Fig. 56. TEM of the polar trophoblast region of a stage 3 embryo in vitro, 145-170 hours post-insemination (original magnification x12,000). Extensive cytoplasmic processes of polar trophoblast cells extend toward the zona pellucida between the sequestered cells.
CP, cytoplasmic processes of polar trophoblastic cells; SC, sequestered cells; ZP, zona pellucida.
(From: Lopata, Kohlman, and Kellow, 1982. Reproduced with permission of the publisher, John Wiley & Sons.)
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