Ngaphambi kweveki ye-8 yokukhulelwa, i-embrayo iyaqhubeka, izitho zayo zibekwa, kwaye emva kwexesha eli limbungu linamalungu amakhulu, kwaye ke kuphela ukuphuhliswa kwabo kwenzeka. Ixesha elide ukuya kwiiveki eziyi-8 libizwa ngokuba yi-embryonic, kwaye emva kweveki ezi-8 akusekho umbungu, kodwa i-fetus, kunye ne-fetus period iqala.
Amanqanaba okuqala okuphuhliswa kombungu womntu
Amanqanaba okuqala okuphuhliswa kombindi angalandelwa ngumhla. Ngomhla wokuqala iqanda kwi-tube fallopian idibana ne-sperm kunye nesigaba sokuqala-ukuchumisa kwenzeka. Ngomso olulandelayo isigaba se-zygote siqala-iseli esinama-nuclei e-2 kwinqanaba le-haploid ye-chromosomes, emva kokuxubusha kweeseli kunye nenethi ye-chromosome ye-diploid.
Ngomhla emva kwalokhu, iseli iqalisa ukwahlula - isigaba se-morula okanye ukuchotshoza kuqala, kuthatha iintsuku ezi-4. Iselinye ngasinye sihlulwe kuze kube yilapho ibhola elilodwa lendawo yeeseli elinomtya ngaphakathi kwe-blastula lenziwa. Ukusuka kwiiseli zayo kwixesha elizayo elenziwe i-trophoblast (i-placenta ezayo) kunye ne-embryoblast (umntwana ozayo).
Ngomhla wesi-7 i-blastula ingena kwisibilini sesibindi, apho iqala ukukhupha i-enzymes efunekayo ekuqaleni kwesigaba esilandelayo- ukufakelwa kwembungu , ehlala kwiintsuku ezi-2.
Embryo emva kokufakelwa
Ukufakela nje ukuvelisa kuphakama kwisigaba esilandelayo sokuphuhliswa kombungu - gastrula. Ibhola elilodwa lendawo ye-embryoblast iseli lijika libe ibhola elincinane. Uluhlu lwangaphandle lwama-embryonic lubizwa ngokuba yi-ectoderm kwaye lunikeza i-epithelium yesikhumba kunye namalungu enkqubo ye-nervous. Esi sisigaba sokwahlukana kwamaphepha e-embryonic.
Ukusuka kwinqanaba langaphandle (endoderm) kwixesha elizayo, zonke izembozo ze-epithelial zeengaphakathi zangaphakathi zesisu (isisu, intlungu, i-bronchi kunye nemiphunga), kunye nesibindi kunye ne-pancreas. Ezi zimbini zibophe, zenze iimbumba (amniotic - i-future amniotic fluid kunye ne-yolk - kuqala ukunyusa umbungu, kwaye ke njengelungu le-hemopoietic).
Ukususela kulo mzuzu (ophelela ekuqaleni kweveki yesithathu yokukhulelwa), isigaba sokugqibela sophuhliso lwe-embryo - organogenesis - siqala.
Kungekudala ngaphambi koku, i-curly curves, i-ectoderm yayo ibeka umbungu ngaphandle,
Emva kweveki ezi-4, izitho zangaphakathi zomntwana ziqala ukufakwa. Ngeveki yesi-6, izakhiwo zeemilenze ziya kubonakala, de kube sekupheleni kwe-7, intliziyo kunye namagumbi ayo awakhiwe, de kube kusetyenziswe zonke izitho zangaphakathi, imiphunga kunye nezitho zangasese. Ngeveki 9, zonke izitho kunye neenkqubo zenziwe ngokusisiseko, kwaye ke kuphela ukuhlukana kwabo kuya kwenzeka.