Figure 4
From: In vitromaturation is slowed in prepubertal lamb oocytes: ultrastructural evidences
General morphology and organelle microtopography in prepubertal (a) and adult (b) ovine cumulus-oocyte-complexes (COCs) after 7 hours of IVM. a) Representative TEM micrograph showing the germinal vesicle (GV), the oolemma juxtaposed to the ZP and trans-zonal projections (arrows). Bar: 5 μm. Inset in a): representative LM image showing the round shape of the oocyte. Bar: 20 μm. b) Representative TEM micrograph showing spikes of the oolemma. The nucleus is not present. A layer of microvilli (mv) is visible in the perivitelline space (PVS). Va: vacuole; m: mitochondria; LD: lipid droplets. Bar: 2 μm. Inset in b): representative LM image showing spikes of the oolemma, uncontinuously adherent to the ZP. The apparent increased thickness of the zona pellucida, the wide PVS and scarce cytoplasm are effects of the section plane (not equatorial). Bar: 20 μm.