Wani oocyte ne mai kwai wanda bai kasance ba. Oocytes ci gaba zuwa balaga daga cikin wani follicle . Wadannan ƙwayoyin suna samuwa a cikin waje na Layer ovaries. A kowane lokacin sake haifuwa , ƙwayoyi masu yawa zasu fara girma.
Yawancin lokaci, kawai oocyte kowane sake zagayowar zai zama tsumburai tsutsa kuma za a ovulated daga follicle. Wannan tsari ana sani da kwayar halitta .
An haifi mace tare da dukan malacytes da ta samu. Wannan lambar yana raguwa da tazarar shekaru . Shekaru kuma yana rage inganci da kwanciyar hankali na kwayoyin owacytes. Wannan shi ya sa ya fi wuya a yi ciki bayan 35 .
Kwancen da aka bazu a cikin ido yana iya gani a ido na mutum, kimanin 0.1 mm. Yana da kusan girman lokacin a karshen wannan jumla.
Magunguna na haihuwa na iya kara yawan adadi na masu tasowa masu tasowa da kuma yin amfani da su a matsayin ƙirar balagagge. Wannan shi ne dalilin hadarin haɗari na ciki lokacin daukar nauyin ƙwayoyi. Ga kowane ovum da aka yiwa, akwai yiwuwar zai iya samuwa ta hanyar kwayar halitta. Wadannan takaddun sunaye zasu iya zama jarabawa (kuma, idan duka yana da kyau, jariran.)
Yayinda likita ke haihuwa , likita za ta gudanar da kayan aiki don saka idanu akan ci gaban kwayoyi. A oocyte maturation ma faruwa, amma oocyte maturation ba bayyane a kan duban dan tayi. Wannan shi ne dalilin da yasa ake ci gaba da bunkasa kwayar halitta kuma ba girma.
Idan yawancin ƙwayoyin suna girma, za a iya soke hanyar sake zagayowar ku don hana haɗarin ɗaukar ciki ko ciwon hauka na hyperstimulation (OHSS) .
A lokacin IVF , idan saka idanu na duban dan tayi bai nuna adadi mai girma ba - wanda ke nufin bai isa adadin kacytes suna maturing ba - za a iya soke wannan sake zagayowar don kauce wa rashin nasarar jiyya.
Karin bayani : oöcyte, ovocyte, ocyte.
Matsayi na Oocyte
Oogenesis shine abin da kwayoyin kwayoyin halitta ke wucewa yayin da yake tasowa a cikin jariri.
Kuna iya ɗauka cewar oogenesis yana faruwa a cikin wata na wata tun da cewa sau nawa zaka yi koyi. Amma za ku zama ba daidai ba!
Yayinda yake da gaskiya cewa duk wani kwaya wanda aka yi amfani da shi ya cika tsarin tafiyar da samin oganisu a watan da aka sake shi daga kogin, shirin ciyayi ya fara tun kafin a haife ku.
A gaskiya ma, ya fara lokacin da kake da yarinya.
Wadannan su ne matakai na girma na oocyte.
Primordial Germ Cell
Tsararren "nau'in" kowane nau'in kwayar kwayar halitta ita ce maɓallin kwayar halitta.
Wadannan kwayoyin halitta ne wanda zasu zama magungunan jini ko ƙwayoyin tucyte.
A cikin amfrayo masu tasowa, waɗannan kwayoyin sun motsa cikin yanki wanda zai zama ko dai gwajin ko ovaries (wanda aka fi sani da gonada).
(Bayanan martaba mai ban sha'awa: Binciken ya gano cewa wasu daga cikin wadannan kwayoyin halitta na farko sun samo a cikin ovaries mata masu girma. Akwai yiwuwar a nan gaba ta dauki wadannan kwayoyin sutura kuma su haifar da sababbin magunguna. Wannan yana nufin cewa mata ba zasu kasance ba iyakance ga qwai da aka haife su tare da.)
Oogonium
Da zarar kwayar cutar kwayar halitta ta zo a cikin gonar, kwayoyin dake kewaye sunyi rinjayar su zama oogonium .
(Ko, a cikin jam'i, oogonia .)
Oogonia ne kwayoyin diploid . Wannan yana nufin suna da nau'o'i guda biyu (na) na chromosomes. A cikin tantanin mutum, wannan nau'i nau'i nau'i nau'i 23 ne ko 46 na duka.
Wannan abu ne mai mahimmanci ya sani saboda oocyte zai sami rabin ko 23 chromosomes. (A lokacin hadi, zai sami sauran 23 daga tantanin halitta don tantance saiti.)
A cikin watanni biyar na farko na ci gaba na shan ciki, hawan oogonium ya karu da lambar ta hanyar tsari da aka sani da rabo daga sassan mota .
Meiosis na da ƙwayoyin kwayoyin halitta. Sai kawai yana faruwa a cikin kwai kwai da kwayoyin jini.
A cikin sassan jiki na musamman-wanda aka sani da kwayoyin halittu-nau'in halitta ta hanyar ƙirƙirar clones daga kansu, kowannensu yana da cikakkiyar tsari na chromosomes.
Alal misali, ƙwayar fata daya ta hanyar mitosis zai haifar da ƙwayar fata guda biyu, tare da irin wadannan lambobin kwayoyin.
A lokacin rabuwa na mitotic cell, oogonium ya rabu biyu cikin kwayoyin halitta wanda ya ƙunshi:
- Kashi rabi na chromosomal aka saita: a wasu kalmomi, suna da kawai 23 chromosomes. (Wadannan suna da sanannun salloid.)
- Kwancen chromosomal na musamman ya kafa: kowane nau'i mai yawa wanda ya rabu ya haifar da ƙwayoyin 'yan uwa ta musamman. Wannan yana nufin cewa babu wanda ya yi amfani da akosoni a cikin kayan shafa guda daya.
Wannan rukuni na mota shi ne dalilin da yasa kowane sabon rayuwa yana da kwarewar kwayoyin halitta wanda ba kamar kowa ba.
Duk da haka, ba gaba ɗaya bazuwar. Dukkansu sun dogara ne akan ainihin kwayoyin halitta da jaririn ta samu daga mahaifinta da uwa.
Wadannan kwayoyin sun ci gaba da ninka har sai sun isa hawan su. Hakan yana faruwa a lokacin da tayin tayi yana kusa da watanni biyar.
A wannan lokaci, yarinyar yarinyar yana da miliyoyin 7.
Wannan lambar zai fara karuwa bayan wannan batu. A lokacin haihuwar, yarinya yarinya kawai ya bar miki biyu kawai.
Primary Oocyte
Kowane oganci zai shiga cikin rassa biyu na rarrabe a tsakaninta kafin ya zama jariri. Yankin Meiotic yana haifar da girma da balagagge na oocyte, kuma ba karin malacytes ba.
Zuwa ƙarshen ci gaban da ake ciki, odacy na da ninkawa a yawan kuma suna fara girma.
A wannan mataki, suna tafiya ta hanyar rarraba maiotic na farko. Wannan rukuni na sel yana haifar da ciyayi-ba karin ocycy-kamar abin da ya faru da oogonium.
Amma ba su da sauri ta hanyar ci gaba zuwa balaga yanzu.
Harkokin farko na odacytes sun daskare a cikin ci gaba su kuma kasance daskarewa har sai halayen haifa na haifar da mataki na gaba.
Oogenesis zai cigaba da tsufa.
Secondary Oocyte
Jigon bugawa-farawa na gaba na farfajiyar mamacyte.
Ba dukan malacytes zasu shiga cikin wadannan matakai na gaba na ciyayi ba, ba shakka. Sun fi yawa ko žasa suna juyo bayan shekaru masu haihuwa. Kowace wata, sabon saiti na magunguna na farko zai fara girma.
Da zarar jaraban kwayar cutar ta fara amfani da kwayoyin halitta, sai ta kammala Stage I na rarraba maiotic cell. Wannan shi ne ana sani da oocyte maturation .
A karshen wannan mataki na farko na sashin kwayoyin halitta, kwayar halitta ta rabu biyu zuwa kwayoyin halitta guda biyu: wani karamin karamin ƙwayar pola da kuma babban macyte na biyu.
Ƙananan ƙwayar polar ƙarshe ya ɓata.
Da na biyu oocyte fara mataki na gaba na maturation.
Ootid
Aiki na yanzu yana farawa na karo na biyu na rarraba maiotic cell.
A ƙarshe, macyte na biyu za ta sake raba zuwa kwayoyin halitta guda biyu: wani ƙwayar jikin kwayar halitta da ƙwayar girma.
Wannan tsofaffin kwayar halitta tana da masaniya kamar ootid.
Kamar yadda a baya, ƙananan ƙwayoyin jikin kwakwalwa za su ɓace.
Ovulation yana faruwa a lokacin da oocyte ya kai mataki na ci gaba.
Ovum
A lokacin yaduwa, an fitar da wani ootid daga jakar.
Kwayoyin jikin mutum ba zasu iya motsawa akan kansu ba. Maimakon haka, yunkurin yatsa ya jawo hankalin gadon zuwa ga cikin kwandon fallopin .
Da zarar a cikin motar fallopian, ƙananan hanyoyi masu launin gashi da aka sani da cilia suna ci gaba da zub da ootid tare.
A cikin tarkon fallopian, idan ciki ya faru, ana amfani da ootid ta hanyar kwayar halitta.
Da zarar wannan hadisin ya faru, ootid yana wucewa ta karshe na maturation kuma ya zama ovum, jikin mutum mai cikakke.
Wannan gaskiya ne; Maganin oocyte ba zai iya kammala cikakken ci gaban ba tare da hadi ba.
Daga Oocyte zuwa Ovum zuwa Zygote
A lokacin hadi, kwayoyin ovum da kwayar halitta sun hada, kowannensu ya ƙunshi 23 chromosomes kowace.
Maimakon sauri (amma ba a daidai lokacin haɗuwa ba), waɗannan chromosomes sun hada tare, suna samar da sabon kwayar halitta tare da cikakken tsari na chromosomes.
Wannan sabon tantanin halitta ana kiransa zygote .
Zygote zai ci gaba da zama cikin amfrayo, kuma kimanin watanni tara bayan haka, jariri.
Sources:
Alberts B, Johnson A, Lewis J, et al. Biology Biology na Cell. 4th edition. New York: Garland Science; 2002. http://www.ncbi.nlm.nih.gov/books/NBK26842/
Grudzinskas, Jurgis Gedimina; Yovich, JL Gametes - The Oocyte . Masana binciken Cambridge a cikin Rawanin ɗan adam. 1 edition, 1995. Shafukan 9 zuwa 10.
White YA1, Woods DC, Takai Y, Ishihara O, Seki H, Tilly JL. "Oocyte samuwar ta hanyar m mitotically aiki germ kwayoyin tsarkake daga ovaries na haihuwa haifuwa mata." Nat Med. 2012 Feb 26, 18 (3): 413-21. Doi: 10.1038 / nm.2669. http://www.nature.com/nm/journal/v18/n3/full/nm.2669.html