I-oocyte liyiqanda elivuthiwe (i-ovum engavamile). Ama-oocyte athuthuka ekuvuthweni avela ngaphakathi kwe- follicle . Lezi follicles zitholakala engqimba yangaphandle yama-ovari. Phakathi nomjikelezo ngamunye wokuzala , izintambo eziningana ziqala ukuthuthukisa.
Ngokuvamile, i-oocyte eyodwa kuphela umjikelezo ngamunye uzoba yiqanda elivuthiwe futhi livulwe kusuka kuphandle yayo. Le nqubo ibizwa ngokuthi ukuvota .
Owesifazane uzalwa nawo wonke ama-oocyte ayoke abe nayo. Le nombolo inciphisa ngokwemvelo ngeminyaka . Ubudala buyanciphisa izinga kanye nokuzinza kwama-oocyte. Yingakho kunzima ukukhulelwa emva kuka-35 .
I-ovum egcwele ngokuvuthiwe ibonakala esweni lomuntu, elinganisa u-0.1 mm. Kubukhulu besilinganiso ekupheleni kwalesi sigwebo.
Izidakamizwa zokuzala ziyakwandisa inani lama-oocyte athuthukayo kanye ne- ovulating njengeqanda elivuthiwe. Lesi sizathu sengozi ephakeme yokukhulelwa okuningi uma uthatha izidakamizwa zokuzala. Kuwo wonke ama-ovum ovulated, kungenzeka ukuthi ingaba nomanyolo wesilisa wesilisa. Le-ova enomanyolo ingaba imibungu (futhi, ekugcineni, uma konke kuhamba kahle, izinsana.)
Ngesikhathi sokwelashwa , udokotela uzoqhuba ama-ultrasound ukuqapha ukukhula komthamo. Ukuvuthwa kwe-oocyte kuyenzeka futhi, kepha ukuvuthwa kwama-oocyte akubonakali ku-ultrasound. Yingakho ukukhula kwe-follicle kugcinwa futhi hhayi ukukhula kwama-oocyte.
Uma izintambo eziningi kakhulu zikhula, umjikelezo wakho wezokwelapha ungakhanselwa ukuvimbela ingozi yokukhulelwa okuningi noma i- ovarian hyperstimulation syndrome (OHSS) .
Ngesikhathi se- IVF , uma ukuqapha kwe-ultrasound kungabonakali ngokwanele ukukhula kwe-follicle-okusho ukuthi ama-oocyte akwanele akhula-umjikelezo ungakhanselwa ukuze ugweme ukuhluleka kokwelashwa.
Ukupela okuhlukile: i-oöcyte, i-ovocyte, i-ocyte.
Izigaba ze-Oocyte
U-Oogenesis yilokho i-oocyte eqhubekayo njengoba iqala ukuba yi-ovum evuthiwe.
Ungase ucabange ukuthi i-oogenesis yenzeka phakathi nenkathi yenyanga kusukela ngaleyo ndlela ovutha ngayo. Kodwa uzobe uphambene!
Nakuba kuyiqiniso ukuthi noma yiliphi iqanda elivuliwe liqedela inqubo ye-oogenesis inyanga idedelwa ku-ovary, ukuthuthukiswa kwama-oocyte kuqala ngaphambi kokuba uzalwe.
Eqinisweni, yaqala lapho usengumntwana omncane kakhulu.
Lezi yizigaba zokukhula kwama-oocyte.
I-Primordial Germ Cell
Iseli "imbewu" yawo wonke ama-oocyte yi-germ cell enkulu.
Lawa amangqamuzana e-embryonic ekugcineni ayoba ngamaseli wesilisa noma ama-oocyte.
Emlonyeni okhulayo, lawa maseli aya endaweni lapho ekugcineni kuyoba khona i-testis noma ama-ovari (owaziwa nangokuthi yi-gonads).
(Inothi elikhathazayo: Ucwaningo lithole ukuthi amanye alawa maseli e-oocyte asekuqaleni akhona kuma-ovaries omdala asebesifazane. Kungase kube nendlela esikhathini esizayo ukuthatha lawa maseli amancane bese wenza ama-oocyte amasha. Lokhu kusho ukuthi abesifazane ngeke besaba khona kunqunyelwe emaqanda abazalelwa ngawo.)
Oogonium
Uma isilwane segciwane elikhulu kakhulu sifika kule gonads, sithonywa amangqamuzana azungezile ukuba abe i- oogonium .
(Noma, ngobuningi, i- oogonia .)
I-Oogonia ingamaseli e- diploid . Lokhu kusho ukuthi banezinombolo ezimbili (di) eziphelele zama-chromosomes. Esitokisini somuntu, lokhu kungama-pair amabili noma inamba engu-46.
Lokhu kuyinto ebalulekile yokwazi ngoba i-oocyte ekugcineni iyoba nesigamu noma ama-chromosomes angu-23 kuphela. (Ngesikhathi sokufaka umanyolo, uzothola enye engama-23 kusuka esitokisini se-sperm ukuba ibe nesethi ephelele futhi.)
Phakathi nezinyanga ezinhlanu zokuqala zokuthuthukiswa kokubeletha, i-oogonium yanda ngenombolo ngokusebenzisa inqubo eyaziwa ngokuthi i- mitotic cell division .
I-Meiosis ihlukile kuma-germ cells. Kwenzeka kuphela eqanda elincane kanye namasamu omzimba.
Ngokuhlukaniswa kwamaseli okuvamile-okubizwa ngokuthi i-meiosis-amaseli okuphindaphindiwe ngokudala ama-clones ngokwabo, ngalinye linesethi egcwele yama-chromosomes.
Isibonelo, isinye isikhumba lesikhumba esihamba nge-mitosis sasizoholela emangqamuzaneni amabili esikhumba, enezici ezifanayo zofuzo.
Phakathi nokuhlukaniswa kwamaseli e-mitotic, i-oogonium ihlukaniswa ngamaseli amabili ahlukene aqukethe:
- Isilinganiso se-chromosomal kuphela: ngamanye amazwi, anama-chromosomes angu-23 kuphela. (Lawa ayaziwa ngokuthi amangqamuzana angama-haploid.)
- Amaqoqo e-chromosomal ahlukile: zonke i-oogonium ezahlukanayo zakha amaseli odade ahlukile. Lokhu kusho ukuthi akekho u-oogonium onokwabelana ngokufanayo kwe-chromosomal njengenye.
Lokhu kuhlukaniswa mitotic yingakho yonke impilo entsha inomsebenzi ohlukile wezakhi zofuzo ongafani nomunye umuntu.
Nokho, akuyona okungahleliwe ngokuphelele. Konke kusekelwe ekutheni izakhi zofuzo zokuqala zitholwe ngumbungu ovela kubaba nomama wabo.
Lawa maseli aqhubeka nokwanda aze afinyelele phezulu. Ukuphakama kwenzeka lapho ingane ekhulayo ihamba ngezinyanga ezinhlanu-eduze.
Ngalesi sikhathi, i-fetus yentombazane inama-oocyte ayizigidi ezingu-7.
Le nombolo izoqala ukwehla ngemva kwaleli phuzu. Lapho uzalwa, intombazane inamantombazane amabili kuphela ama-oocyte asele.
I-oocyte eyinhloko
Wonke ama-oocyte azohamba ngezigaba ezimbili ezihlukene ze- cellioiotic ngaphambi kokuba abe yi-ovum evuthiwe. Ukuhlukaniswa kwamaseli we-Meiotic kuholela ekukhuleni nasekuvuthweni kwe-oocyte, hhayi ama-oocyte engeziwe.
Ngasekupheleni kokuthuthukiswa kokubeletha, ama-oocyte ayeka ukuphindaphinda ngenombolo futhi aqale ukuvuthwa ngabanye.
Ngalesi sigaba, bahamba phakathi kokuqala kwesigaba se-meiotic. Lokhu kuhlukaniswa kwamaseli kuholela ekukhuleni kwama-oocyte-hhayi ama-oocyte amaningi-afana nalokho okwenzeka nge-oogonium.
Kodwa azihambisani nje nentuthuko ekukhuleni okwamanje.
I-oocyte eyinhloko igodla ekuthuthukiseni kwayo futhi igcinwe iqhwa kuze kube khona ama-hormone okuzala aqale isigaba esilandelayo.
U-Oogenesis uzoqhubeka eneminyaka yobudala.
I-oocyte yesibili
Ukukhulelwa kwentsha-iqala isigaba esilandelayo sokuvuthwa kwama-oocyte.
Akuzona zonke ama-oocyte azohamba ngalezi zigaba kamuva zokuthuthukiswa kwama-oocyte ndawonye, nakanjani. Baphindaphinda baphenduke iminyaka yokuzala yowesifazane. Inyanga ngayinye, iqoqo elisha lama-oocyte oyinhloko liqala ukuvuthwa.
Uma i-oocyte eyinhloko ishintshwe amahomoni azalisayo, iqeda isigaba I sendima ye-meiotic cell. Lokhu kwaziwa ngokuthi ukuvuthwa kwe-oocyte .
Ekupheleni kwalesi sigaba sokuqala sesigaba se-meiotic cell, iseli lihlukaniswa ngamaseli amabili ahlukene: umzimba omncane we-polar kanye ne-oocyte enkulu yesibili.
Umzimba omncane we-polar ugcina ukuwohloka.
I-oocyte yesibili iqala isigaba esilandelayo sokuvuthwa.
Ootid
I-oocyte manje iqala isigaba sesibili sesigaba se-meiotic cell.
Ekugcineni, i-oocyte yesibili izophinde ihlukaniswe ngamaseli amabili ahlukene: elinye iseli lomzimba elincane le-cell elincane elivuthiwe.
Le seli elikhulile elivuthiwe liyaziwa njenge-ootid.
Njengangaphambili, i-cell body encane ye-polar izogcina ihlahloke.
Ukuvuthwa kwenzeka uma i-oocyte ifinyelele esigabeni se-ootid yentuthuko.
I-Ovum
Ngesikhathi sokuvuthwa, i-ootid ikhishwa ku-follicle.
Amaqanda amaqanda omuntu akakwazi ukuhambisa eyedwa. Esikhundleni salokho, izilinganiso ezinjengamunwe zidweba i-oocyte kuya emgqonyeni we-fallopian .
Uma usengaphakathi kwe-tube fallopian, izinwele ezincane-ezinjengezicabha ezibizwa ngokuthi i-cilia ziyaqhubeka zidweba i-ootid.
Emgodini we-fallopian, uma ukukhulelwa kwenzeka, i-ootid ihlwanyelwa umuthi wesilisa.
Uma lokhu kokukhulelwa kwenzeka, i-ootid ihamba ngesigaba sayo sokugcina sokuvuthwa futhi iba i-ovum, isisindo seqanda lomuntu elivuthiwe ngokugcwele.
Kulungile; i-oocyte ayikwazi ukuqedela ukuthuthukiswa kwayo okugcwele ngaphandle kokukhulelwa.
Kusukela ku-Oocyte kuya ku-Ovum kuya ku-Zygote
Ngesikhathi sokukhulelwa, i-ovum ne-sperm cell cell ihlanganisa, ngayinye iqukethe ama-chromosomes angu-23 ngayinye.
Kunalokho ngokushesha (kodwa hhayi ngesikhathi esifanele sokukhulelwa), lawa ma-chromosomes ahlangana ndawonye, ekwakheni iseli elisha ngeqoqo eligcwele lama-chromosomes.
Leli seli elisha libizwa nge -zygote .
I-zygote izokhula ibe umbungu futhi, cishe izinyanga eziyisishiyagalolunye kamuva, umntwana osanda kuzalwa.
Imithombo:
U-Alberts B, uJohnson A, Lewis J, et al. Biological Molecular of the Cell. Edition 4. ENew York: i-Garland Science; 2002. http://www.ncbi.nlm.nih.gov/books/NBK26842/
Grudzinskas, uJurgis Gedimina; Yovich, JL Gametes - I-oocyte . Ukubuyekezwa kwe-Cambridge ekuzalweni komuntu. Inguqulo engu-1, ka-1995. Amakhasi 9 kuya ku-10.
White YA1, Woods DC, Takai Y, Ishihara O, Seki H, Tilly JL. "Ukwakhiwa kwama-oocyte ngama-germ cells asebenzayo ahlanzekile avela kuma-ovari womama wesifazane wokuzala." UNathan Med. 2012 Feb 26; 18 (3): 413-21. i-doi: 10.1038 / nm.2669. http://www.nature.com/nm/journal/v18/n3/full/nm.2669.html