Sezvo mutemo, zvinenge zvakaoma kufungidzira apo mazai akange awedzerwa, saka kutanga kwepamuviri kunotanga kuverenga kubvira pazuva rakutanga kwekupedzisira kwekuenda kumwedzi.
Fertilization
Kubvira panguva ino inotanga kuumbwa uye kuve nekutsvaga kwemai. Mushonga wayo unowanikwa mukati memavhiki maviri kusvika maviri.
Pamberi pemasero ekuberekwa kwevarume nevakadzi, zvinotora maawa 3-6. Vakawanda vanonzi spermatozoa, vachienda kumazai, vanosangana nenzira yavo zvipingamupinyi zvakawanda, semugumisiro, ndiyo chete spermatozoa ine simba zvikuru inoenda kune chinangwa. Asi mumwe chete wavo achabatanidzwa mukugadzirwa kwehutano.
Apo spermatozoon inokunda kupfeka kweii, pakarepo muviri wemukadzi unotanga kuvakazve basa rawo, izvo zvino zvichatarirwa kuchengetedza pamuviri.
Muchigadzirwa chekudyara, sero idzva rine genetic code, iyo ichagadzirisa hupombwe hwomwana, maitiro ayo e nzeve, ruvara rwemaziso nezvimwe zvinhu, rinoumbwa kubva kumasero evabereki vaviri, rimwe nerimwe rine hafu yechromosomes imwe neimwe.
Pazuva rechina -5, mazai anogadzirwa anosvika pachibereko. Nenguva ino, iri kutotanga kuve mumumvuri unenge anenge masero zana.
Kuiswa mumadziro emuviri kunowanikwa pakutanga kwevhiki rechitatu. Mushure mokunge mimba iyi yapera. Kufambira mberi kwechibereko uye kusungirirwa kumadziro ayo ndicho chiitiko chinotyisa chekukura kwe fetus mumwedzi wokutanga.
Kugadzirwa kwe fetus
Mwedzi wokutanga mushure mekuguma kwekugadziriswa kwemaitiro, kushandiswa kwema fetal maitiro kunotanga. Mutsara unotanga - ramangwana rakapera, amnion - inofananidzira ye fetal bladder uye umbilical cord. Kubudirira kwema fetus mumwedzi wokutanga wekuita pamuviri kunotanga nekuumbwa kwemashizha matatu embryonic. Mumwe nomumwe wavo anomiririra mucheche wezvikamu zvakasiyana uye matukisi.
- Girazi rekumakristoni rekunze ndiro runyoro rwehurongwa hwemagetsi, meno, ganda, nzeve, epithelium yemaziso, mhino, misumari nemvere.
- Iyo mapeji emashizha ari pakati anoshumira sechikonzero chechirwere (masaga emasumbu, nhengo dzomukati, musana, goroti, midziyo, ropa, lymph, glands zvepabonde).
- Girazi remukati re embryonic rinoshanda sechikonzero chekugadzirwa kwemukasi memuviri wemhepo yekufema, zvikamu zvemuviri wepamuviri, chiropa uye pancreas.
Pakupera kwemwedzi mumwe wekudzivirira, fetus (embryo) inenge iine urefu hwemamiriyoni 1 (embryo inoratidzika kune ziso rakashama). Pane bhukitiro rechidimbu - ramangwana repine. Pane bhukitikiti yemwoyo uye kuonekwa kwemidziyo yekutanga yeropa.