Mammal, canine ovary (LM, High)

Structure List Secondary follicle Beginning antrum Granulosa cells Basement membrane Theca interna Theca externa Zona pellucida Cytoplasm of ova

MATURE FOLLICLE (Graafian follicle) has the structures seen in the secondary follicle except each layer of cells enlarges and the collection of liquid in the antrum increases until the follicle projects from the surface of the ovary. The mature follicle varies in size from 5 to 10 mm in diameter in the dog or sheep, to 25-70 mm in the mare. When the follicle ruptures, the ovum and the attached corona radiata and the follicular liquid are discharged to be carried into the oviduct. Following rupture, the remaining cells of the follicle collapse into the follicular cavity to form the corpus luteum.