Chigamulo ndi chiwalo chofunikira kwambiri chomwe chimayambitsa kukula bwino kwa mwana m'mimba mwa mayi. Pamene chilondacho chimawoneka bwino, mwanayo amapeza nyumba yake yoyamba (osati popanda chifukwa chake malo otchedwa a placenta amatchedwa malo a mwana ), zomwe zimathandiza kuti zonse zitheke pa kukula ndi chitukuko, ndipo pambali pake zimateteza munthu wake wamng'ono ku poizoni ndi zinthu zina zomwe sizothandiza, ili mu thupi la mayi. Kuwonjezera pa kupereka mwana wamphongo ndi zinthu zothandiza, placenta imayambitsa mpweya wabwino komanso kuchotsedwa kwa zinyalala.
Mapangidwe a placenta pa nthawi ya mimba
N'zovuta kudziwa nthawi yomwe pulasitiki imayambira, chifukwa gawo loyamba likhoza kutchulidwa kale mpaka tsiku lachisanu ndi chiwiri pambuyo pathu. Pakadali pano, kamwana kameneka kamadula mu uterine mucosa, kukakhazikika mumadzi otchedwa lacuna, omwe amadzazidwa ndi magazi a amayi. Pa nthawiyi, chorion ikukula - envelopu yakunja ya mwana wosabadwayo, yomwe imatha kutchedwa kuti precursor of the placenta.
Mphindi 15-16 ya mimba - ino ndi nthawi yopanga pulasitiki. Pakadutsa sabata la 20, pamene limba likonzekera ntchito yodziimira, mapangidwe a placenta amatha.
Pa nthawi yomwe ali ndi mimba popanda vuto lililonse komanso kupwetekedwa, placenta imapangidwa kumbuyo kapena kumbuyo kwa chiberekero. Nthawi yoti mapangidwe a pulasitiki apangidwe amachokera kumbali ya thupi, koma monga lamulo, ndi sabata lachisanu ndi chitatu la mimba limba limayamba kukula. Nthawi yomweyo asanabadwe, placenta ili ndi masentimita 2 mpaka 4, ndipo m'mimba mwake imadutsa masentimita 18.
Placenta atabadwa
Mosasamala masabata angati pulasitiki imapangidwa, limba limagwira magawo 4 akukula pa nthawi ya mimba. Chodabwitsa n'chakuti, asanabadwe, placenta ili mu ukalamba - miyeso yake imachepa pang'ono, ndipo mchere umayang'ana pamwamba. Uwu ndiwo kukula kwachinayi kwa pulasitiki .
Pambuyo kubadwa, placenta imasiyanitsidwa pamakoma a chiberekero mosapitirira mkati mwa mphindi 15-20. Nthawi zina, zingatenge nthawi yaitali - mphindi 50. Dokotala ayenera kufufuza mosamala kukhulupirika kwa placenta kuti atsimikizire kuti palibe zidutswa zomwe zatsalira pachiberekero zomwe zingayambitse kutupa. Kenaka placenta imatumizidwa ku maphunziro a morphological, malinga ndi zotsatira zomwe zingatheke kuyesa nthawi yomwe ali ndi mimba komanso zifukwa zomwe zingatheke.