Low power TEM of a stage 3 embryo in vitro resulting from intracytoplasmic sperm injection of the ovum that was cultured for five days (original magnification x800).
The blastocystic cavity (blastocoele) (BC), inner cell mass (ICM), trophoblast (T), and zona pellucida (ZP) are well preserved. Some inner cell mass (embryoblast) cells are apoptotic.
From: Makabe et al., 2001. Reproduced with permission of the publisher, the Italian Journal of Anatomy & Embryology.
Keywords: apoptotic cells, inner cell mass (embryoblast), trophoblast, zona pellucida
Source: The Virtual Human Embryo.