Secondary follicle with large antrum.

The antrum of this secondary follicle is quite large. Some of the proteins in the follicular liquor stained light pink. The oocyte, which has reached its maximum size, is surrounded by the corona radiata* and sits on the cumulus oophorous. (*Strictly, the corona radiata refees to the rim of cells that enclose the oocyte that leaves the follicle at ovulation. In other words, a free floating object. Here the term is used a bit more loosely since we are not likely to catch the oocyte in the act of escaping. Compare the size of this follicle with the smaller ones in the cortex, using the surface epithelium as a reference and you can appreciate how large this secondary follicle is. PK1464. Original mag. 25x H&E. Secondary follicle. Cortex. Ovary. Female Reproductive System. Cat.