Three-dimensional reconstruction of the bovine sperm connecting piece. A) Three-dimensional volume rendition of the bovine connecting piece from electron cryotomography, showing segments used in cross-section views. B–C) Cross-sections of isosurface rendering of the reconstructed volume representing the densities at the sampling segments z2 and z3, respectively. Numbers of each ODF were assigned according to [7]; b, bar structure. D) Longitudinal section of a sperm CP corresponding to the sampling plane y in A. E–G) Cross-sections of the corresponding cut planes z1–z3 in A, respectively. Supplemental Movie S3 displays all the longitudinal sections through the whole density. Bar = 250 nm (D–G). LR, left region; CR, central region; and RR, right region.