Yintoni ibonakala ngathi umntwana usondele kwiiveki ezi-5?
Ngeveki yesihlanu yokuphuhliswa kwamathumbisi, umntwana unjengengqungquthela ngexesha. Ubungakanani bomzimba wakhe ngexesha elithile liphantse lize lingadluli kwi-2 mm. Nangona kunjalo, naphezu kobuncinci obuncinane, intliziyo yesibindi ngeli xesha sele iqalile ukuhla. Kukhona ukuqaliswa kokuphuhliswa kwezona zinzulu zangaphakathi zomntwana ongakazalwa. Kwakhona, iimpawu zobuso ziqala ukwenza, kwaye ngokubonakala ngathi zifana nomntu omdala. Ngaloo ndlela, sele kusenokwenzeka ukuba ukwahlula amacenge, iinxalenye eziphambili zamehlo eziphuhliso ezinokukhathazeka kakhulu kumbane okhanya.
Ziziphi utshintsho ezenzeka emzimbeni webridi ngeveki 5?
Ukuphuhliswa komntwana kwiveki yesi-5 yokukhulelwa kuyaqhubeka kunye nokwakhiwa kwamalungu e-extraembryonic, enoxanduva lokuxhaswa kwezinto eziqhelekileyo zokuphila, ngelixa sisengumntwana. Ngoko okokuqala i-villi ye-chorion yayimilenze elula, kwaye ngoku nganye ihluma i-capillary. Emva koko, umntwana uqala ukungadli ngokutshabalalisa iiseli zeethambo ezizungezile, kodwa ufumana zonke izondlo ezifunekayo kunina. Yigazi lomfazi okhulelweyo oza kuzisa zonke izinto ezincedo kumntwana, uhlambe i-villus ye-chorion. Ngenxa yolu tshintsho, kwiveki yesi-5 yokuphuhliswa kwembungu, ukujikelezwa kwegazi ye-utero-placental ihlelwe.
Eyilungiselelwe kulo mhla, i-placenta ephambili ithathwa ngomsebenzi.
Yonke le misebenzi ingentla iqala ukuhluma kwiveki yesi-5 yokukhulelwa kwaye ifake isandla ekuphuculeni phambili komntwana. I-placenta ayikakwazi ngokupheleleyo ukukhusela umbungu kwiimpembelelo zangaphandle zingozi. Yingakho le nkqubo yokuzala izithinteli zokubeletha kuthiwa ibaluleke kakhulu, i-tk. kukho ubukhulu obuphezulu bokukhipha isisu.