Ukucubungula kwenzeka lapho isilwane sesilisa (isilwane esitokisini) singena emzimbeni wesifazane futhi sihlangene neqanda layo seliqanda. Ngenxa yalokho, kwakhiwa iseli elisha (zygote) futhi ukwakheka kombungu womuntu kuqala. Kuphela kwamasonto ayisishiyagalombili okuqala okuthuthukiswa kwe-intrauterine, ingane ibizwa ngokuthi i-fetus noma i-embryo. Esikhathini esizayo libizwa ngokuthi izithelo.
Emasontweni ayisishiyagalombili okuqala, izitho ezisemqoka, zombili zangaphakathi nangaphandle, zibekiwe. Ngokubukeka kwe-embryo, akukakakhona ukucacisa ubulili bombungu - kuzokwenzeka kuphela emva kwamanye amasonto amabili.
Izindlela zokuthuthukiswa kombungu womuntu
Ake sihlole ukuthi ukuthuthukiswa kwamabriyoni kwenzeka kanjani. Ngesikhathi sokukhulelwa, kunama-nuclei amabili emaqanda. Uma behlangana, i-embryo e-unicellular yakhiwa, lapho ama-chromosomes angu-23 kababa ayengezwa kuma-chromosomes angu-23 omama. Ngakho-ke, isethi yama-chromosomes esitokisini se-embryo yizingcezu ezingu-46.
Okulandelayo, umbungu womuntu uqala kancane kancane ukuhamba nge-tube fallopian kuya esibelethweni. Ezinsukwini ezine zokuqala, i-fission yamaseli embungu ivele cishe kanye ngosuku, esikhathini esizayo amaseli aqala ukuhlukanisa ngokuphindaphindiwe.
Konke lokhu lesi sibeletho silungiselela ukuthatha i-fetus, i-mucosa yayo iba nemithwalo yegazi eyandayo futhi eyengeziwe evele kuyo. Cishe ngosuku lwesikhombisa emva kokuqala kokukhulelwa kwe-embrying embryo, okuhlala cishe amahora angu-40. I-Vorsels ebusweni bombungu uyanda futhi ikhule ibe izicubu zesisu. I-placenta idalwe.
Ekupheleni kwesonto lesibili, ubude bombungu wesintu bufinyelela kumamitha ayi-1.5. Ngasekupheleni kweviki lesine, ukwakheka kwezitho eziningi kanye nezicubu ziqala - ama-cartilage ama-skeleton, amathambo, izinso, amathumbu, isibindi, isikhumba, amehlo, izindlebe zivela.
Ngeviki lesihlanu ubude bombungu usuvele buba ngamamitha angu-7.5. Ngosizo lwe-ultrasound ngalesi sikhathi, umuntu angabona ukuthi inhliziyo yakhe iyancipha kanjani.
Kusukela ezinsukwini ezingu-32, umbungu womuntu unamaphutha ezandla, futhi ngemva kwesonto - izinyawo zezinyawo. Lapho isonto lesishiyagalombili lokuthuthukiswa liphela, umbungu uthola ubude esifundeni sesentimitha 3-4. Kokubili isakhiwo sangaphakathi se-embryo nokubonakala kwayo kwangaphandle kuthola zonke izimpawu zomuntu. Ukubethelwa kwazo zonke izitho ezisemqoka kuphelile.
Izinto ezithinta ukuthuthukiswa kombungu
Ukubhema
I-Nicotine ingakwazi ukuphoqa kalula umntwana esibelethweni, ngoba ingane ehamba ezinyangeni ezimbili zokuqala izwela kakhulu ngokuntuleka kwe-oxygen, futhi uma ukubhema kungenakugwema.
Utshwala
Ithonya lokuphuza utshwala ekuthuthukiseni umbungu akuyona into embi kakhulu. Isibonelo, ukuphuza ngesikhathi sokukhulelwa kungaholela ekudakwa komzimba we-embryo syndrome, okuvezwa ngamaphutha amaningi okuthuthukisa. Kuyingozi kakhulu ngisho nokusetshenziswa kokwephuza ngokweqile, uma kwenzeka ngesikhathi sokufakelwa noma ukubunjwa kwesitho. Ukuthuthukiswa kotshwala we-alcohol kubangelwa umphumela embryo we-ethyl alcohol, okuholela ekunciphiseni ukukhula komzimba, ukwephulwa kwe-CNS, ukukhubazeka kobuso kanye nezitho zangaphakathi.
Izidakamizwa
Umthelela wezidakamizwa ebusweni ubonakala ekunciphiseni kwentuthuko, ukukhubazeka okuningi okuthuthukiswa, ukuphazamiseka kokukhathazeka kokuzalwa, ukufa kwe-intrauterine. Kukhona izikhathi eziningi zokubeletha ezibangelwa ukuphela kokudla izidakamizwa emzimbeni wengane.
Umswakama
Umbungu wengane usuke unomthelela kakhulu emiphumeleni yemisebe. Ukuqothula umama ngaphambi kokuqala ukufakwa kwesigqila sesisu, kuhlanganisa ukufa kombungu. Uma imisebe eyingozi ingathinta isikhathi se-embryogenesis, izimo eziphuthumayo kanye nezinkinga zokuthuthukiswa zikhula, amathuba okufa kwawo akhula.