The ovary is a complex endocrine organ with both a cortex and a medulla. The medulla contains primarily loose connective tissue, blood vessels, and nerves, but few follicles. The ovarian cortex is composed of primordial and developing follicles, corpora lutea, and corpora albicantia distributed in loose connective tissue known as the interfollicular stroma (Fig. 1). © 2005 Humana Press Inc.