GASTRULYATSIYA CHIST?

Blastula az miqdori ziyodi blastameraho iborat buda (masalan, dar neshtarshaklho az 3000 hujayra), dar rafti inkishof ba davrai nav meguzarad, ki gastrula (az yunoni gastro – meda) nom dorad. Dar in davra janin az qabathoi judo-shudai hujayragi – bargchahoi janin iborat ast. Qabati beruniro ektoderma (az kalimai yunonii ecto – berun) va daruniro entoderma (az kalimai yunonii ento – darun) menomand.

Majmui ravandhoe, ki bo paydoishi gastrula musoidat mekunand, gastrulyatsiya nomida meshavad.Dar neshtarshaklho gastrulyatsiya dar natijai furu raftani yak tarafi devorai blastula, ki dar natija javfi avvali jism paydo meshavad, ba vujud meoyad (rasmi 7.2).

Baroi isboti in guftaho tubi surokhshudai kudakonro misol meorem. Tubi rangini rezini az mobayn bo khat judo shudaast. Agar tubro tarze guzorem, ki shakli kosa paydo shavad, devorai on az du qabat iborat buda, ba shakli gastrulai neshtarshaklho monand meshavad. Dar in holat, vazifai ektodermaro qabati boloi va vazifai entodermaro qabati daruni (fururafta) ijro mekunad. Dar hayvonoti serhujayra, gayr az rudakovokho, barobari gastrulyatsiya qabati seyumi yo bargaki janin – mezoderma (az yunonii mesos – dar mobayn joy giriftan) niz paydo meshavad.

Mezoderma az majmui unsurhoi hujayragi, ki dar bayni ekto – va entodermai javfi avvalini jism joy dorand, iborat ast. Bo paydo shudani mezoderma janin seqabata meshavad (rasmi 7.3).

Hamin tavr, mohiyati ravandi gastrulyatsiya dar on ast, ki massai hujayraho bo ham omezish meyoband, vale hujayrahoi janini taqsim nameshavand va namesabzand. Dar hamin davra istifodai akhbori genetikii hujayrahoi janin sar shuda, alomathoi nakhustini tafriqashavi ba nazar merasand.