High power TEM of the cytoplasm of a stage 1b embryo in vitro, 24 hours post-insemination (original magnification x19,500). A crystalline inclusion (CI) is composed of a bundle of rods with pointed ends. Also shown is a grazing section through a curve of the principle piece (PP) of the fertilizing sperm flagellum. The ribs of the sperm course longitudinally and transversely. A portion of the axial filament complex is cut longitudinally.
From: Soupart and Strong, 1974. Reproduced with permission of the American Society for Reproductive Medicine.
Keywords: axial filament complex (AFC), crystalline inclusion, cytoplasm, principle piece (PP), ribs of the sperm, sperm flagellum, stage 1b embryo
Source: The Virtual Human Embryo.