Lesi sigaba sokuqala senqubo yokuzala sifushane
I-zygote iyinyunyana ye-sperm cell kanye ne-egg cell. Eyaziwa nangokuthi i-ovum ekhulelwe, i-zygote iqala njengeseli elilodwa kodwa ihlukanisa ngokushesha ezinsukwini ezilandelayo ukukhulelwa. Emva kwalesi sikhathi sesonto lamabili sesigaba se-cell, i-zygote ekugcineni iba umbungu. Uma lokhu kuhamba kahle, umbungu uba umntwana.
Zygotes Ifomu?
Ukuze kube nokukhiqiza, isisodwa segciwane lesisu kufanele singene ngaphakathi kweqanda.
Ezimweni eziningi, iqanda elilodwa likhishwa ngesikhathi sesigaba sokuvuthwa komjikelezo wonyaka wokuzala wesifazane. Ngokuvamile, izinkulungwane zemizamo yomuthi yokungena kuleli qanda elilodwa lamaqanda. Uma isidoda esisodwa siphumele ngaphandle, ukushintsha kwamakhemikhali ebusweni beqanda kuvimbela ezinye izidakamizwa ukungena.
Le nqubo ngokuvamile iyenzeka ngesikhathi sokulala ngokocansi, nakuba ukukhulelwa ngomuthi kungasiza. I-intrauterine insemination (IUI) ne-in vitro fertilization (IVF) yizindlela ezimbili ezivame ukusizwa ngezindlela zokuzala.
Ngesikhathi se-IUI, isilwane sifakwa esibelethweni besebenzisa i-catheter ukuze ukukhulelwa kwenzeke ngaphakathi komzimba wesifazane. Ku-IVF, amaqanda asuswe kuma-ovari futhi ahlwanyelwe ebhodini. I-zygote isetshenziselwa isisu.
Kwenzekani Ngemuva Komanyolo?
I-zygote ihlukanisa ngenqubo eyaziwa njenge-mitosis, lapho iseli ngalinye liphindwe kabili ngokuhlukanisa ngamaseli amabili.
Lesi sigaba seviki ezimbili siyaziwa njengenkathi yokuhluma kwemvelo futhi ihlanganisa isikhathi sokukhulelwa ekufakweni kombungu embelethweni.
Ezimweni eziningi, iseli ngalinye lesilisa nesilisa liqukethe ama-chromosomes angu-23. I-sperm cell iqukethe ulwazi lofuzo oluvela kubaba ngenkathi i-egg cell iqukethe ukwaziswa kofuzo oluvela kumama.
Ngenxa yokuthi iseli ngalinye liqukethe isigamu sezinto eziphathekayo zofuzo, iseli ngalinye liyaziwa ngokuthi iseli le-haploid.
Lapho lawa ma-cell amabili angama-haploid ejoyina, enza iseli elilodwa le-diploid eliqukethe ama-chromosomes angu-46. I-zygote ihambela phansi ithubhu ye-fallopian kuya esibelethweni lapho kufanele ibeke khona emgodini ukuze ithole ukudla okumele kukhule futhi kuqhubeke.
Uma le nqubo ihamba kahle, i-zygote izoqhubeka ikhula kuze ifinyelele esigabeni esilandelayo sokuthuthukiswa kokubeletha.
Isigaba Zygote Siphelile Kangakanani?
Inkathi ye-zygote imfushane kakhulu, ihlala cishe izinsuku ezine. Ngosuku lwesishiyagalombili, ubukhulu bamaseli bubizwa ngokuthi i-blastocyst. Isikhathi segciwane sizohlala cishe izinsuku eziyishumi nane, emva kwalokho i-embryonic period izoqala.
Inkathi yesibili yentuthuko ivela emavikini amabili emva kokukhulelwa ngeviki lesishiyagalombili, ngesikhathi lapho umzimba uwaziwa ngokuthi umbungu. Ngesonto lesishiyagalolunye emva kokukhulelwe, isikhathi sokubeletha siqala. Kusukela kuleli phuzu kuze kube sekuzalweni, umzimba uyaziwa ngokuthi ungumntwana.
Akuwona wonke ama-zygotes akwenza esigabeni esilandelayo sokuthuthukiswa kokubeletha, noma kunjalo. Abacwaningi balinganisela ukuthi amaphesenti angama-30 kuya kwangu-70 azo zonke izimo ezenzeka ngokwemvelo ahluleka noma ngaphambili ngesikhathi sokufakelwa .Umthombo:
> Imithombo:
> Niakan, K., et al "Ukuthuthukiswa komuntu kwangaphambi kokugxila embuthweni." Ukuthuthukiswa kukaMashi 2012