Source:http://linkedlifedata.com/resource/umls/id/C0600485
GO: The discharge, by sperm, of a single, anterior secretory granule following the sperm's attachment to the zona pellucida surrounding the oocyte. The process begins with the fusion of the outer acrosomal membrane with the sperm plasma membrane and ends with the exocytosis of the acrosomal contents into the egg. [GOC:dph, PMID:3886029],MSH: Changes that occur to liberate the enzymes of the ACROSOME of a sperm (SPERMATOZOA). Acrosome reaction allows the sperm to penetrate the ZONA PELLUCIDA and enter the OVUM during FERTILIZATION.