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A caplike structure at the anterior end of a spermatozoon that produces enzymes aiding in egg penetration.

ac′ro·so′mal (-sō′məl) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Physiology) a cap-like structure on the tip of a spermatozoon that releases enzymes on encountering the ovum allowing fusion with the ovum in the sexual reproductive process; this part of the process is known as the acrosome reaction
[C19: from acro- + -some3]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈæk rəˌsoʊm)

an organelle covering the head of animal sperm and containing enzymes that digest the egg cell coating, thus permitting the sperm to enter the egg.
[1895–1900; < German Akrosoma; see acro-, -some3]
ac`ro•so′mal, adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.acrosome - a process at the anterior end of a sperm cell that produces enzymes to facilitate penetration of the eggacrosome - a process at the anterior end of a sperm cell that produces enzymes to facilitate penetration of the egg
sperm, sperm cell, spermatozoan, spermatozoon - the male reproductive cell; the male gamete; "a sperm is mostly a nucleus surrounded by little other cellular material"
appendage, outgrowth, process - a natural prolongation or projection from a part of an organism either animal or plant; "a bony process"
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Once the high-calcium sea-water reached the sperm, the acrosome burst, followed by the rapid growth of a slender acrosomal process over the next several seconds.
Extraordinary divergence and positive Darwinian selection in a fusagenic protein coating the acrosomal process of abalone spermatozoa.
During the acrosome reaction, the extension of the acrosomal process occurs through rapid, localized polymerization of Gactin into filamentous actin (F-actin).
stouti show that acrosomal exocytosis of hagfish spermatozoa forms an acrosomal process, as is often seen in the spermatozoa of invertebrates, and that it produces numerous vesicles through membrane fusion at many points, which is also observed in the spermatozoa of many vertebrates (Morisawa, 1999a; Morisawa and Cherr, 2002).
First, after the acrosomal reaction, bindin self-associates, coating the acrosomal process. Second, it functions in sperm-egg attachment by binding to carbohydrates in the vitelline layer on the egg surface.
Firstly, there is no extrusion of an acrosomal process or "perforatorium" by the polymerization of actin, as occurs throughout molluscs and other metazoan groups (see review by Tilney, 1985).