Halitta yana faruwa ne lokacin da namijin jima'i (kwayar jini) ya shiga cikin jikin mace kuma ya haɗu da kwayar kwai. A sakamakon haka, an kafa sabuwar cell (zygote) da kuma samuwar amfrayo na mutum. Sai kawai a farkon makonni takwas na ci gaba na intrauterine, an kira jaririn tayin ko amfrayo. A nan gaba an kira shi 'ya'yan itace.
A cikin makonni takwas na farko, an kafa manyan gabobin, ciki da waje,. Ta hanyar bayyanar amfrayo, ba tukuna ba zai yiwu don sanin jima'i na amfrayo - zai zama mai yiwuwa bayan bayan makonni biyu.
Matsayin ci gaba na amfrayo na mutum
Bari mu gano yadda tsarin ci gaban mutum ya faru. A lokacin hawan, akwai nau'i biyu a cikin kwai. Lokacin da suka haɗu, an kafa embryo na unicellular, wanda ake hada da 23 chromosomes na mahaifinsa zuwa 23 chromosomes na mahaifiyar. Sabili da haka, saitin chromosomes a cikin tarin amfrayo yana da guda 46.
Bayan haka, amfrayo na mutum zai fara tafiya cikin motsi tare da bututun falfin a cikin mahaifa. A cikin kwanaki hudu na farko, fission daga cikin sel na amfrayo ya faru kamar sau ɗaya a rana, a nan gaba kwayoyin zasu fara rabawa da sauri.
Duk wannan lokacin mahaifa yana shirye-shiryen daukar tayin, mucosa ya zama karami kuma ƙarin jini yana bayyana a cikinta. Kusan a rana ta bakwai bayan an fara samuwa embryo hawan, wadda ta kai kimanin awa 40. Vorsels a farfajiya na amfrayo ya karu kuma yayi girma a cikin nau'in mahaifa. An halicci mahaifa.
A karshen mako na biyu, tsawon jima'iyar mutum zai kai kimanin miliyon 1.5. Kusa da mako huɗu, kafawar mafi yawan kwayoyin halitta da kyallen takalma - farawa na guringun kafa na kwarangwal, kasusuwa, kodan, hanji, hanta, fata, idanu, kunnuwa kunnuwa.
A mako biyar na tsawon amfrayo ya riga ya kai kimanin 7.5 millimeters. Tare da taimakon duban dan tayi a wannan lokaci, wanda zai iya lura da yadda zuciyarsa ke takawa.
Da farko da kwanaki 32, amfrayo na mutum yana da ginshiƙan hannayensu, kuma mako guda daga baya - ginshiƙan ƙafafu. Lokacin da makon takwas na ci gaba ya ƙare, amfrayo yana da tsawon lokaci a yankin 3-4 cm. Dukansu tsarin ciki na amfrayo da bayyanar ta waje sun sayi duk alamun mutum. Tsarin dukkan gabobin jiki ya ƙare.
Abubuwan da ke shafi ci gaba da amfrayo
Shan taba
Nicotine iya sauƙaƙe jaririn a cikin mahaifa, saboda tayin a cikin watanni biyu na farko yana da damuwa da rashin isashshen oxygen, kuma lokacin shan taba shi ba zai yiwu ba.
Barasa
Rinjayar barasa a kan ci gaba da amfrayo bai zama mara kyau ba. Alal misali, shan a lokacin zanewa zai iya haifar da ciwo na embryo, wanda aka bayyana a cikin mawuyacin halin da ake ciki. Yana da haɗari sosai har ma yin amfani da barasa, idan yana faruwa a lokacin dasawa ko kuma samuwar kwaya. Ci gaba da ciwo na barasa yana haifar da sakamako a kan amfrayo na barazanar ethyl, wanda zai haifar da raguwa a cikin ci gaban jiki, cin zarafin CNS, abubuwan da ke cikin fuska da na ciki.
Drugs
Sakamakon kwayoyi a kan tayin yana bayyana a rage jinkirin ci gaba, ciwo mai yawa na ci gaba, cututtuka masu rikitarwa marasa kyau, mutuwar intrauterine. Sau da yawa akwai lokutan haihuwa da ke haifar da ƙaddamar da ciwon miyagun ƙwayoyi cikin jikin yaron.
Radiation
Jariri na jariri yana mai saukin kamuwa da radiation. Rigarar da mahaifiyar kafin lokacin da aka fara yin gyare-gyare na ƙafa, ya hada da mutuwar amfrayo. Idan radiation cutarwa ta shafi lokacin embryogenesis, ƙwayoyin cuta da ci gaba na ci gaba da ci gaba, yiwuwar mutuwa ta ƙara.