Usati wabereka mwana
Ndeipi chiratidzo chekutanga kwebasa hazvizivikanwi, asi pane zvakawanda zvinokonzera kutanga kwekukurumidza kwezviitiko zvinokonzera kuberekwa kwe fetus. Nhamba yeprogesterone, yakazara ne-placenta muropa raamai, inosvika pakakwirira kwayo isati yasunungurwa. Progesterone ndiyo hormone inotarisira kuchengetedza pamuviri. Iine mhedziso yekuzorodza pamushonga unotapira wechibereko.
Hormonal zviratidzo
Pedyo nokuguma kwepamuviri, intrauterine nzvimbo zvishoma nezvishoma inopera, uye oxygen kutora kumucheche inopera zvishoma nezvishoma (iyo placenta haigoni kusangana nezvido zvekukura kunowedzera nokukurumidza). Izvi zvinokonzera kuwedzera kuvharidzira kweAdrenocorticotropic hormone (ACTH) mumutambo wekare we fetal pituitary gland. ACTH inokurudzira adrenal cortex, iyo inovhara glucocorticoids, iyo inokonzera kukanganisa kunogadzirisa kuchengetedzwa kweprogesterone muparcenta. Panguva imwecheteyo, uwandu hwewesrogen hunogadzirwa ne-placenta unova mukuru, unofambidzana nekuonekwa pamasero emasumbu emuviri wechibereko chei oxytocin (chibereko chinowedzera kuwedzerwa ne oxytocin).
Skirmishes
Zvishoma nezvishoma, iyo inhibitory effect ye progesterone pamasero masero anokonzerwa nemubereki inodzvinyirirwa nekuwedzera kunokonzera simba revenrogen. Muchembera anotanga kunzwa manzwiro ekutanga asina simba akasiyana-siyana emakumbo, anonzi Braxton-Hicks zvinopesana. Zvinobatsira pakugadzirisa kwechirwere pakugadzirira kuberekwa kwemwana uye kazhinji kunokanganisa mudzimai semutambo wokuberekwa. Pakupera kwekuita pamuviri, chirwere chechiberekedzo chinogadziriswa chinokonzera amai ve hypothalamus (brain area), iyo inoita kuti pituitary ibudise hormone oxytocin. Iyi hormone inoberekawo mamwe fetal cells. Apo nhamba ye oxytocin inowedzera, iyo placenta inotanga kugadzira prostaglandin, iyo inobatanidzwawo muzvipembenene zveuite.
Kusimbisa kwezvinyorwa
Sezvo chibereko chinowedzera kuoma oxytocin, zvipembenene zvinowedzera zvishoma uye zvinowedzera. Kurwisana kunogara kwakasimba kunoratidza kutanga kwebasa. Sezvo zvinopesana zvinowedzera, maitiro akanaka anopa maitiro anoita kuti kuwedzerwa kwekushandiswa kwe oxytocin, iyo inotungamirira kune mamwe maitiro akawandisa emuviri. Iyi nzira inoguma kushanda mushure mekusununguka, apo chivharox chinoguma kutambanudzwa. Iyo nzira yekuberekwa inopatsanurwa muzvikamu zvitatu: kuvhura kwechirwere, kubviswa kwe fetus uye kuberekwa kwepentecenta.
Kuzivisa
Kumusoro wemwana wacho aigona kupfuura nomugero wekuberekwa, chirwere chechivharo uye chirwere chechikadzi chinofanira kutambanudzika kusvika anenge masendimita gumi paupamhi. Kuberekwa kunotanga nekusawirirana kusina simba kwepamusoro kune chikamu chepamusoro chechibereko. Izvi zvishoma zvinotapudzwa zvinopera anenge masere 10-30 panguva dzenguva dzemaminitsi gumi nemashanu. Sezvo basa racho richifambira mberi, zvipfeko zvinowanzova zvakanyanya uye zvakasimba uye zvishoma nezvishoma zvinosvika kune chikamu chepasi chechibereko. Musoro wemubhedha wemakwenzi anosvika kumuromo wechibereko chechiberekero pamakumbo ose, izvo zvinoita kuti kugadzirisa uye kuvhara zvishoma. Pane imwe nguva, membrane yemamniotic iyo inodzivirira fetus panguva yekuzvitakura, uye kuputika kweamniotic fluid, inoputsika.
Kuisa
Nguva yekuzarura ndiyo nzvimbo yakareba kwazvo yebasa, inogara kubva maawa 8 kusvika ku24. Muchikamu chino, fetus inotanga rwendo rwayo parugwaro rukuru, panguva imwe chete ichiita zera. Pakupedzisira, musoro unowanikwa mumakoko maduku eamai. Chikamu chechipiri chebasa chinotanga kubva pakuzarurirwa kwakakwana kwomukatikiti kusvikira panguva yekuzvarwa chaiye kwemucheche. Nekuzarurirwa kwakakwana kwechibereko chechivharo, kupesana kwakasimba kunopera kweminiti uye kunodzokororwa kwemaminitsi maviri maviri.
Miedzo
Munguva iyi amai vari kutarisana nechido chisingachinjiki chekudhonza nemasumbu emimba. Ichi chikamu chinogona kupedza kusvika maawa maviri, uye kuberekwa nekuberekwa kunowanzoshoma.
Kubereka
Kugadziridzwa kwemusoro kunotanga apo simba rayo guru rinosvika kumudzimai. Kakawanda kutambanudza kutenderera kwechikadzi kunosangana nekuputika kwayo. Mushure mekuonekwa kwemusoro, zvoga zvemuviri wemwana zvinoberekwa pasina chinetso. Pamusoro wehurukuro yekutanga yekutanga kuburikidza nekuberekwa kwechirwere kunotora chikamu chikuru che fetus - musoro uyo unoita kuti chibereko chemuviri chiwedzere. Munyaya iyi, mwana anogona kutanga kufema asati aberekwa. Chikamu chokupedzisira chebasa - kuberekwa kwepa placenta - inotora anenge maminitsi makumi matatu. Mushure mokuberekwa kwe fetus, rhythmic contractions yechipupuriro inopfuurira. Kushushikana kwemuviri wehutachivi hwemuropa kunopedza kubuda ropa. Kuderedza uterine masvingo kunotungamirira pakuparadzanisa kweparcenta. I-placenta uye membrane (iyo yekupedzisira) inobviswa kubva muhutachi uterine nekudhonza zvinyoronyoro pamutsara wembilical. Kuti urege kubuda ropa kwenguva refu uye utachiona mushure mokuberekwa, zvikamu zvose zve placenta zvinofanira kubviswa kubva muchibereko. Kusavapo kwemitilical arteri inowanzobatanidzwa nehutano hwemwoyo hunenge huri fetus, saka chengeta uone nhamba yemidziyo mumutsara wembilical.
Mazinga emahomoni
Maitiro eestrogens uye progesterone muhope yeropa raamai zvakanyanyisa mushure mekuberekwa kwezvakabva-iyo placenta. Mumasvondo mana kusvika mashanu, chibereko chinoderedzwa zvikuru, asi chinoramba chichikura zvakakura kupfuura zvishoma musati mimba. Iye zvino tinoziva apo zviratidzo zvokutanga zvebasa zvinotanga.