Spermatozoon: Difference between revisions
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Sperm makes girls really hot and it makes them get preggers with sperm and aids and shit. I love you VampireIX! |
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[[Image:Fertilisation.jpg|thumb|right|250px|A sperm cell attempts to penetrate an [[ovum]] coat to [[Fertilisation|fertilize]] it.]] |
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- Love Doli |
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A '''sperm cell''', '''spermatozooa''' (''pl.'' '''spermatozoa''') (in [[Greek language|Greek]]: ''sperma'' = seed and ''zoon'' = alive), or '''spermatozoan''', is the [[ploidy|haploid]] [[cell (biology)|cell]] that is the male [[gamete]]. It is carried in fluid called [[semen]], and is capable of [[fertilisation|fertilising]] an [[ovum|egg cell]] to form a [[zygote]]. A zygote can grow into a new [[organism]], such as a human being. <br /> |
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Sperm cells contain half of the [[gene|genetic information]] available to the [[diploid]] offspring. In mammals, the [[sex]] of the offspring is determined by the sperm cells, through the [[Chromosome|chromosomal]] pair "XX" (for a [[female]]) or "XY" (for a [[male]]). Sperm cells were first observed by [[Anton van Leeuwenhoek|Antoni van Leeuwenhoek]] in [[1679]]. |
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==Spermatozoan structure and size== |
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Individual spermatozoa are highly differentiated cells, composed normally of a head, basal body (or ''midpiece''), and [[flagellum|tail]]. The head contains some [[cytoplasm]] and the [[cell nucleus|nuclear]] material for [[fertilization]]. It also contains some enzymes which give it the ability to break through the egg to commence fertilisation. The [[basal body]] contains a large concentration of [[mitochondria]] that provide the energy for sperm mobility through the production of [[adenosine triphosphate|ATP]]. The spermatozoan tail is typically a [[flagellum]] used for propulsion. |
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In humans, sperm cells consists of a head 5 [[micrometre|µm]] by 3 µm and a tail 50 µm long. The [[Reynolds number]] associated with spermatazoa is in the order of 1E-2, so it is known that the spermatazoa exhibits [[laminar flow]]. Spermatazoan stream lines are straight and parallel. The tail [[flagellate]]s, which we now know propels the sperm cell (at about 1-3 mm/minute in humans) by rotating like a propeller, not side to side like a whip. The cell is characterized by a minimum of cytoplasm. During fertilization, the sperm's [[mitochondria]] gets destroyed by the egg cell, and this means only the mother is able to provide the baby's mitochondria and [[mitochondrial DNA]], which has an important application in tracing maternal [[ancestry]]. However it has been recently discovered that mitochondrial DNA can be recombinant. |
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The largest spermatozoa belongs to the [[fruit fly]]. |
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== Sperm cell production == |
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''Main article:'' [[Spermatogenesis]] |
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Spermatozoa are produced in the [[seminiferous tubule]]s of the [[testes]] in a process called spermatogenesis. Round cells called [[spermatogonia]] divide and differentiate eventually to become spermatozoa. During [[copulation]] the [[cloaca]] or [[vagina]] gets [[insemination|inseminat]]ed, and then the spermatozoa move through [[chemotaxis]] to the ovum inside a [[Fallopian tube]] or the [[uterus]]. |
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== The acrosome reaction == |
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The female [[ovum]] is coated in a thick protective [[membrane]]. When a sperm cell reaches the egg the acrosome releases its enzymes. These enzymes break down the cell membrane, allowing the sperm cell passage into the egg where the sperm [[fusion|fuses]] with the egg cells membrane, and empties its genetic content into the egg. Upon penetration the membrane of the egg cell undergoes a change and becomes impenetratable, preventing further [[fertilization]] of the ovum. |
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== See also == |
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* [[sperm competition]] |
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* [[sperm heteromorphism]] |
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== External links == |
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* [http://www.andrologysociety.com/resources/handbook.asp The Handbook of Andrology] |
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[[Category:Male reproductive system]] |
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[[Category:Germ cells]] |
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[[Category:Andrology]] |
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[[af:Semen]] |
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[[bg:Сперматозоид]] |
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{{Link FA|de}} |
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[[es:Espermatozoide]] |
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[[fr:Spermatozoïde]] |
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[[he:זרע (אנטומיה)]] |
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[[io:Spermatozoido]] |
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[[it:Spermatozoo]] |
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[[ja:精子]] |
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[[lt:Spermatozoidas]] |
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[[nl:Zaadcel]] |
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[[no:Spermie]] |
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[[pl:Plemnik]] |
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[[ru:Сперматозоид]] |
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[[simple:Sperm]] |
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[[su:Spérma]] |
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[[sv:Spermie]] |
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[[zh:精子]] |
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Revision as of 23:48, 2 February 2006
Sperm makes girls really hot and it makes them get preggers with sperm and aids and shit. I love you VampireIX!
- Love Doli