Development of the ovarian follicle is characterized by dramatic changes in the granulosa compartment. The number of granulosa cells doubles 21 times from the primordial follicle to the 18-mm preovulatory follicle. There is also differentiation of the membrana granulosa cells, with marked differences occurring between cells at different stages of follicular development and relative to their position within the membrana granulosa. The follicular basal lamina surrounds the oocyte-(antrum)-granulosa complex throughout follicular development—excludingcapil-laries, white blood cells, and nerve processes from the granulosa compartment—nntil it isdegradedatovulation. Ithas been postulated that the follicular basal lamina regulates the fate of the granulosa cells, consistent with the role of basal laminae in influencing cell proliferation, differentiation, and migration and in maintaining polarity of other cell types. The follicular basal lamina might also play a role in filtering out the larger molecules of serum during the accumulation of follicular fluid. flovent inhaler
The functions of basal laminae throughout the body are very tightly related to their composition. Basal laminae are often composed of a lattice-type network of type IV collagen intertwined with a network of laminin. This structure is stabilized by the binding of entactin to the collagen and laminin and by low-affinity interactions between type IV collagen and laminin.