Kodi magawo a embryogenesis ndi ati?
Nthawi yamakono ya chitukuko mwa anthu imatenga miyezi iwiri - izi ndizomwe utali wa kusintha kwa mwana wosabadwa mu mwana wakhanda. Chifukwa cha njirayi, thupi limapangidwa lomwe liri ndi makhalidwe ofanana ndi a munthu wamkulu.
Pachiyambi choyamba, zygote amapangidwa. Amapangidwa chifukwa cha kusakanikirana kwa maselo amtundu wa amuna ndi akazi. Nthawi imeneyi ndi yaifupi. Pambuyo pofika siteji ya kugawidwa.
Panthawi imeneyi, kuchuluka kwa maselo ambiri kumachitika. Pachifukwa ichi, maselo omwe anapangidwa ndi kuphwanya amatchedwa blastomer. Choyamba, kusungunuka kwa maselowa kumapangidwa, komwe kumafanana ndi mabulosi a rasipiberi mu mawonekedwe ake akunja, ndipo amatchedwa morula. Powonjezera kwina, chiwerengero cha maselo chikuwonjezeka ndipo morula imatenga mawonekedwe ozungulira, blastula.
Pambuyo kupundula, yotsatira, gawo lachitatu la nthawi ya embryonic ya chitukuko cha zamoyo, ndizokhalitsa. Zimatenga kusintha kwa kamwana kamodzi kamodzi kokha, mwachitsanzo. Kulankhula mwachidule - pali kuphatikiza kwa zipolopolozo. Pankhaniyi, gastrula yokha ili ndi masamba awiri a embryonic, ecto- and endoderms. Pa chisinthiko cha zinthu zonse zamoyo, njira yowonongeka inakhala yovuta ndi mapangidwe a axial complex (a neural tube, axial mafupa, mitsempha), yomwe imayikidwa pambali ya m'mimba mwa tsamba lachitatu la embryonic.
Nthawi yachinayi ikuphatikizapo kudzipatula kwa ziwalo zikuluzikulu za ziwalo ndi ziphuphu, komanso kukula kwawo. Pamodzi ndi izi, pali mgwirizano wolimba wa ziwalo mu umodzi umodzi. Choncho, kuchokera kumbali yakunja ya endodermerm, mapangidwe a epithelial minofu yowonjezera chingwe chamagazi, komanso glands zake. Kuchokera ku mesoderm - minofu, komanso epithelium ya dongosolo la genitourinary, maseĊµera a ubongo. Mesenchyme imapanga mgwirizano, wotsekemera, mafupa, fupa.
Kodi kukhazikitsidwa kwa ziwalo ndi machitidwe akuluakulu zikuchitika bwanji?
Titatha kulemba ndondomeko yonse ya nthawi yamakono ya chitukuko, tidzafotokozanso kuti machitidwe ndi ziwalo zimapangidwa bwanji pa sabata lililonse. Choncho, kupweteka panthawi yopanga kamwana kamene kamakhala pafupifupi masiku 3-4. Panthawiyi, imayenda pamwamba pa miyendo yopita kumalo. Chifukwa cha kusweka kuchokera ku blastomeres yomwe ili pamtunda, chipolopolo chimapangidwa, chomwe chimagwira ntchito popatsa mwana wosabadwayo, trophoblast. Mababu a blastomere, omwe ali pakatikati, amapanga embryoblast, kuchokera pamene thupi la m'tsogolo likulengedwa.
Pafupi ndi sabata yachiwiri ya chiyambi cha chitukuko, mwanayo amalowa mu khoma la chiberekero. Pa nthawi yomweyi, mapangidwe a yolk ndi amniotic vesicles amachitika. Atapanga mesenchyme, amnion amapangidwa. Ichi ndi chimbudzi chomwe chimapanga thumba, ndipo kenako chimadzazidwa ndi amniotic madzi onse.
Pafupifupi sabata lachitatu la chitukuko cha emamoni, khungu lolemera la maselo akukula limamasulidwa kumbuyo kwa embryo. Zomwe zimatchedwa mutu wa mutu, kuphulika, zimapanga mimba yoyamba. Ndimapangidwe kameneka kamene kamapangitsa kuti mapangidwe oterewa akhale opangidwa ngati neural tube.
Pakadutsa masabata 4 osaphatikizapo ziwalo zowonjezereka, mimba imayamba gawo limodzi loyamba chifukwa cha kukula, mwachitsanzo. Zigawo zosiyana za thupi la fetal m'tsogolo zimapangidwa. Mofanana ndi izi, gawo loyamba la zochitika za organogenesis ndi histogenesis zimachitika.
Pa sabata lachisanu la mimba, zida za manja ndi miyendo zikhoza kufotokozedwa momveka bwino, ndipo pa sabata lachisanu ndi chimodzi miyendo imagawidwa m'magulu akuluakulu. Pafupifupi mapeto a masabata asanu ndi awiri atatha ku US, ndizotheka kuona zala zala. Kotero, sabata 8 (izi ndi nthawi yayitali yomwe ma embryon amatha), ziwalo za m'mimba zimatha.
Pofuna kuwonetsa magawo akulu a nthawi yamakono ya chitukuko, tiyeni tiwone pansipa tebulo limene amasonyezedwa.
