Fig. 2
From: Stereological study of organelle distribution in human mature oocytes
Ultrastructural images of metaphase-II oocytes. (A) First polar body (PB1), showing chromosomes (chr), chromosomal microtubules (mt), mitochondria (mi), smooth endoplasmic reticulum (SER) small vesicles (SV) and cortical vesicles (cv). The PB1 is inserted in the perivitelline space (pvs), between the zona pellucida (ZP) and the oolemma. The oocyte surface contained microvilli (mv), outside the PB1 apposition region. In the ooplasm it can be observed cortical vesicles (cv), mitochondria (mi), smooth endoplasmic reticulum (SER) small (SV), medium (MV) and large (LV) vesicles, SER isolated tubules (IT), and SER small tubular aggregates (*). (A, B) Oocyte chromosomes (chr) at the metaphase-II plate. (A, C, D) Cortical vesicles (cv) were observed to form layers under the oolemma, with some presenting decondensed contents. (D) Tiny coated-vesicles (arrows) were observed at the oocyte surface. Bars: (A, B, C) 1 μm; (D) 0.5 μm.
