I-placenta iyisitho sesikhashana esixhuma umama nengane. Itholakala enkundleni yamangcwaba yesibeletho, ngokuvamile esendongeni layo elingemuva, nakuba isikhundla sayo singashintsha. Ngemva kokuzalwa kwengane, i-placenta ihamba ngemuva kwayo, emva kwemizuzu embalwa.
Ukubaluleka kwe-placenta kunzima ukugcizelela - kuyondla umntwana, kuyayithumela oksijini kuyo futhi kubonise imikhiqizo yomsebenzi obalulekile. Ngaphandle kwalo, akunakwenzeka ukucabanga ukukhulelwa, ngoba kuyisici esibalulekile kumntwana okhulayo. Sizofunda okwengeziwe mayelana nokuthi yiziphi izakhiwo nemisebenzi ye-placenta?
Isakhiwo se-placenta
I-placenta iqukethe izingqimba eziningi, ngakho-ke isakhiwo sayo kuthiwa yisakhiwo sakhe se-placenta. Lokho-kucatshangwa ukuthi ungqimba ngendlalelo. Ngakho-ke, i-histology ye-placental kusukela embusus kuya kumama:
- i-amnion - ihlanganisa ama- amniotic fluid futhi iwazisa;
- i-stroma - iyisisindo esihlangene, iqukethe izitsha namaseli we-microphage-iKashchenko-Gofbaur;
- ama-cytotrophoblast - amangqamuzana akha i-syncytia, i-secrete BAC;
- i-syncytiotrophoblast - i-snowshoeer symplast, ihlanganisa i-cytotrophoblast;
- amaqhubi - agcwele igazi;
- i-trophoblast - ihlanganisa lacunas, ikhula ibe ezindongeni zemithambo ye-spiral futhi ivimbela ukuphika kwayo;
- i-fibrinoid - okunye okubizwa nge-Lantgans ungqimba;
- i-decidua - i-endometrium enezakhi ze-decylulus ezicebile ze-glycogen.
Imisebenzi eyisisekelo ye-placenta
Isakhiwo nemisebenzi ye-placenta zihlobene. Ingqimba ngayinye ye-placenta idlala indima eyabelwe yona, ngenxa yalokho, umzimba wenza imisebenzi ebalulekile kangaka:
- ukushintshaniswa kwegesi - i-oksijini ingena emntwaneni, futhi i-carbon dioxide isuswa kuwo ngokuphambene;
- ukudla - i-fetus ithola i-placenta zonke izakhi ezidingekayo
izinto. Ngeshwa, i-nicotine, utshwala nemithi eminingi nayo idlula emkhakheni wokuvikela futhi ufike emntwaneni. I-placenta isetshenziselwa ukuguqula imikhiqizo ye-fetus; - Ukuvikelwa komzimba - i-placenta iphuza amangqamuzana omzimba omama, owathi, lapho efika emntwaneni, angambheka njengento yangaphandle futhi azame ukumbulala. Ngesikhathi esifanayo, i-placenta iphethe amantombazane omzimba ukuvikela ingane yakho ekufweni;
- i-synthesis of hormones - i-placenta idlala indima ye-endocrine gland, yokwenza ama-hormone we-hCG, i-prolactin, i-lactogen ephahleni nezinye izinto. Ziyadingeka ekwenzeni okujwayelekile kokukhulelwa nokuthuthukiswa komntwana.