Collagens in the human ovary and ovulatory follicle. (a) Collagen type I (brown) in the human ovarian capsular stroma, showing a distribution of collagen type I in concentric layers (long arrows) with bundles (short arrows) joining the concentric layers. (b) Collagen type I (brown) in the theca externa (TE) and (c) collagen type III (brown) in the theca interna (TI) of a human preovulatory follicle. Nova Red stain. BL, basal lamina; GC, granulosa cells. [Reproduced with permission from Lind A-K, Weijdegard B, Dahm-Kahler P. Collagens in the human ovary and their changes in the perifollicular stroma during ovulation. Acta Obstet Gynecol Scand 2006;85(12):1476–1484.]