Neurula - isigaba lophuhliso umbungu

Enye namaxesha kuphuhliso ngamnye eziphilayo - ontogenesis yi embryogenesis. Oku kuquka ixesha ukususela ekuqaleni lokusekwa elilodwa phambi kokuzalwa inyama yaye iquka izigaba ezininzi ngokulandelana abadlulayo. Omnye wabo neurula. Eli nqanaba uphuhliso ekuyo, nto leyo ekhokelela ukuba ukuyilwa ndiseyimbumba, ukuba ngeengcamba ezintathu intsholongwane, kwakunye uvaleke. Ngaphezu koko, ngokuba iiveki eziliqela kwi ndiseyimbumba akhiwa ngayo izinto eziphambili noshowo yonke le nkqubo engundoqo neuropathy luvo. Kweli nqaku siza kuqwalasela iimpawu zombini kweqonga kunye nokomzimba ezenzeka kuyo.

Izigaba zophuhliso osandul

ezincancisayo placental elipheleleyo efanayo atsho elilodwa, eziquka abantu, oko kukhokelela isakhiwo elijongeka yemibhaka berry okanye anambitheka. Ibizwa ngokuba morula. Ke zaso ezicwangciswe umaleko mnye, uMbumbi blastula. Le bag ezibuhlazarha, iindonga apho akhiwa blastomeres-iiseli. Okulandelayo, inkqubo invagination, neziphumo ukuvela maleko kabini le mveku. Nguwo lo gastrula isigaba. Le ibandakanya ectoderm kunye endoderm, kwaye umlomo ephambili, ebizwa umlebe le blastopore. Kamva iikona ezo zivaliweyo, mbungu ngokohlobo maleko kabini le bag. iingxaki ezalandela emva koko ekwabhengezwa lwesakhiwo umbungu enxulumene imbonakalo komnye, owesithathu, umaleko germinal - mesoderm lulele phakathi ecto- kunye endoderm. yemfundo yakhe e embryogenesis yabantu ezichaphazela yayo. Siza kufunda ngayo ngokweenkcukacha.

ekumisweni mesenchyme

Umbungu ngandlela yayo kwisisu bodwa iinkqubo osisi - somites okanye ipokotho. Bona zivela eludongeni ethunjini kwakudala. Ukususela mesoderm elisakhulayo yaye somites ukuba ukhonza njengomnqophiso organogenesis phezulu. Kwasekwa inkqubo izakhiwo ibalulekileyo: notochord, amathumbu kunye uvaleke. Zibizwa ngokuba amalungu yezihlunu. Lwegciwane lwe nzima nesakhiwo sayo, benza iqonga elitsha - neurula. Kuthatha indawo nge-3 - kweeveki ezi-4 zokukhulelwa. Le indlela ukuyilwa uthe Inqanaba imveku ephakamileyo kuxoxwe ngokubhekele phaya.

Njengoko umbungu kubonakala uvaleke

I Iphepha engaphandle germinal - ectoderm, kwicala amanakani okuba i yosana olungekazalwa uba zamahlathi ngakumbi zamafu, yazinyusa iguqulelwa kwipleyiti uvaleke. Iikona yayo bayavuswa, ukwakha roller ezimbini. Phakathi kwazo kukho lijelo elisetyenziswa, kamva zibe em- ingqondo kunye umnqonqo ezaliswe utywala. ipleyiti zobuchopho iwa emiphethweni yayo, okokuqala kummandla wesibeleko ze ndiseyimbumba, umbungu uze emva ngaphaya esqwini umzimba. Igcina nokuvalwa kwipleyiti uvaleke kwinxalenye cranial apho ingqondo asakhasayo vesicles - nokuqala ingqondo. Awu 4 zokukhulelwa, uvaleke yi eyahlukanisiweyo ngokupheleleyo ukusuka ectoderm. Ngenxa uvaleke kwasekwa iiseli zemithambo-luvo kunye izihlunu trophic - kwenzeka neurula kunye neuroglia. Eli nqanaba uphuhliso osandul, equka ngongqameko lwegciwane ezintathu uvaleke. unako kuwo wabumba njani luvo zabantu?

Indima zobuchopho Crest, uluhlu luvo

Ngoko nangoko emva kokuba izileyi ukudibanisa sabonakala uvaleke kwi izabelo esembindini kunye ectoderm cutaneous ukwahlula iqela leseli. Le ibekwe ecaleni ezimanyeneyo umzimba umbungu phakathi zangaphandle kunye ityhubhu osandul uvaleke kuthiwa Crest uvaleke. sezulu cellular inenye into eyahlukileyo. Oku - ukukwazi ukuba bafudukele kwiindawo ezahlukeneyo umbungu. Ngokomzekelo, ezinye iiseli umbungu singena nzulu emzimbeni kunye nefom neurocytes kunye neuroglia ganglia yoqhekeko novelwano kunye parasympathetic inxalenye engabalulekanga luvo. Ezinye iiseli bahlale Crest uvaleke, ekuqaleni kusekwe macwecwe ganglion, ezithi ke ngoko similise iindawo 31 izibini luvo lialio. Kule nkqubo neurulation awuphelelanga kwaye kukho ukuphucuka ngakumbi kwezahlulo nkqubo engundoqo neuropathy luvo.

I ubuxhakaxhaka isakhiwo Umbungu lo neurula isigaba

Zifuduka iiseli Crest, umbefu, ukusukela isabelo eliphakathi ecaleni kumacandelo intambo sacral kwi-27 - 28 somites, bayakwazi umahluko, oko kukuthi ngokuyimfuneko iiseli polustvolovym efanayo ezinomongo wethambo. Ukususela inxalenye elandelayo diencephalon kwikhadi umbungu sacral kwi-27 - 28 bengababini somite, ukuyilwa neurocytes abaqolileyo neeseli glial ye-luvo cranial kunye ganglia le izixhobo eziviwayo kunye vestibular. Kweli nqanaba lophuhliso osandul kuluhlu ukusuka ku-1 ukuya ku-7 somite yezabelo Crest, umkhwetha ukuyilwa ganglia yawo innervating intliziyo, imiphunga, amathumbu kunye amaqumrhu isinqe mbungu. Gqibezela ekukhuleni luvo yi ukuya kwiiveki ezingama-40 zokukhulelwa.

Izizathu yokufuduka iiseli Crest umbefu

Ngokusekelwe kwiinkqubo kuxoxwe ngasentla e-nervous system, umbuzo yendalo umbuzo: ingaba ukuchaza indlela isizathu sokuba ihamba iiseli Crest, uvaleke imigama emide kumzimba olungekazalwa? embryology Modern lungisa them ngolu hlobo lulandelayo. Okokuqala, neurula - isigaba sokuba embryogenesis apho iiseli Crest, umbefu baphelelwe ngamandla abo ukubambelela, okt unxibelelwano nabanye ... Isizathu sesibini kuxhomekeke bamachiza ubume matrix extracellular bemveku. Le nto ndiyibhalayo hyaluronic acid kunye neeproteni: collagen, laminin, fibronectin ukuba tropism iiseli Crest uvaleke.

ulwalamano lwabo isizalo extracellular kunye yokufudukela kwenzeka ngenxa umqondiso molekyuli - integrins, kwakunye ubukho kwi somites neurula glycoproteins ezikhethekileyo: tenascin ne T-cadherin. Konke oku kuqinisekisa uphuhliso kwiindawo eziphambili e-nervous system yalo mbungu.