Miyeso ya chitukuko cha mwana wosabadwa

Pambuyo pa sabata lachisanu ndi chitatu la mimba, khanda limayamba, ziwalo zake zimayikidwa, ndipo patapita nthawi mwanayo amakhala ndi ziwalo zonse, ndipo kenako chitukuko chawo chimachitika. Nthawi yopitirira masabata asanu ndi atatu amatchedwa embryonic, ndipo patatha masabata asanu ndi atatu sichilinso khanda, koma mwana amatha msinkhu.

Miyeso yoyamba ya chitukuko cha mwana wosabadwa

Maseŵera oyambirira a kukula kwa mluza angayambike ndi tsiku. Pa tsiku loyamba dzira lomwe lili mu falsipian chubu limakumana ndi umuna ndi siteji yoyamba - umuna umachitika. Ndipo tsiku lotsatira gawo la zygote liyamba - selo lomwe liri ndi nuclei mumapangidwe ake ndi makina a haploid a chromosomes, mutatha kusanganikirana komwe khungu limodzi ndi khungu la dipromoside limapangidwa.

Tsiku lotsatira, selo likuyamba kugawa - siteji ya morula kapena kupweteka kumayamba, kutenga masiku 4. Selo lirilonse limagawanika mpaka mzere umodzi wa maselo okhala ndi mpanda mkati mwa blastula umapangidwa. Kuchokera m'maselo ake m'tsogolomu anapanga trophoblast (placenta yamtsogolo) ndi embryoblast (mwana wamtsogolo).

Pa tsiku lachisanu ndi chiwiri blastula imalowetsa mu chiberekero, komwe imayamba kuyambitsa mavitamini omwe akufunikira kuti ayambe kutsogolo - kumayambira m'mimba , yomwe imatenga masiku awiri.

Embryo mutatha kuikidwa

Kukhazikitsa kumene kumapangitsa gawo lotsatira la kukula kwa mluza - gastrula. Mbalame imodzi yokha ya embryoblast maselo imasanduka mpira wosanjikizana. Chinyezi chamkati chimatchedwa ectoderm ndipo chimapangitsa epithelium khungu ndi ziwalo za mitsempha. Iyi ndi gawo la kusiyana kwa mapepala a embryonic.

Kuchokera kumbali yowonjezera (endoderm) m'tsogolo, zilembo zonse za m'mimba za m'mimba (m'mimba, matumbo, bronchi ndi mapapu), komanso chiwindi ndi kapangidwe. Zigawo ziwirizi zikugunda, kupanga ma thovu (amniotic - mtsogolo amniotic fluid ndi yolk - choyamba kudyetsa mimba, ndiyeno ngati chiwalo cha thupi).

Kuyambira nthawi ino (yomwe imatha kumayambiriro kwa sabata lachitatu la mimba), gawo lotsiriza la chitukuko cha embryo - organogenesis - chimayamba.

Posakhalitsa izi, mimba imathamangira, ectoderm yake imayika pamphuno kuchokera kunja, ndipo kumapeto kwa mkati kumalowa mkati mwa chubu ndikupanga matumbo oyambirira. Mimbayo imakhala yosasunthika kuchoka ku zigawo zina zapadera. Pakati pa amniotic ndi yolk sac, chimbudzi china chimakhazikitsidwa - mesoderm, chomwe chidzapangitsa mafupa ndi minofu ya mwanayo.

Pambuyo pa masabata 4, ziwalo zamkati za mwanayo zimayamba kuikidwa. Pa sabata lachisanu ndi chimodzi, ziwalo za miyendo ziwonekera, mpaka kumapeto kwa 7, mtima ndi zipinda zake zimapangidwira, mpaka mapangidwe a ziwalo zonse zamkati, mapapo, ndi ziwalo zowononga zimatha. Pambuyo pa sabata 9, ziwalo zonse ndi machitidwe adakhazikitsidwa kwathunthu, ndipo pokhapokha kusiyana kwawo kudzachitika.