acrosome


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acrosome

 [ak´ro-sōm]
the caplike, membrane-bound structure covering the anterior portion of the head of a spermatozoon; it contains enzymes involved in penetration of the ovum.
Acrosome of a spermatozoon. From Applegate, 2000.
acrosome reaction changes in the spermatozoon that result in development of perforations in the acrosome, allowing release of enzymes that facilitate fertilization.

ac·ro·some

(ak'rō-sōm),
A caplike organelle or saccule derived from Golgi elements that surround the anterior two thirds of the nucleus of a sperm. Enzymes contained within this structure probably facilitate the sperm's penetration of the zona pellucida of the oocyte.
Synonym(s): acrosomal cap, head cap
[acro- + G. soma, body]

acrosome

/ac·ro·some/ (ak´ro-sōm) the caplike, membrane-bound structure covering the anterior portion of the head of a spermatozoon; it contains enzymes for penetrating the oocyte.

acrosome

(ăk′rə-sōm′)
n.
A caplike structure at the anterior end of a spermatozoon that produces enzymes aiding in egg penetration.

ac′ro·so′mal (-sō′məl) adj.

acrosome

[ak′rəsōm′]
Etymology: Gk, akron + soma, body
the caplike structure surrounding the anterior end of the head of a spermatozoon. It is derived from the Golgi apparatus within the cytoplasm and contains degradative enzymes that function in the penetration of the ovum during fertilization. Also called acrosomal cap, acrosomal head cap. See also acrosomal reaction. acrosomal, adj.

Acrosome

A membrane-bound cap-like structure at the head of a spermatozoon that contains lytic enzymes—e.g., acrosin hyaluronidase—which degrade the ovum’s zona pellucida, allowing the penetration of one sperm.

acrosome

Reproduction biology A membrane-bound cap-like structure at the head of a spermatozoon that contains lytic enzymes–acrosin hyaluronidase which degrade the outer coat of the egg and allow the penetration of one sperm. See Acrosome reaction. Cf Capacitation.

ac·ro·some

(ak'rō-sōm)
A caplike organelle that surrounds the anterior two thirds of the nucleus of a sperm. Within this cap are enzymes that are thought to facilitate entry of the sperm into the oocyte.
[acro- + G. soma, body]

acrosome

A tiny sac or double membrane in the head of a SPERMATOZOON that contains the digestive enzymes needed to break down the protective cell membrane of the egg (OVUM) and allow penetration. Release of these enzymes is called the acrosome reaction.
Acrosomeclick for a larger image
Fig. 8 Acrosome . Head of a typical mammalian sperm.

acrosome

a membrane-bound sac derived from the GOLGI APPARATUS, located at the tip of the sperm. The acrosome plays an important role in fertilization. It contains enzymes that, when the sac ruptures upon contact with the egg, aid in penetration of the egg membrane, so allowing transfer of the sperm nucleus to the egg cell. See Fig. 8 .

acrosome

the caplike, membrane-bounded structure that covers the anterior portion of the head of the mammalian spermatozoon; it is bounded by an inner and an outer membrane and contains enzymes involved in penetration of the ovum.

acrosome reaction
fusion of the outer acrosomal membrane with the sperm plasma membrane, and the breakdown of the fused complex, after the attachment of the spermatozoon to the zona pellucida. It is induced by substances from the egg investments and releases enzymes involved in penetration of the ovum.
References in periodicals archive ?
Figures 1-3 present the results of different concentrations of used amino acids on post-thaw motility, progressive motility, viability, membranes and acrosome integrity of ram spermatozoa.
The average volume (ml), sperm concentration (107/ml), mass activity (1-5), motility (%), progressive motility (%), viability (%) and rate of morphologically normal acrosome (%) in the ejaculates of Markhoz goat spermatozoa were 1.
The effect of heparin, caffeine and calcium ionophore A23187 on in vitro induction of the acrosome reaction in frozen-thawed bovine and caprine spermatozoa.
Overall, the results showed a significant deterioration in the acrosome integrity up to 48 h, thereafter there was not much degradation of integrity.
However, it has been reported that glucose is an essential component for inducing the acrosome reaction of spermatozoa and for supporting fertilization in mice (Fraser and Quinn, 1981).
High molecular mass egg fucose sulfate polymer is required for opening both Ca2+ channels involved in triggering the sea urchin sperm acrosome reaction.
Sperm capacitation is enhanced by the uterine environment and hormones, which completes the acrosome reaction (Phelps et al.
Characterization of porcine oviductal epithelial cells, cumulus cells and granulosa cells-conditioned media and their ability to induce acrosome reaction on frozen-thawed bovine spermatozoa.
Stages Diameter Time Unfertilized eggs 180 [micro]m 0 sec Sperm attached to egg 185 [micro]m 20-30 sec Sperm acrosome reaction 185 [micro]m ~1 min Sperm-egg membrane fusion 180 [micro]m 2-3 min Appearance of first polar body 185 [micro]m 8-9 min Appearance of second 185 [micro]m 10 min polar body First cleavage 200 [micro]m 15-20 min Second cleavage 195 [micro]m 35-40 min Morula 200 [micro]m 45-55 min Blastula 192 [micro]m 75-85 min Gastrula 192 [micro]m 85-90 min Trochophore larvae 210 [micro]m 90-250 min Early veliger 225 [micro]m 5-24 h Late veliger 228 [micro]m 28-40 h Early creeping larvae 230 [micro]m 48-72 h Creeping larvae 300 [micro]m 3-6 days Juvenile 2 [micro]m 30 days
HP was the most potent GAG for enhancing sperm motility and inducing the acrosome reaction.
No significant differences were observed in acrosome damage, following the supplementation of the freezing extender with anti-oxidants, following the freeze-thawing process.