Mushohidahoi hujayratukhmi bordori qurboqqa imkon dodand, ki tarzi inkishofi hujayrahoi in yo on qismi janin omukhta shavand. Malum gardid, az hujayrahoe, ki dar blastula joyhoi munosib dorand, uzvhoi avvalin ba vujud meoyand. Hamchunin muqarrar shud, ki az kadom guruhi hujayraho naychahoi asab, khorda, mezoderma, epetiliyai pust paydo meshavand. Dar haqiqat dar organizmhoi qobili inkishof (vivo) az hujayrahoi muayyani ibtidoi uzvu boftahoi muay-
yan ba vujud meoyand, vale dar mavridi berun az organizm parvarish kardani hujayrahoi janin (dar probirka – vitro) onho in qobiliyatro gum mekunand.
Umumiyati khathoi uzvho dar neshtarshaklon:
A – gastrula, B, V – tashakkuli naychai asab, G – tashakkuli khorda, naychai ruda va mezoderma, 1 – ektoderma, 2 – entoderma, 3 – mezodermai ibtidoi, 4 – javfi ruda, 5 – qabati asab, 6 – naychai asab, 7 – khorda, 8 – javfi duyumini badan.