The placenta ndi chiwalo chochepa chomwe chimagwirizanitsa mayi ndi mwana. Imakhala mu chipanichi cha chiberekero, kawirikawiri pamakoma ake akumbuyo, ngakhale kuti malo ake amasiyana. Pambuyo pa kubadwa kwa mwana, tsamba la placenta pambuyo pake, patapita mphindi zingapo.
Kufunika kwa placenta n'kovuta kwambiri - kumamuthandiza mwanayo, kumamupatsa mpweya wabwino ndikuwonetsa zinthu zomwe zimagwira ntchito yofunikira. Popanda izo, n'kosatheka kulingalira mimba, chifukwa ndi chigawo chofunikira kwa mwana wakhanda. Tidzaphunziranso pang'ono za kapangidwe ndi ntchito za placenta.
Maonekedwe a placenta
The placenta ili ndi zigawo zambiri, kotero makonzedwe ake amatchedwa kapangidwe kake ka placenta. Icho chiri_chimawonedwa kuti chimayikidwa ndi wosanjikiza. Choncho, chidziwitso chake chochokera ku fetus kupita kwa mayi:
- amnion - amapanga amniotic madzi ndikuwagulitsa;
- stroma - ndi mawonekedwe ogwirizana, ali ndi ziwiya ndi maselo a microphage - Kashchenko-Gofbaur;
- cytotrophoblast - maselo omwe amapanga syncytia, secrete BAC;
- sycytiotrophoblast - snowshoeer symplast, ikuphimba cytotrophoblast;
- mbuzi - odzazidwa ndi magazi;
- trophoblast - chimakwirira lacunas, imakula m'makoma a mitsempha yowonongeka ndipo imalepheretsa kugwedeza;
- fibrinoid - mwinamwake amatchedwa Lantgans wosanjikiza;
- decidua - endometrium ndi maselo olemera a decylulus.
Zofunikira kwambiri za placenta
Mapangidwe ndi ntchito za placenta zimagwirizana. Chigawo chilichonse cha placenta chimakhala ndi udindo wopatsidwa, motero thupi limapanga ntchito zofunika izi:
- mpweya wabwino - mpweya umalowa mwana, ndipo carbon dioxide imachotsedwa mmenemo mosiyana;
- chakudya - mwanayo amatenga kupyolera mu placenta zakudya zonse zofunika
katundu. Mwamwayi, chikonga, mowa ndi mankhwala ambiri zimadutsanso chitetezo chotetezera ndikufika kwa mwanayo. Chigamulo chimaperekanso mankhwala a fetus; - Chitetezo cha umuna - chiwalo chimachepetsa maselo a mthupi a mayi, yemwe, akafika pamimba, amamuwona ngati chinthu chachilendo ndikuyesera kumuchotsa. Panthawi imodzimodziyo, placenta imanyamula ma antibodies a amayi kuti ateteze mwanayo ku matenda;
- kaphatikizidwe ka mahomoni - pulasitiki imachita mbali ya mankhwala a endocrine, kupanga mahomoni a hCG, prolactin, placental lactogen ndi zina zotero. Ndizofunika kuti pakhale mimba yoyenera komanso kukula kwa fetus.