Egg cell - Wikipedia

The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms The term is used when the female gamete is not ... Eggcell FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch "Ova"redirectshere.Forotheruses,seeOva(disambiguation). Femalereproductivecellinmostanisogamousorganisms NottobeconfusedwithEgg. EggcellAhumaneggcellwithsurroundingcoronaradiataDetailsIdentifiersLatinOvumGreekΩάριο(oário)MeSHD010063FMA67343Anatomicalterminology[editonWikidata] Humaneggcell Theeggcell,orovum(pluralova),isthefemalereproductivecell,orgamete,inmostanisogamousorganisms(organismsthatreproducesexuallywithalarger,femalegameteandasmaller,maleone).Thetermisusedwhenthefemalegameteisnotcapableofmovement(non-motile).Ifthemalegamete(sperm)iscapableofmovement,thetypeofsexualreproductionisalsoclassifiedasoogamous.Anonmotilefemalegameteformedintheoogoniumofsomealgae,fungi,oomycetes,orbryophytesisanoosphere.[1]Whenfertilizedtheoospherebecomestheoospore.[clarificationneeded] Wheneggandspermfuseduringfertilisation,adiploidcell(thezygote)isformed,whichrapidlygrowsintoaneworganism. Contents 1History 2Animals 2.1Mammalsincludinghumans 2.2Ooplasm 2.3Ovadevelopmentinoviparousanimals. 2.4Ovoviviparity 3Plants 4Otherorganisms 5Seealso 6References 7Externallinks History[edit] Whilethenon-mammaliananimaleggwasobvious,thedoctrineexovoomnevivum("everyliving[animalcomesfrom]anegg"),associatedwithWilliamHarvey(1578–1657),wasarejectionofspontaneousgenerationandpreformationismaswellasaboldassumptionthatmammalsalsoreproducedviaeggs.KarlErnstvonBaerdiscoveredthemammalianovumin1827.[2][3]Thefusionofspermatozoawithova(ofastarfish)wasobservedbyOskarHertwigin1876.[4][5] Animals[edit] Inanimals,eggcellsarealsoknownasova(singularovum,fromtheLatinwordovummeaning'egg').Thetermovuleinanimalsisusedfortheyoungovumofananimal.Invertebrates,ovaareproducedbyfemalegonads(sexglands)calledovaries.Anumberofovaarepresentatbirthinmammalsandmatureviaoogenesis.In2012,Whiteetal.disprovedthelongstandingdogmathatalloftheovaareproducedbeforebirth.TheteamfromtheVincentCenterforReproductiveBiology,Massachusetts,Bostonshowedthatoocyteformationtakesplaceinovariesofreproductive-agewomen.[6][7][clarificationneeded]Thisreportchallengedafundamentalbelief,heldsincethe1950s,thatfemalemammalsarebornwithafinitesupplyofeggsthatisdepletedthroughoutlifeandexhaustedatmenopause.[8] Mammalsincludinghumans[edit] Diagramofahumaneggcell Ovumandspermfusingtogether Theprocessoffertilizinganovum(Toptobottom) Inallmammalsexceptmonotremes,theovumisfertilizedinsidethefemalebody. Thehumanovagrowfromprimitivegermcellsthatareembeddedinthesubstanceoftheovaries.Eachofthemdividesrepeatedlytogivesecretionsoftheuterineglands,ultimatelyformingablastocyst.[9] Theovumisoneofthelargestcellsinthehumanbody,typicallyvisibletothenakedeyewithouttheaidofamicroscopeorothermagnificationdevice.[10]Thehumanovummeasuresapproximately120 μm(0.0047 in)indiameter.[11] Ooplasm[edit] Ooplasm(also:oöplasm)istheyolkoftheovum,acellsubstanceatitscenter,whichcontainsitsnucleus,namedthegerminalvesicle,andthenucleolus,calledthegerminaldisc.[12] Theooplasmconsistsofthecytoplasmoftheordinaryanimalcellwithitsspongioplasmandhyaloplasm,oftencalledtheformativeyolk;andthenutritiveyolkordeutoplasm,madeofroundedgranulesoffattyandalbuminoidsubstancesimbeddedinthecytoplasm.[12] Mammalianovacontainonlyatinyamountofthenutritiveyolk,fornourishingtheembryointheearlystagesofitsdevelopmentonly.Incontrast,birdeggscontainenoughtosupplythechickwithnutrimentthroughoutthewholeperiodofincubation.[12] Ovadevelopmentinoviparousanimals.[edit] Intheoviparousanimals(allbirds,mostfish,amphibiansandreptiles)theovadevelopprotectivelayersandpassthroughtheoviducttotheoutsideofthebody.Theyarefertilizedbymalespermeitherinsidethefemalebody(asinbirds),oroutside(asinmanyfish).Afterfertilization,anembryodevelops,nourishedbynutrientscontainedintheegg.Itthenhatchesfromtheegg,outsidethemother'sbody.Seeeggforadiscussionofeggsofoviparousanimals. Theeggcell'scytoplasmandmitochondriaarethesolemeanstheeggcanreproducebymitosisandeventuallyformablastocystafterfertilization. Ovoviviparity[edit] Thereisanintermediateform,theovoviviparousanimals:theembryodevelopswithinandisnourishedbyaneggasintheoviparouscase,butthenithatchesinsidethemother'sbodyshortlybeforebirth,orjustaftertheeggleavesthemother'sbody.Somefish,reptilesandmanyinvertebratesusethistechnique. Plants[edit] Nearlyalllandplantshavealternatingdiploidandhaploidgenerations.Gametesareproducedbythegametophyte,whichisthehaploidgeneration.Thefemalegametophyteproducesstructurescalledarchegonia,andtheeggcellsformwithinthemviamitosis.Thetypicalbryophytearchegoniumconsistsofalongneckwithawiderbasecontainingtheeggcell.Uponmaturation,theneckopenstoallowspermcellstoswimintothearchegoniumandfertilizetheegg.Theresultingzygotethengivesrisetoanembryo,whichwillgrowintoanewdiploidindividual(sporophyte).Inseedplants,astructurecalledtheovulecontainsthefemalegametophyte.Thegametophyteproducesaneggcell.Afterfertilization,theovuledevelopsintoaseedcontainingtheembryo.[13] Infloweringplants,thefemalegametophyte(sometimesreferredtoastheembryosac)hasbeenreducedtojusteightcellsinsidetheovule.Thegametophytecellclosesttothemicropyleopeningoftheovuledevelopsintotheeggcell.Uponpollination,apollentubedeliversspermintothegametophyteandonespermnucleusfuseswiththeeggnucleus.Theresultingzygotedevelopsintoanembryoinsidetheovule.Theovule,inturn,developsintoaseedandinmanycases,theplantovarydevelopsintoafruittofacilitatethedispersaloftheseeds.Upongermination,theembryogrowsintoaseedling.[13] GeneexpressionpatterndeterminedbyhistochemicalGUSassaysinPhyscomitrellapatens.ThePolycombgeneFIEisexpressed(blue)inunfertilizedeggcellsofthemossPhyscomitrellapatens(right)andexpressionceasesafterfertilizationinthedevelopingdiploidsporophyte(left).InsituGUSstainingoftwofemalesexorgans(archegonia)ofatransgenicplantexpressingatranslationalfusionofFIE-uidAundercontrolofthenativeFIEpromoter InthemossPhyscomitrellapatens,thePolycombproteinFIEisexpressedintheunfertilisedeggcell(Figure,right)asthebluecolourafterGUSstainingreveals.SoonafterfertilisationtheFIEgeneisinactivated(thebluecolourisnolongervisible,left)intheyoungembryo. [14] Otherorganisms[edit] Inalgae,theeggcellisoftencalledoosphere.[citationneeded]Drosophilaoocytesdevelopinindividualeggchambersthataresupportedbynursecellsandsurroundedbysomaticfolliclecells.ThenursecellsarelargepolyploidcellsthatsynthesizeandtransferRNA,proteins,andorganellestotheoocytes.Thistransferisfollowedbytheprogrammedcelldeath(apoptosis)ofthenursecells.Duringoogenesis,15nursecellsdieforeveryoocytethatisproduced.[15]Inadditiontothisdevelopmentallyregulatedcelldeath,eggcellsmayalsoundergoapoptosisinresponsetostarvationandotherinsults.[15] Seealso[edit] Egg Fertilization Insemination Menstrualcycle Ovabank Ovulation Polarbody Pollination Pregnancy Spawn(biology) References[edit] ^"OosphereMeaning|Best5DefinitionsofOosphere".www.yourdictionary.com.Retrieved2021-04-12. ^CobbM(2012)."Anamazing10years:thediscoveryofeggandsperminthe17thcentury".ReprodDomestAnim.47(Suppl4):2–6.doi:10.1111/j.1439-0531.2012.02105.x.PMID 22827343. ^""Conclusio"fromCarlErnstvonBaer'sDeOviMammaliumet..."(jpeg). ^Needham,Joseph(1959).AHistoryofEmbryology(2drevised ed.).Cambridge:CambridgeUniversityPress. ^Lopata,Alex(April2009)."HistoryoftheEgginEmbryology".JournalofMammalianOvaResearch.26(1):2–9.doi:10.1274/jmor.26.2.S2CID 86828337. ^White,YvonneAR(26February2012)."Oocyteformationbymitoticallyactivegermcellspurifiedfromovariesofreproductive-agewomen".NatureMedicine.18(3):413–421.doi:10.1038/nm.2669.PMC 3296965.PMID 22366948. ^Woods,DoriC(18April2013)."Isolation,characterizationandpropagationofmitoticallyactivegermcellsfromadultmouseandhumanovaries".NatureProtocols.8(5):966–988.doi:10.1038/nprot.2013.047.PMC 5545930.PMID 23598447. ^MassachusettsGeneralHospital."Egg-producingstemcellsisolatedfromadulthumanovaries".ScienceDaily.Retrieved28March2017. ^Regan,CarmenL.(2001)."Pregnancy".InWorell,Judith(ed.).EncyclopediaofWomenandGender:SexSimilaritiesandDifferencesandtheImpactofSocietyonGender,Volume1.AcademicPress.p. 859.ISBN 9780122272455.Retrieved2013-11-03. ^Alexander,Rachel;Davies,Mary-Ann;Major,Vicky;Singaram,S.Veena;Dale-Jones,Barbara(2006).X-kitAnatomy.PearsonSouthAfrica.p. 3.ISBN 978-1-86891-380-0. ^Alberts,Bruce;Johnson,Alexander;Lewis,Julian;Raff,Martin;Roberts,Keith;Walter,Peter(2002)."Eggs".MolecularBiologyoftheCell(4th ed.).NewYork:GarlandScience.ISBN 0-8153-3218-1. ^abc"TheOvum".Gray'sAnatomy.Retrieved2010-10-18. ^abEsau,K.(1977).Anatomyofseedplants(second ed.).NewYork:JohnWileyandSons.ISBN 978-0-471-24520-9. ^Mosquna,Assaf;Katz,Aviva;Decker,EvaL.;Rensing,StefanA.;Reski,Ralf;Ohad,Nir(2009)."RegulationofstemcellmaintenancebythePolycombproteinFIEhasbeenconservedduringlandplantevolution".Development.136(14):2433–2444.doi:10.1242/dev.035048.PMID 19542356. ^abMcCallK(October2004)."Eggsovereasy:celldeathintheDrosophilaovary".Dev.Biol.274(1):3–14.doi:10.1016/j.ydbio.2004.07.017.PMID 15355784. Externallinks[edit] TheOvarianKaleidoscopeDatabasedescriptionof1800genesinvolvedinovarianfunctions vteSexBiologicalterms Sexualdimorphism Male Female Sexualdifferentiation Feminization Virilization Sex-determinationsystem XY ZW XO ZO Temperature-dependent Haplodiploidy Heterogameticsex/Homogameticsex Sexchromosome Xchromosome Ychromosome Testis-determiningfactor Hermaphrodite Sequentialhermaphroditism Intersex parasexuality Sexasabiologicalvariable Sexualreproduction Evolutionofsexualreproduction Anisogamy Isogamy Germcell Reproductivesystem Sexorgan Meiosis Gametogenesis Spermatogenesis Oogenesis Gamete spermatozoon ovum Fertilization External Internal Sexualselection Plantreproduction Fungalreproduction Sexualreproductioninanimals Sexualintercourse Copulation Humanreproduction Lordosisbehavior Pelvicthrust Sexuality Plantsexuality Animalsexuality Humansexuality Mechanics Differentiation Activity  Sexportal vteHumanphysiologyofsexualreproductionMenstrualcycle Menarche Menstruation Follicularphase Ovulation Lutealphase Gametogenesis Spermatogenesis spermatogonium spermatocyte spermatid sperm Oogenesis oogonium oocyte ootid ovum Germcell gonocyte gamete Humansexualactivity Sexualarousal Sexualintercourse Masturbation Erection Orgasm Ejaculation Insemination Fertilization/Fertility Implantation Pregnancy Postpartumperiod Mechanicsofsex Developmentofthereproductivesystem Sexualdifferentiation Sexualdimorphism Feminization Virilization Puberty Gonadarche Tannerscale Pubarche Menarche Spermarche Adrenarche Maternalage /Paternalage Menopause Egg Ovum Oviposition Oviparity Ovoviviparity Vivipary Reproductiveendocrinologyandinfertility Hypothalamic–pituitary–gonadalaxis Hypothalamic–pituitary–prolactinaxis Andrology Hormone Breast Thelarche Development Lactation Breastfeeding Humanreproductivesystem Male Female Authoritycontrol:Nationallibraries France(data) Germany Israel UnitedStates Japan CzechRepublic Retrievedfrom"https://en.wikipedia.org/w/index.php?title=Egg_cell&oldid=1085330366" Categories:GermcellsCloningEggsHumanfemalereproductivesystemHumanfemaleendocrinesystemHiddencategories:ArticleswithshortdescriptionShortdescriptionisdifferentfromWikidataWikipediaarticlesneedingclarificationfromMay2021ArticlescontainingLatin-languagetextWikipediaarticlesneedingclarificationfromJuly2017AllarticleswithunsourcedstatementsArticleswithunsourcedstatementsfromOctober2014ArticleswithBNFidentifiersArticleswithGNDidentifiersArticleswithJ9UidentifiersArticleswithLCCNidentifiersArticleswithNDLidentifiersArticleswithNKCidentifiers Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk English Views ReadEditViewhistory More Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Languages AfrikaansAlemannischالعربيةAragonésঅসমীয়াAsturianuAzərbaycancaবাংলাBân-lâm-gúБеларускаяБеларуская(тарашкевіца)БългарскиBosanskiBrezhonegCatalàЧӑвашлаČeštinaChiShonaDanskDeutschEestiΕλληνικάEspañolEsperantoEuskaraفارسیFrançaisGaeilgeGalegoગુજરાતી𐌲𐌿𐍄𐌹𐍃𐌺한국어Հայերենहिन्दीHrvatskiBahasaIndonesiaInterlinguaÍslenskaItalianoעבריתJawaಕನ್ನಡҚазақшаKiswahiliKurdîКыргызчаLatinaLatviešuLietuviųМакедонскиമലയാളംمصرىBahasaMelayuNederlands日本語NorskbokmålNorsknynorskOccitanଓଡ଼ିଆOʻzbekcha/ўзбекчаPolskiPortuguêsRomânăRunaSimiРусскийSimpleEnglishSlovenčinaSlovenščinaکوردیСрпски/srpskiSrpskohrvatski/српскохрватскиSundaSuomiSvenskaTagalogதமிழ்Татарча/tatarçaไทยTürkçeУкраїнськаTiếngViệtWinaray吴语粵語中文 Editlinks