Yini ingane ibukeka ngayo amaviki angu-5?
Ngeviki lesihlanu lokuthuthukiswa kwamabriyoni, umntwana ufana ne-tadpole isikhathi. Ubude bomzimba wakhe esikhathini esinikeziwe cishe cishe akudluli 2 mm. Nokho, naphezu kokulingana okuncane, inhliziyo ye-embryo ngalesi sikhathi isivele iqalile ukwehla. Kukhona ukuvuselelwa kokuthuthukiswa kweziningi ezingaphakathi zangaphakathi kwezingane ezingakazalwa. Futhi, izici zobuso ziqala ukwakha, futhi ngokubukeka zibukeka zifana nomuntu omdala. Ngakho-ke, sekuvele kungenzeka ukuhlukanisa amakhanda, izingxenye eziyinhloko zamehlo athuthukayo ezizwela kakhulu emisebeni elula.
Iziphi izinguquko ezenzeka emzimbeni wombungu ngesonto 5?
Ukuthuthukiswa kwe-fetus evikini lesi-5 lokukhulelwa kuyaqhubeka nokwakhiwa kwezitho ze-extraembryonic, ezibhekele ukusekelwa okuvamile kokuphila, ngenkathi zisengumbungu. Ngakho okokuqala ezinye i-villi ye-chorion zaziyi-protrusions elula, futhi manje ngayinye yazo ihlumela ama-capillary. Ngemva kwalokho, ingane iqala ukudla hhayi ngokubhubhisa amangqamuzana omzimba ayimzungezayo, kodwa uthola zonke izakhi ezidingekayo ezivela kunina. Yigazi lowesifazane okhulelwe oyoletha zonke izakhi eziwusizo kumntwana, ukugeza i-villus ye-chorion. Ngenxa yezinguquko ezinjalo, ngesonto le-5 lokuthuthukiswa kombungu, ukujikelezwa kwegazi kwe-utero-placental kuhlelwe.
Eyakhelwe kulolu suku, i-placenta eyinhloko ithathwa njengomsebenzi.
Yonke imisebenzi engenhla iqala ukukhula ngeviki lesihlanu lokukhulelwa futhi iqhaza ekuthuthukiseni ingane. I-placenta ayisakwazi ngokugcwele ukuvikela umbungu kusuka emathonyeni angaphandle angozi. Yingakho le nkathi yokuzala izithandani ze-fetus ibizwa ngokuthi yi-critic, tk. kukhona amathuba aphezulu okukhipha isisu.