False-color SEM of an egg at ovulation

False-color SEM of an egg at ovulation
The egg (pink at centre) has ruptured the external surface of the ovary (brown), known as the germinal epithelium, and has started its journey through the Fallopian tube towards the uterus. The image clearly shows the thick glycoprotein layer (pink), the zona pellucida, which entirely surrounds the egg. The egg is also partly surrounded by cells (granulosa cells) and fluid (liquor folliculi), seen here in white and turquoise, which formerly provided nutrients and protection to the egg in the ovary.

Photo credit: professors P.M. Motta & J. Van Blerkom
Photo via SCIENCE PHOTO LIBRARY