title: Human sperm head ultrastructure: a freeze-etching study.
mesh_terms: D000818:Animals; D001718:Birefringence; D002417:Cattle; D002462:Cell Membrane; D002467:Cell Nucleus; D002875:Chromosomes; D004247:DNA / Q000032:analysis; D005613:Freeze Etching; D005615:Freezing; D006652:Histological Techniques; D006654:Histology, Comparative; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D011817:Rabbits; D013094:Spermatozoa / Q000032:analysis / Q000166:cytology*
chemical_list: D004247:DNA