File talk:Stage2 bf01.jpg
From Embryology
Carnegie No. 8698
- 2 cells described by Hertig etal. (1954).
- Tubal Diameter, 178.5 um (122 x 88 after fixation; 111.6 X 75 after sectioning)
- blastomeres, 71 (74 x 64 and 80 x 56 after fixation; 68.3 x 61.6 and 70 x 50 after sectioning)
- polar bodies, 20 x 18 after fixation.
- A few cells of the corona radiata were present.
- Thick zona pellucida (18um in thickness before fixation).
- No spermatozoa were seen in the zona, and the possibility of parthenogenetic cleavage "cannot be entirely ruled out" (Dickmann etal, 1965).
- Two polar bodies.
- Whether the larger blastomere "is the one of trophoblastic potential is unknown but it is probable" (Hertig, 1968).
- Believed to be about I-2 days old.
