Figure 6.

Outer mural granulosa cells send projections in many directions. (A) SEM image showing a region of inner and outer mural granulosa cells, the basal lamina, and theca cells and blood vessels found outside of the follicle. Four outer mural granulosa cells were chosen for reconstruction (three colored; one cell was not in the plane of the section). Scale bar, 5 μm. Video 8 shows 267 serial sections of this area. High-magnification insert shows parts of the cell bodies from outer mural granulosa cells on the bottom half and cell processes from theca or endothelial cells on the upper half. The basal lamina (BL) separates these cell types. Scale bar, 500 nm. (B) Reconstruction of 4 outer mural granulosa cell bodies and every cytoplasmic projection derived from them. Reconstruction is 16.4 × 14.7 × 22.4 μm (x, y, z), encompassing 497 serial sections (each, 45 nm-thick). A rotating view of this reconstruction can be seen in video 9. (C,D) Front and side views of reconstructed outer mural cells from (B), which were located 1–2 cell diameters away from the basal lamina (C) or directly adjacent to it (D).