Mhlawumbe, esinye sezibonakaliso ezinkulu kunazo zonke emhlabeni ukuzalwa impilo entsha. Izidalwa ezimbili eziphilayo zihlangene ekukhuliseni, ukuze ziqhubeke nezakhi zazo futhi zinike indlalifa izimfanelo zabo ezinhle kakhulu. Kungenxa yokuthi zonke izinto eziphilayo emhlabeni wethu zizama. Masikhulume kulesi sihloko mayelana nokuthi ukukhulelwa kweqanda kwenzeka kuphi.
Kukuphi ukukhulelwa okwenzeka kubantu?
Lowo mzuzu omangalisayo lapho i-ovum ne-spermatozoon iba yinye, imfihlo encane. Ukufakelwa komuntu kubantu kubonakala emgqonyeni womama womama, lapho i-spermatozoa ihlangabezana nezinselele ezihlukahlukene. Amaseli wesilisa kumele ahambe ngendlela elukhuni, okuyilapho kuphela okungu-1% kubo abayosinda, kodwa bayoba abameleli abasebenza kakhulu, bephethe izimfanelo ezinhle zezingane ezizayo. Abasindile abaningana abaye bafika endaweni lapho ukukhulelwa kwenzeka khona kumele banqobe ukuvikelwa okukhenywe kweqanda, futhi umuntu oyedwa onenhlanhla uyophumelela. Ngokomthetho wemvelo, onamandla kunawo wonke asinda lapha.
Ukuzalwa kokuphila okusha
I-tube fallopian ithola ama-ovari kuphela ovule ngesikhathi esisodwa. Iseli kumele liqhubeke nelinye lama-tubes. Imvelo ihlelwe konke ngendlela yokuthi esigabeni ngasinye sokuvela komuntu omusha ukhetha ukunikeza ingane kuphela okungcono kakhulu. Kuze kube yizinsuku ezinhlanu, uhambo lokuphila esikhathini esizayo luzohlala luze lufinyelele endaweni lapho inqubo yokukhulelwa ifaka khona. Lapha kuphela i-spermatozoon engena kwinucleus yeqanda, ndawonye iyakha i-zygote - iselula encane kodwa ebaluleke kangaka, efaka ukubonakala komntwana. Yiqiniso, le seli seluthola ngokushesha isivikelo esisha, sinamandla nakakhulu kunegobolondo langaphambilini, ukukhipha ngokuphelele amathuba okuthonya amanye amaseli wesilisa ku-zygote.