Microstructure of Spermatozoa after Denudation as Revealed by the Electron Microscope

Abstract

The microstructure of spermatozoa was investigated using electron microscopy and denudation of the sperm cell by chemical reagents. Electron micrographs show that the acrosome appears to be composed of a tubular sheath and a central core; it is covered by the galea capitis. The structure covering the axial filament (a.f.) of the spermatozoon has been removed by denuding the sperm with NaOH. The micrographs demonstrate that there are 9 fibrils in the a.f. of the sperm from human, cattle, sheep, swine and rabbit. The fibrils appear as thin ribbons of at least 2 distinct thicknesses. Cross striations of fibrils have been observed and each of the 9 fibrils appears at consist of even finer sub-units. The microstructure of the broad helix (b.h.) has been revealed by the removal of the surrounding structure through pancreatic digestion. The micrographs show that the b.h. is composed of numerous granules lying together within the mitochondrial sheath. Also, micrographs show the continuation of the fibrils of the a.f. and the helical structure from the neck up to the extreme tail end of the sperm cell.