Ovaries on Day 6 of the Estrous Cycle.

Ovaries on Day 6 of the Estrous Cycle.
The left ovary shows a late corpus luteum that is now becoming sensitive to the action of prostaglandin F2alpha. Legend: 1 = follicle, 2 = corpus luteum, 4 = corpus albicans, 5 = ovarian stroma.

Pieterse MC (1999)