Gastrulation is ... Nzira yekuumbwa kwe multilayer embryo

Blastula, inonziwo chivako chinonzi embryonic, ndicho chigumisiro chekupedzisira chekugadzirisa mazai. Chikamu chinotevera, kutora nzvimbo yepakati pakati pekupwanya uye organogenesis, kugadzirisa mu embryogenesis. Chinangwa chayo chikuru ndechekuumba nhatu mavara mashizha: endoderm, ectoderm uye mesoderm. Mune mamwe mazwi, zvinoreva kugadzirisa kuti embryonic kusiyana uye morphogenesis yemuviri inotanga.

Tsanangudzo yezwi rokuti "gastrulation"

Kudzoka muna 1901 gastrulation yakatsanangurwa senzira iyo ma mesodermal, endodermal uye ectodermal cells dzinopinda mu embbryo. Iyi tsanangudzo inoreva kuvapo kwe blastula nzvimbo dzakasiyana-siyana. Sezvo wanyatsonzwisisa tsanangudzo iyi iri nyore, zviri nyore kuenda kune imwe yakaoma, zvinoreva zvemazuva ano. Gastrulation ndeyekuenzanisa kwemafungiro e morphogenetic, mugumisiro waro ndiko kufamba kwezvinyorwa zvemashutu kune nzvimbo dzavakatarirwa maererano ne "chirongwa" chekusangana kwehupenyu. Iyo nzira yakaoma, kuchinja kunofambidzana nekukura uye kuwedzera, kutungamirirwa kufamba nekusiyaniswa kwemasero.

Tichifunga nezvekuita gastrulation nenzira yakajeka, zvinogona kuitsanangura sechikamu chepakati chechimwe chinhu chakasimba chekuita panguva iyo blastula zvikamu zvinovakwazve, izvo zvinoita kuti zvive nyore kuchinja kune inonzi organogenesis.

Kufamba masero

Kana tikapa tsanangudzo yakawanda yehutano huri pasi pekufungisisa, saka tinogona kutaura kuti gastrulation is embolism uye epiboly. Zvose zviri zviviri zvinoratidza kufamba kwemaitiro emafungiro emuviri, anowanikwa zvachose pamatanho ose ekugadzirwa kwegunyiko kwechimiro. Zvisinei, ivo vanonyanya kuzivikanwa apo gastrulation. Epibolia ndiyo nzira yekufambisa masero akakomberedzwa nechokumusoro kwemukati, uye embolism ndiyo kufamba kwavo mukati maro.

Mu embryology, inotevera mikuru mikuru yekuita gastrulation kana sekufambisa kwesero inozivikanwa: kuvhara, kutama, kutendeuka, delamination uye epiboly. Mamwe mashoko pamusoro pavo - gare gare munyaya.

Kufamba kwezvikamu zvemasero

Haisi kungoparadzaniswa chete (kusununguka kuenderera mberi) masero anogona kubatanidzwa mukugadzirwa kwegastrulation, asiwo mazamu ose emasero. Nhungamiro inotarisa kusanganisa nguva dzose uye kure. Hondo yekutanga yakawanikwa naP. Weiss muma1920 uye zvinoitawo kuti inowanikwawo embryogenesis, iyo yekupedzisira - isingawanzo uye yakakosha, uye inowanzoitwa morphogenesis inowanikwa nekadiki zvishoma.

Pakugadzirisa, kuparadzaniswa kweyero hakuiti. Sezvatotaurwa pamusoro apa, kufamba kwemasero masero kunotanga uye, somugumisiro, kuumbwa kwemaviri maviri akareruka anonzi gastrula. Anova pachena zvakajeka endoderm uye ectoderm. Muzvipenyu zvose zvakasiyana-siyana (kunze kwei-coelenterates), zvakafanana nekugadzirisa, kana pakarepo mushure maro, jira rechitatu remashizha, rinonzi mesoderm, rinoumbwa. Iko kuunganidza kwemasero ari pakati pe ectoderm uye endoderm. Somugumisiro, embryo inova mitatu-yakavezwa.

Nzira dzegastrulation dzinotarisana nemhando yeblastula.

Invagination gastrula

Zita renzira yacho rinotaura pacharo. Invagination ndiko kupindira kwemasvingo akare-akavhara blastula (ballosterma) mukati me blastocoel. Iyo yakanakisisa uye yakajeka ndeye muenzaniso ane rubber ball. Paunenge uchinyora, mamwe emashoko acho akaomeswa mukati. Kuiswa mukana kunogona kuendeswa kumadziro akareba kana kuti kushandiswa kusina basa. Somugumisiro, blastula inoshandurwa, uye gastrula inowanikwa se-two-layer bag ne archenterone. Rusvingo rwaro rwomukati nderokupedzisira endoderm, uye rusvingo rwokunze ndiyo yekutanga ectoderm. Iyo archenterone (intonde yemukaka) yakadaro yakaumbwa inotaurirana nenzvimbo yekunze kuburikidza nehomwe inonzi blastopore. Zita rechipiri ndiyo inonyanya kutaura muromo. Kubudirira kwaro kunoenderana nemhando yehupenyu. Mhuka dzakawanda, blastopore inozopedzisira yava kuchinja mumuromo. Munyaya iyi, inonzi "primary moles" (mollusks, worms, arthropods). Muchikamu chechipiri-chengeteredzwa, inoshanduka kuva mutsara wesimbi uri mu posterior chikamu chema embryo (mukugunun'una) kana mune anus.

Immigration gastrula

Kuenda kune imwe nyika gastrulation ndiyo nzira yekuumbwa kwemaviri-akareruka embryo, maitiro akawanda e-coelenterates. Gastrul inoumbwa nokushingaira kubvisa chikamu chemasero e blastula mu blastocoel. Kuenda kwakadaro kune unipolar. Maseji anongobva chete kubva pamiti yemiti. Pave paya vanogadzira endoderm, kureva, mukati memukati. Ndiyo nzira iyi iyo gastrulation inowanikwa mu hydroid polyp, jellyfish.

Mitsara ye blastoderm mu blastocoel inogona kupinda munzvimbo imwe chete, asi pamusoro pemusoro wose we embryo. Kutama kwakadaro kunonzi multipolar, asi hazvisi nyore.

Mune mazhinji coelenterates, ayo anozivikanwa nenzira yekufambisa yekugadzirisa, kune "kusunungurwa" kwakasimba kwemasero e-blastula, uye gastrula, yakagadzirwa semugumisiro, inopera zvachose blastocoel. Muchiitiko ichi, blastopore, iyo inofanirwa nenzira yekare yekugadzirisa, haipo.

Delamination gastrula

Izvi zvisingawanzoitiki zvegastrula zvakatanga kurondedzerwa naMechnikov II, uye iyo inofanirwa ne coelenterates. Izvo zvinowirirana nekugadzirisa zvinhu zvakanyanya, asi paunofunga nezvechiitiko chaicho, zvinonzwisisika zviri nyore. Semuenzaniso, mazai emamwe sciophedus ane zvikamu zvakajeka uye zvakajeka zvikamu zve cytoplasm: dense uye granular (ectoplasm) uye masero (endoplasm). Izvo zvinoratidzirwa nemaitiro akafanana uye akafanana: 2, 4, 8, 16. Pakupedzisira, embryo ine 32 blastomeres. Uyezve, kupatsanurwa kunoitwa zvakafanana nepamusoro pepamuro. Nzvimbo yekunze ye blastomeres ine maitiro ectoplasm uye mukati mecherechedzo inowanikwa kubva kuEctoplasm uye kubva kumapoplasm. Mune mamwe mazwi, nzira yekuumbwa kwema-mullayer embryo inowedzera nekuparadzanisa imwechete yemasero muviri. Zvadaro bedzi blastomeres mukati memhepo inopwanyika uye zvakare yakafanana nepamusoro pepamuro, iyo, semugumisiro wekugadzirisa kwakadaro, inowana maitiro ebhora. Iyo inosanganisira 64 ectoderm-yakagadzira masero akapfigira uye 32 mamwe maonero emagetsi, ayo ndiwo mavheti ekupedzisira.

Epibolic gastrula

Mhuka dzine chimiro chechimiro chemazai (kushanduka kwejikiti kusvika paduru), gastrulation inoitika maererano neEpibolic method. Macromers akawandisa blastomeres, ayo akaparadzaniswa zvishoma nezvishoma uye ane zvakawanda zve yolk. Vachishaya kukwanisa kufamba, maererano neizvi, ivo "vanocheka" mamwe maitiro emagetsi ari pamusoro penhare. Nekugadzirisa kwakadaro, blastopore haisipo, uye archenterone haina kuumbwa. Kungozotevera, apo macromeres ano ichiri kuderera muhukuru, chivako, chirevo chemukati wemukati chinotanga kuumbwa.

Involution

Kugadziriswa gastrulation ndiyo nzira ye "tucking" iyo yakasara yemasero mukati memukati embryo. Inowedzera muhukuru, inopararira mukati memukati. Iyi nzira yegastrulation inozivikanwa nemhuka dzine mesolecitic ovules - amphibians (amphibians). Kuparadzanisa kwemasero akadzika anotungamirira emunharaunda yakadzika kunobvisa kugadzirwa kwe archenterone. Icho chiri mavari icho chinokonzera kushanduka kwenhema.

Mixed mode ye gastrulation

Sezvinozivikanwa, embryogenesis ndiyo nguva yekutanga yekubatsira kwemunhu umwe neumwe: kubva pamuviri kusvikira pakuzvarwa. Gastrulation imwe yezvikamu zvayo, yechipiri mukuverenga nguva pashure pokupwanya. Nzira dzayo dzakasiyana kwazvo zvokuti iwe unokwanisa kuzvienzanisa nehurukuro huru yekokorodzano. Chimwe nechimwe chazvo chinoda kunyatsodzidza nekuongorora. Zvisinei, pane zvimwe zvikamu zvakananga zvekubatana pakati pavo. Saka, sechimiro chekuisa mukana munhu anogona kufunga nezvekuita kwe epiboly, uye delamination inofanana nekuenda kune dzimwe nyika.

Cherechedza kuti mhuka dzakawanda dzine gastrulation nenzira yakabatana. Mumamiriro ezvinhu akadaro, epiboly uye kupindira kunoitika panguva imwechete, pamwe chete nedzimwe marphogenetic michakato. Kunyanya, iyi ndiyo nzira yekuita gastrulation kunoitika mumamphibians. Munyaya iyi, vanyori vakawanda vanosiyanisa nzira yakakanganiswa.

Gastrula

Izvo muchiLatin, izwi rokuti "gastrula" rinoshandurwa se "mudumbu, mudumbu." Inoreva chikamu chakanaka mukukudziridza kwemazamu emarudzi akawanda. Chinhu chakasiyana che gastrula ndekuvapo kwemashure maviri kana matatu emashiripiti. Iyo nzira yekuumbwa kwayo ichine chikamu chegastrulation.

Icho chinhu chakareruka chinowanikwa muvamiri ve coelenterates . Iyo inoratidzwa neallipsoidal gastrula ine unicellular outer layer (ectoderm) uye inopindirana kusangana kwemasero (endoderm), pamwe ne "primary" mumvura. Chimiro chegastrula chegungwa urchin, iyo inoumbwa nekugadzirisa, inofungidzirwa. Mune vanhu, gastrulation inoitika musi we8 kusvika ku 9 wekufambira mberi. Gastrula ipangwana rakagadziridzwa, rakagadzirwa kubva mukati memukati masero.

Sezvo mutemo, mumhuka dzakawanda pane gastrula nzvimbo iyo embryo haigoni kurarama pachena uye iri muchibereko kana muzamu membeu. Zvisinei, kune zvimwe. Saka, iyo inokonzera maruva, mapurisa, anomiririra gastrula yakasununguka.