Scanning electron micrograph of a hamster oocyte cumulus complex. Cumulus cells (purple) and matrix (gray) are shown. Small blood clots (red) also often appear in oocyte cumulus complexes. The red blo...

Hamster oocyte and cumulus cells. This scanning electron micrograph shows a hamster oocyte. The oocyte is not directly visible but lies beneath the zona pellucida. The surface of the zona pellucida c...

Colorized scanning electron micrograph of a human egg. The egg is surrounded by a glycoprotein coat called the zona pellucida which aids in trapping and binding the sperm. Two residual coronal cells f...

Light micrograph of human ovum (egg) and sperm. The ovum is much larger than the sperm and is surrounded by protective cumulus cells around the outside surface (yellow). The membrane surrounding the o...