Superficial epithelial cells slough off into lumen. Largely small, round, nucleated epithelial cells, singly or in sheets. None to few leucoytes. Estrus Ovulation in the rat is spontaneous and occurs about 10 hours after the beginning of estrus. Usually 10-20 eggs ovulated each time.
Epithelial cells reach maximum development.
Outer layer of epithelial cells become cornified and sloughed into the lumen. In early estrus these cells retain their nuclei, but in later stages no nuclei visible and the cells are irregular, flat, cornified plates. The skin around the vaginal orifice becomes swollen. Metestrus Many corpora lutea, which secrete only for a very short time, and small follicles. Epithelium continues vacuolar degeneration and replacement.