Ngaphambi kokubeletha
Yisiphi isibonakaliso sokuqala komsebenzi esingaziwa, kodwa kunezici eziningi ezithinta ukuqala kwezehlakalo eziholela ekuzalweni kwe-fetus. Izinga le progesterone, eligcwala yi-placenta emgodleni wegazi lomama, lifinyelela phezulu ngaphambi kokubeletha. I-progesterone yi-hormone enomthwalo wokugcina ukukhulelwa. Inomphumela wokuphumula emzimbeni oshelelekayo wesibeletho.
Izibonakaliso ze-hormonal
Ngasekupheleni kokukhulelwa, isikhala se-intrauterine siyancipha kancane kancane, futhi ukulethwa kwe-oksijini emfubeni kuyanda kancane (i-placenta ngeke isakwazi ukuhlangabezana nezidingo ze-fetus ekhula ngokushesha). Lokhu kuholela ekwandiseni ukwedlula i-horrenone ye-adrenocorticotropic (ACTH) ku-lobe yangaphakathi ye-fetal pituitary gland. I-ACTH igqugquzela i-cortex e-adrenal, eyimfihlo ye-glucocorticoids, eyenza umphumela wokulimaza ekusithekeni kwe-progesterone ku-placenta. Ngesikhathi esifanayo, izinga le-estrogen elikhiqizwa yi-placenta liba likhulu, elihambisana nokubukeka kwamaseli omzimba we-womb receptors ye-oxytocin (lesi sibeletho siba nesifo esibucayi kakhulu ku-oxytocin).
Iyaqinisa
Kancane kancane, umphumela wokuvimbela we-progesterone kumaseli ashelelekile we-muscle kukhishwa umphumela okhulayo wama-estrogens. Ukukhulelwa kuqala ukuzwa ukuhlukana kokuqala okubuthakathaka kozalo olubizwa ngokuthi yi-Braxton-Hicks. Basiza ekunciphiseni umlomo wesibeletho ekulungiseleleni ukuzalwa kwengane futhi ngokuvamile bephutha ngomfazi njengesiqalo sokubeletha. Ekupheleni kokukhulelwa, i-receptors yomlomo wesibeletho ivuselela i-hypothalamus yomama (indawo yobuchopho), evuselela i-pituitary ukukhulula i-hormone oxytocin. Le hormone iphinda ikhiqize amanye amangqamuzana e-fetal. Uma izinga le-oxytocin landa, i-placenta iqala ukwenza izakhi ze-prostaglandins, ezibandakanya nezingqinamba ze-uterine.
Ukuqiniswa kwezingqinamba
Njengoba lesi sibeletho sithinta kakhulu i-oxytocin, ukwehlukanisa kancane kancane kwanda futhi kwanda. Ukuphika okuqinile njalo kubonisa ukuqala komsebenzi. Njengoba izingqinamba ziqinisa, indlela enhle yokwenza umbiko inikeza ukwanda kokuhlanganiswa kwe-oxytocin, okuholela ekubhekaneni nakwezinye izingqinamba ezinkulu ze-uterine. Le ndlela iphela ukusebenza emva kokubeletha, lapho umlomo wesibeletho unqanyuliwe. Inqubo yokubeletha ihlukaniswe ngezigaba ezintathu: ukuvulwa komlomo wesibeletho, ukuxoshwa kwe-fetus nokuzalwa kwe-placenta.
Ukudalula
Ekhanda lomntwana lingadlula emgodini wokubeletha, umlomo wesibeletho kanye nesiswini kufanele sithele cishe ngo-10 cm ububanzi. Ukubeletha kuqala ngokuchotshozwa okungekho emthethweni engxenyeni engenhla kwesibeletho. Lezi zinciphiso zokuqala zithatha imizuzwana engu-10-30 ngezikhathi ezinemizuzu engu-15-30. Njengoba lo msebenzi uqhubeka, iziphambano ziba njalo futhi zikhudlwana futhi kancane kancane zihambela engxenyeni engezansi yesibeletho. Ikhanda lomshini we-fetus ngokumelene nesisu somlomo wesibeletho kukho konke ukuphikisana, okuyinto eyenza ukuvula nokutholwa kancane kancane. Ngesikhathi esithile, i-membrane e-amniotic evikela isisu ngesikhathi sokukhulelwa, nokuphuma kwe-amniotic fluid, yehla.
Ukufaka
Isikhathi sokudalula yisigaba eside kunazo zonke sokusebenza, esihlala emahoreni angu-8 kuya kwangu-24. Kulesi sigaba, i-fetus iqala uhambo lwayo emgodini ovamile, ngesikhathi esifanayo. Ekugcineni, ikhanda lifakwe esikhwameni esincane somama. Isigaba sesibili somsebenzi siqala ngokudalulwa ngokugcwele komlomo wesibeletho kuze kufike ngesikhathi sokuzalwa kwangempela kwengane. Ngokudalulwa ngokugcwele komlomo wesibeletho, ukuphikisana okunamandla kuqhubeka cishe ngomzuzu futhi kuphindwe njalo ngemizuzu 2-3.
Imizamo
Phakathi nalesi sikhathi umama uhlangabezana nesifiso esingenakuphikiswa sokumelana nemisipha yomzimba. Lesi sigaba singaphelela amahora amabili, ngokubeletha ngokuphindaphindiwe kuvame kakhulu.
Ukubeletha
Ukukhishwa kwekhanda kuqala uma ivolumu yayo enkulu kakhulu ifinyelela emzimbeni. Ngokuvamile ukwelula ngokweqile kwesisindo kuhambisana nokuphuka kwayo. Emva kokuvela kwekhanda, wonke umzimba womntwana uzalwa ngaphandle kobunzima. Esikhathini esethula ikhanda lomuntu wokuqala ngokusebenzisa umthamo wokubeletha udlula ingxenye enkulu kunazo zonke ze-fetus - ikhanda elikhulisa umlomo wesibeletho. Kulesi simo, ingane ingaqala ukuphefumula ngaphambi kokuzalwa okuphelele. Isigaba sokugcina sokusebenza - ukuzalwa kwe-placenta - kuthatha imizuzu engaba ngu-30. Ngemuva kokuzalwa kwe-fetus, iziphazamiso zomzimba zesisu ziqhubeka. Ukucindezelwa kwemithambo yegazi ye-uterine kunciphisa ukuphuma kwegazi. Ukunciphisa izindonga ze-uterine kuholela ekuhlukaneni kwe-placenta. I-placenta ne-membrane (okugcineni) zisusiwe emgodini we-uterine ngokudonsa ngobumnene emthonjeni womzimba. Ukuze ugweme ukuphuza isikhathi eside nokutheleleka ngemva kokubeletha, zonke izingcezu ze-placenta kumele zisuswe esibelethweni. Ukungabi khona kwe-artery embilical ngokuvamile kuhlotshaniswa ne-anomalies ye-fetus ye-cardiovascular, ngakho-ke hlola njalo inani lemikhumbi emgqeni we-umbilical.
Amazinga amahomoni
Amazinga we-estrogens kanye ne-progesterone egazini legazi lomama ngokukhawuleza emva kokuzalwa komthombo wabo - i-placenta. Kungakapheli amasonto amane kuya kwahlanu, lesi sibeletho sinciphile kakhulu, kodwa sihlala sisayizi enkulu kakhulu kunaphambi kokukhulelwa. Manje siyazi lapho kuqala izimpawu zokuqala zomsebenzi.