I-placenta yilungu lexeshana elidibanisa umama kunye nomntwana. Itholakala kwi-membrane ye-mucous ye-uterus, ngokuqhelekileyo kwindonga yayo yangasemva, nangona indawo yayo ingahluka. Emva kokuzalwa komntwana, i-placenta ishiya emva kwayo, emva kwemizuzu embalwa.
Ukubaluleka kwe-placenta kunzima ukugqithisa - kuyondla umntwana, iguqula i-oksijini kuyo kwaye ibonise iimveliso zentshukumo ebalulekileyo. Ngaphandle kwayo, akunakwenzeka ukucinga ukukhulelwa, kuba liyinxalenye ebalulekileyo kumntwana okhulayo. Siza kufunda okungakumbi malunga nokuba yintoni isakhiwo nemisebenzi yepentecenta?
Ulwakhiwo lweplacenta
I-placenta inemiqolo emininzi, ngoko ke isakhiwo sayo sithathwa njengesakhiwo sakhe se-eptological of placenta. Oko kuthethwa ngathi kuluhlu lokubeka. Ngoko, i-histology ye-placental ukusuka embuseni kuya kumama:
- i-amnion - idibanisa i- amniotic fluid ize ikhangise;
- i-stroma - iyisisombululo esinoxhumo, iqulethe iimpahla kunye neeseli ze-microphage-iKashchenko-Gofbaur;
- i-cytotrophoblast - iiseli ezenza i-syncytia, i-secrete BAC;
- i-syncytiotrophoblast - i-snowshoeer symplast, ihlanganisa i-cytotrophoblast;
- i-lacunae- egcwele igazi;
- i-trophoblast - ihlanganisa i-lacunas, ikhula ibe yiindonga zeemibhobho yokuvutha kwaye ivimbela ukusikwa kwayo;
- i-fibrinoid - ngenye indlela ibizwa ngokuba yiLantgans;
- i-decidua - endometrium eneesithambiso esinezityebi ze-decylulus.
Imisebenzi ebalulekileyo ye-placenta
Isakhiwo kunye nemisebenzi yeplacenta iyahambelana. Uluhlu ngalunye lweplacenta ludlala indima ebelwe yona, ngenxa yoko, umzimba wenza imisebenzi ebalulekileyo:
- ukutshintshwa kwegesi - i-oksijini ingena kumntwana, kunye necarbon dioxide isuswe kuyo kwindlela eyahlukileyo;
- ukutya - umntwana ufumana i-placenta zonke izondlo eziyimfuneko
izinto. Ngelishwa, i-nicotine, utywala kunye nemichiza eninzi nayo idlula kwinqanaba lokukhusela kwaye lifike kumntwana. I-placenta isetyenziselwa ukuguqula imveliso yomntwana; - Ukukhuselwa kwe-immunological - i-placenta ilibazisa iiseli ze-immune zomama, owathi, xa efika emntwaneni, wayeya kumjonga njengento yangaphandle kwaye azame ukumlahla. Ngelo xesha, i-placenta ithwala izikhuselo zomama ezikhuselekileyo ukuze zikhusele umntwana kwiintsholongwane;
- ukuhlanganiswa kwamahomoni - i-placenta idlala indima ye-endocrine gland, ihlanganiswe i-hormone ye-hCG, i-prolactin, i-lactogen ye-placental njalo njalo. Ziyimfuneko kwikhosi eqhelekileyo yokukhulelwa kunye nophuhliso lomntwana.