Gastrulation - ke ... Ukwakheka umbungu multi-egqinsiwe

Blastula ebhaliwe, ebizwa nangokuthi i-bubble germinal, kuwumphumela yokugcina yokuwela amaqanda. Isinyathelo esilandelayo emva kwakhe, ithatha isikhundla Lesisemkhatsini phakathi ukuchotshozwa futhi organogenesis, embryogenesis kuyinto gastrulation. nencazelo yalo eyisisekelo ukwakheka izingqimba lwegciwane ezintathu: endoderm, yi-ectoderm ne-mesoderm. Ngamanye amazwi, it gastrulation liqala ngala morphogenesis embryonic ne kwamangqamuzana i umzimba.

Sencazelo "gastrulation"

Ngisho emuva ngo-1901 gastrulation iye yachazwa ngokuthi indlela lapho umbungu ngaphakathi ukuwa mesoderm, endoderm futhi yi-ectoderm amaseli. Lenchazelo kusho ukuba khona ekhethekile blastula organoobrazuyuschih izikhala. Ukuyiqonda injongo yangempela yokunikezwa kungcono incazelo lilula, kulula ukuba uthuthele ebudisi wesimanje kwethemu. Gastrulation - uchungechunge ukunyakaza morphogenetic eziletha ukuhamba iziqalo lendwangu endaweni eliyifa lawo ngokuhambisana "uhlelo" kwenhlangano zomzimba. Inqubo izinguquko eziyinkimbinkimbi ahambisana nokukhula nasekuvezeni izithombo zaso ezintsha, ukunyakaza ohlangothini kanye kwamangqamuzana amaseli.

Uma ucabangela gastrulation ngomqondo ajwayelekile, ke kungaba azimisele njengenhlangano sinyathelo Lesisemkhatsini, okuqondene inqubo olulodwa ashukumisayo, phakathi kwesikhathi lapho izigaba rearrangement blastula, okuyinto kakhulu kusiza inqubo kwathatha organogenesis.

Ukuhambisa amaseli

Uma ukunikeza incazelo jikelele inqubo akhuluma ngayo, singasho ukuthi gastrulation - ke embolism futhi epiboly. Womabili la magama abonisa ukunyakaza morphogenetic amaseli, okuyinto eyenzeka ngokuphelele kuzo zonke izigaba ukuthuthukiswa ontogenetic umzimba. Nokho, ngokuvamile kakhulu liphinyiselwe uma gastrulation. Epiboly ngokuthi inqubo ihambahamba phezu kobuso kuyi-nucleus yengqamuzana, futhi embolism - ukunyakaza kwabo ngaphakathi kwalo.

Ngo Embryology ukuhlukanisa lezi zinhlobo ezilandelayo eyinhloko gastrulation noma cell ukunyakaza: intussusception, kwamanye amazwe, involution, delamination futhi epiboly. Ukuze uthole ukwaziswa okwengeziwe ngabo - kamuva esihlokweni.

Ukuhambisa iseli izingqimba

Bamba iqhaza inqubo gastrulation abakwazi kuphela ukwehlukanisa (uthuthe ngokukhululekile) amaseli, kodwa futhi wonke iseli amashidi. Isiqondiso uzimisele futhi njalo ekuxhumaneni ezikude. Amabutho kuqala wavula P. Weiss ku 20s kwekhulu elidlule, futhi icala labo lubonakala embryogenesis, kwesibili - a morphogenesis ezingavamile futhi ekhethekile, e evamile zenzeka ne okungenzeka ongaphakeme.

Lapho gastrulation iseli kwehlukana kwenzeka. Njengoba sekushiwo ngenhla, ukunyakaza kuqala futhi uquqaba iseli ngenxa ukwakheka ezimbili ungqimba embryonic ngokuthi gastrula. Iba ngokucacile endoderm ebonakalayo futhi yi-ectoderm. Zonke izinto eziphilayo ezinamangqamuzana amaningi (ngaphandle coelenterates kuphela) gastrulation parallel noma ngokushesha ngemva wawubumba is germinal leaf lesithathu ngokuthi mesoderm. Kuyinto iqoqo amaseli elise phakathi endoderm futhi yi-ectoderm. Ngenxa yalokho, i-embryo iba emithathu ungqimba.

Izindlela gastrulation kuyinto encike ngqo kwi uhlobo blastula.

gastrula invaginated

igama indlela liyazikhulumela. Intussusception - single-ungqimba odongeni invagination we blastula (balstodermy) ngaphakathi blastocoel. I bakudala kakhulu futhi isibonelo osobala kakhulu ibhola zenjoloba. Ngokuchofoza impahla ke icindezelwa ngaphakathi. Invagination lungenzeka odongeni ezikude noma alenze abangelutho. Imiphumela iba yinhlanganisela yokukhandleka tingucuko blastula futhi gastrula etholwe njengendlela ezimbili isikhwama ungqimba archenteron. nodonga lwawo bangaphakathi endoderm eyinhloko futhi yangaphandle - yi-ectoderm eyinhloko. I kwaphumela lapho archenteron (amathumbu okuyinhloko) baxhumana ngaphandle esebenzisa izimbobo, ngokuthi blastopore. Igama lakhe lesibili - emlonyeni eyinhloko. Ukuthuthukiswa Its okwengeziwe kuncike hlobo umzimba. Ezilwaneni eziningi blastopore ekugcineni ibe umlomo esichazayo. Kule ndaba, babiza protostomes (molluscs, izimpethu, eyisinambuzane). Ngezinye deuterostome blastopore iguqulwe ukuze imbobo Neuro-emathunjini ngokufanele engxenyeni ezingemuva umbungu (e chordates) noma ingquza.

wezifiki gastrula

Ukuthuthela Kwelinye Izwe gastrulation - indlela ukwakha ungqimba double umbungu, isici iningi coelenterates. kwakhiwa Gastrula is by esebenzayo ingxenye nimkhiphele blastocoel kwamaseli blastula. Lokhu wezifiki kuyinto unipolar ngokwemvelo. Amaseli ukuhambisa kuphela isigxobo vegetal. Kamuva bakha endoderm, t. E. Ungqimba kwangaphakathi. Yileyo ndlela gastrulation lwenzeka ngesikhathi hydroids jellyfish.

amaseli blastoderm phakathi blastocoel akwazi ukungena noma iyiphi indawo eyodwa, kodwa kuwo wonke umbungu ebusweni. Lokhu wezifiki wabizwa ngokuthi multipolar, kodwa wakuthola ngempela ezingavamile.

coelenterates abaningi, okuyinto engavamile kwamanye amazwe ngendlela gastrulation kwenzeka asebenzayo kakhulu "kokuxoshwa" amaseli blastula futhi gastrula, kwakheka ngenxa yalokho, ilahlekelwa blastocoel. Kulokhu, lo sici for indlela odlule invaginated blastopore ku-intanethi.

Delaminatsionnaya gastrula

Lokhu zezinyoni ezingavamile yaqale echazwe gastrula Mechnikovym I. I., futhi kuba ejwayelekile ye coelenterates. Ukuhambisana gastrulation izinqubo kukhona eyinqaba kakhulu, kodwa ziqondakala kulula uma ucabangela isimo esiveza lokhu. Ngokwesibonelo, amaqanda ezinye stsifomeduz izabelo eyindilinga futhi kahle ephawulekayo cytoplasm: aminyene futhi zibe nezinhlamvu (ectoplasm) kanye neselula (endoplasma). Basuke izimpawu ukwahlukana kuqhathaniswa iyunifomu zokuvumelanisa: 2, 4, 8, 16. Ekugcineni igciwane liqukethe 32 blastomere. Ngaphezu kwalokho, division wenziwa parallel ebusweni umbungu. Kuvele olwelwesini kwakhiwa blastomeres ehlanganisa ectoplasm futhi yangaphakathi - wengxenye ectoplasm futhi endoplasmic. Ngamanye amazwi, lo multilayer nucleation nqubo by yehlukanise isendlalelo esisodwa ku amaseli ezimbili. Khona-ke, kuphela blastomeres yangaphakathi ochotshoziwe futhi zifana kuya ebusweni umbungu, okuyinto ngenxa uhlobo enjalo gastrulation ozuza umumo eyindilinga. Siqukethe flat 64 Ubumba yi-ectoderm amaseli 32 kanye convex, okuyisisekelo endoderm isisekelo.

Epibolicheskaya gastrula

Ezilwaneni nge evelele telolecithal isakhiwo amaqanda (isikhuphasha offset isigxobo vegetal), gastrulation kwenzeka epibolicheskomu imfashini. Macromers kukhona blastomeres ezinkulu ezihlukanisa kancane kakhulu futhi aqukethe semali isikhuphasha. Abanalo ikghono, kule ndaba, babungamahora "ukukhasa" micromeres bakhuthele elise phezu kweseli. Nge gastrulation enjalo blastopore ngingekho futhi archenteron hhayi kwakhiwa. kamuva kuphela, lapho macromers okwamanje encishisiwe ngobukhulu, ke uqala ukwakha umgodi, igciwane wamathumbu eyinhloko.

involution

gastrulation Involutional - inqubo ukuthi siqukethe in the "eneka" kwamaseli yangaphandle ngaphakathi umbungu kumiswa. Yena liyakhula ngobukhulu, kwelula kanye ebusweni engaphakathi. Le ndlela kuyisici sobuntu gastrulation mezoletsitalnymi izilwane nge amaqanda - Amphibia (izilwane zasemhlabeni). Yisa phambili onqenqemeni endaweni kwamaseli ezijulile kuvimbela archenteron ukuthuthukiswa. Kuzo kukhona yisandla ka involution.

Imodi okuxubile gastrulation

Njengoba yaziwa, embryogenesis - ziyinkathi zokuqala ekuthuthukiseni ngakunye umzimba ngamanye kusukela uqala ukwenziwa kuze lokuzalwa. Gastrulation ingenye ezigabeni, umlando yesibili ngemva kwasani. imikhondo yakhe ezahlukene ukuze zikwazi kungaba kuqhathaniswa ngezinga elikhulu conditionality. Ngayinye yalezi kudinga ukutadishwa nokuhlaziya. Nokho, kusenomsebenzi omkhulu umugqa ezithile empambana phakathi kwalezi ezimbili. Ngakho, njengoba uhlobo samuntu kungase kubhekwe inqubo invagination epiboly futhi delamination has ukufana ne wezifiki.

Qaphela ukuthi izilwane eziningi gastrulation kuyindlela elihlangene. Ezimweni ezinjalo zenzeka kanyekanye epiboly futhi intussusception, nezinye izinqubo morphogenetic. Ikakhulukazi, kuba ngakho gastrulation kwenzeka izilwane zasemhlabeni. Kule ndaba, abalobi abaningi ukukhomba indlela okuxubile.

gastrula

Ngokwezwi nezwi igama elithi Latin elithi "gastrula" lihunyushwa ngokuthi "esiswini, esiswini". Limelela isigaba ethize yentuthuko embryonic eziphilayo ezinamangqamuzana amaningi. Isici esiphawulekayo gastrula - kuba phambi ezimbili noma ezintathu zamatshe lwegciwane. Inqubo lasungulwa - lwesigaba of gastrulation.

Idivayisi elula ibhekwa kusukela abamele coelenterates izilwane. Basuke izimpawu gastrula ukuma ellipsoidal nge ungqimba unicellular yangaphandle (yi-ectoderm) kanye ekuqongeleleni yangaphakathi lamaseli (endoderm), kanye "esiswini eyinhloko". Ejwayelekile kubhekwe gastrula sea urchin, ezakhiwe invagination okuyinto. I gastrulation umuntu ethatha indawo 8-9 ngosuku th yentuthuko. Gastrula kuyinto esiyisicaba kwediski efana ukwakheka kwakhiwa kusukela le ngxenye engaphakathi yengqamuzana.

Njengomthetho, iningi izilwane embryo gastrula esiteji abakwazi ukuphila ngokukhululeka futhi esibelethweni, noma nolwelwesi amaqanda. Nokho, kunokuningi okungakhulunywanga ngakho. Ngakho, izibungu coelenterates planuly ukumela khulula-gastrula.