Gastrulation - shi ... A samuwar Multi-mai lebur tayi

Blastula, wanda kuma ake kira germinal kumfa, shi ne karshe sakamakon crushing qwai. Next mataki bayan shi, bautar wani tsaka-tsaki matsayi tsakanin crushing da organogenesis, embryogenesis ne gastrulation. Its ma'anar asali ne samuwar na uku jam yadudduka: indodem, da kuma mesodam ectoderm. A wasu kalmomin, shi gastrulation fara da tayi morphogenesis da bambantawa na wani kwayoyin.

A definition of "gastrulation"

Ko da baya a 1901 gastrulation da aka bayyana a matsayin hanyar da tayi a cikin fall mesodam, da indodem, da ectoderm Kwayoyin. Wannan yakan haifar da definition da wanzuwar musamman blastula organoobrazuyuschih sarari. Farga da shi da kyawawan sauki description, shi ne mai sauki su matsa zuwa wani karin hadaddun, na zamani ma'anar da kalmar. Gastrulation - shi ne jerin morphogenetic ƙungiyoyi da cewa haifar a cikin yunkuri na rudiments na masana'anta a wuri sanya musu daidai da "shirin" na kungiyar na jiki. Tsari hadaddun canje-canje suna tare da girma da kuma haifuwa, directional motsi da kuma bambance na sel.

Ganin gastrulation a mafi janar ji, shi za a iya ƙaddara a matsayin tsaka-tsaki mataki, na zuwa wani guda tsauri tsari, a lokacin da rearrangement sassan blastula, wanda muhimmanci facilitates aiwatar miƙa mulki ga organogenesis.

motsi Kwayoyin

Idan ka ba mai janar bayanin irin tsari karkashin shawara, zamu iya cewa gastrulation - shi embolism da epiboly. Dukansu sharuddan daidai da morphogenetic ƙungiyoyi na Kwayoyin, wanda ya auku da cikakken a duk matakai na ontogenetic ci gaban da kwayoyin. Duk da haka, suna mafi furta a lokacin da shi gastrulation. Epiboly kira aiwatar da motsi a kan surface na cell tsakiya, da kuma embolism - su motsi ciki da shi.

A embryology bambanta da wadannan main iri gastrulation ko cell motsi: intussusception, shige da fice, involution, delamination da epiboly. Don ƙarin bayani game da su - daga baya a cikin labarin.

Motsi cell yadudduka

Shiga a cikin aiwatar da gastrulation ba zai iya kawai ware (ƙaura yardar kaina) Kwayoyin, amma kuma dukan cell zanen gado. The shugabanci ne niyya da kuma m m interactions. A farko sojojin bude P. Weiss a cikin 20s na karshe karni da hali ya bayyana su zama a embryogenesis, na biyu - a rare da kuma musamman, a al'ada morphogenesis faruwa tare da low yiwuwa.

Lokacin da gastrulation cell fragmentation ya auku. Kamar yadda riga aka ambata a sama, da motsi ya fara da cell talakawa a sakamakon samuwar biyu-Layer tayi kira gastrula. Zama a fili bayyane indodem da ectoderm. All kwayar kwayoyin (sai dai kawai coelenterates) gastrulation layi daya tare da ko nan da nan bayan an kafa germinal uku leaf kira mesodam. Yana da wani tarin Kwayoyin dake tsakanin indodem da ectoderm. A sakamakon haka, amfrayo zama uku-Layer.

Hanyoyin da gastrulation ne kai tsaye dogara a kan irin blastula.

invaginated gastrula

Hanyar sunan yayi magana don kansa. Intussusception - guda-Layer bango invagination na blastula (balstodermy) cikin blastocoel. A mafi m, kuma mafi bayyananne misali ne a roba ball. Ta danna kan abu shi ne guga man baxini. Invagination za a iya kawo wa mafi bango ko yin shi kaɗan. A sakamakon haka ne canji na blastula da gastrula an samu matsayin dual Layer jakar archenteron. Its ciki bango ne na farko da indodem, da m - primary ectoderm. A sakamakon cikinsa archenteron (primary hanji) na Magana da waje ta hanyar ramukan, kira blastopore. Na biyu sunan - da farko bakinka. Its kara ci gaba da dogara a kan irin kwayoyin. A dabbobin da yawa da blastopore ƙarshe tuba zuwa tabbatacce bakinka. A wannan batun, sun kira protostomes (molluscs, tsutsotsi, arthropod). A deuterostome blastopore tuba zuwa neuro-hanji bututu zubar a raya wani bangare na cikin tayi (a chordates) ko dubura.

shige da fice gastrula

Shige da fice gastrulation - a Hanyar da su kafa wata biyu Layer amfrayo, mafi halayyar coelenterates. Gastrula aka kafa ta da wani aiki part daga cikin blastocoel na blastula Kwayoyin. Wannan shige da fice ne unipolar a yanayi. Sel matsawa kawai tare da vegetal iyakacin duniya. Daga baya sai suka samar da indodem, t. E. Ciki Layer. Wannan shi ne hanyar gastrulation faruwa a hydroids jellyfish.

blastoderm Kwayoyin a cikin blastocoel iya shiga ba, kuma bã da wani daya yankin, amma a kan dukan tayi surface. Wannan shige da fice da aka kira multipolar, amma same shi quite rare.

Mutane da yawa coelenterates, wanda shi ne peculiar zuwa shige da fice hanyar gastrulation auku sosai aiki "kore" na sel blastula da gastrula, kafa a sakamakon, hasarar blastocoel. A wannan yanayin, da halayyar for baya Hanyar invaginated blastopore offline.

Delaminatsionnaya gastrula

Wannan rare jinsunan da aka yi da farko aka bayyana a gastrula Mechnikovym I. I., kuma shi ne na hali na coelenterates. Rakiyar gastrulation matakai ne sosai peculiar, amma su ana tsinkayarsu sauki a lokacin da la'akari da wani hali hali. Alal misali, qwai da wasu stsifomeduz da concentric da kyau jinsin rabo daga cikin cytoplasm: m da grainy (ectoplasm) da kuma salon salula (endoplasma). Suna halin a gwada uniform da synchronous division: 2, 4, 8, 16. qarshe jam ƙunshi 32 blastomere. Bugu da ari, division aka yi a layi daya zuwa surface amfrayo. An m Layer kafa blastomeres kunshi ectoplasm da ciki - na ɓangare na ectoplasm da endoplasmic. A wasu kalmomin, da multilayer nucleation tsari ne da tsagawa guda Layer cikin biyu Kwayoyin. Sa'an nan, kawai ciki blastomeres murƙushe da kuma sake layi daya zuwa surface amfrayo, wanda yake shi ne sakamakon irin wani irin gastrulation yakan mallaki wani mai siffar zobe siffar. Ya ƙunshi wani lebur 64 kafa ectoderm Kwayoyin 32 da kuma convex, wanda samar da tushen indodem.

Epibolicheskaya gastrula

A dabbobi da pronounced telolecithal tsarin qwai (gwaiduwa biya diyya ga vegetal iyakacin duniya), gastrulation auku epibolicheskomu fashion. Macromers ne manyan blastomeres cewa raba sosai sannu a hankali da kuma dauke da wani babban adadin da gwaiduwa. Bã su da wani ikon motsa, a wannan batun, suka zahiri "ja jiki" mafi aiki micromeres located a kan salula surface. Tare da irin wannan gastrulation blastopore fakowa ba da archenteron ba kafa. Kawai daga baya, lokacin da macromers tukuna rage a cikin size, shi zai fara samar da wata rami, da jam na farko hanji.

involution

Involutional gastrulation - wani tsari da ta ƙunshi a cikin "fallasa" na cikin matsanancin Kwayoyin baxini tayi samuwar. Ya na karuwa a size, kara tare da ciki surface. Wannan hanya ita ce halayyar gastrulation mezoletsitalnymi dabbobi da qwai - Amphibia (halittar dabba mai kafafuwa). Matsar da manyan baki yankin na zurfin Kwayoyin damuarn cin gaban archenteron. A cikinsu ta'allaka da tuki da karfi na involution.

Mixed yanayin na gastrulation

Kamar yadda aka sani, embryogenesis - shi ne farkon lokaci na ci gaban kowane mutum kwayoyin daga ganewa to haihuwa. Gastrulation ne daya daga cikin matakai, na biyu tarihi bayan crushing. Ta hanyoyi ne don haka daban-daban da cewa suna iya zama idan aka kwatanta da manyan digiri na conditionality. Kowace daga cikin wadannan na bukatar wani cikakken nazari da bincike. Duk da haka, har yanzu akwai wani layin na mahada tsakanin biyu. Saboda haka, kamar yadda wani irin embodiment za a iya daukarsa invagination aiwatar epiboly da delamination yana da kamance da shige da fice.

Ka lura da cewa a cikin dabbobin da yawa gastrulation ne a hada hanya. A irin haka ne faruwa lokaci guda epiboly da intussusception, da kuma sauran morphogenetic tafiyar matakai. A musamman, shi ne don haka gastrulation auku a halittar dabba mai kafafuwa. A wannan batun, mawallafa, da dama gane gauraye Hanyar.

gastrula

Zahiri Latin Kalmar "gastrula" da aka fassara a matsayin "ciki, ciki". Yana wakiltar wani takamaiman mataki na amfrayo ci gaban kwayar kwayoyin. A rarrabe da gastrula - shi ne gaban biyu ko uku jam yadudduka. A tsari na da samuwar - wani lokaci na gastrulation.

Mafi sauki na'urar da aka kyan gani daga cikin wakilan coelenterates dabbobi. Suna halin gastrula ellipsoidal siffar da unicellular m Layer (ectoderm) da kuma ciki jari na sel (indodem), da kuma "primary Gut". Hankula dauke gastrula teku urchin, wanda aka kafa ta invagination. Mutumin gastrulation faruwa a ranar 8-9 ga watan rana na ci gaba. Gastrula ne flattened faifai-kamar samuwar kafa daga ciki cell mass.

Matsayin mai mulkin, mafi yawan dabbobi a cikin gastrula mataki tayi ba zai iya rayuwa da yardar kaina da kuma shi ne a cikin mahaifa, ko da kwai membranes. Duk da haka, akwai ban. Saboda haka, larvae coelenterates planuly wakiltar free-gastrula.