body 1
	Beginning of meiotic division 1 and ovulation			Ovulated oocyte
1a	Fertilization	Penetration	Penetrated oocyte
1b			Completion of meiotioc division 2 and formation of pronuclei	Ootid and polar body 2
1c			Pronuclei enter cleavage division	Zygote
2	Cleavage continues			2 to about 16 cells
3	Formation of blastocystic cavity			Blastocyst, from about 32 cells onward