restriction. n. 1. something that restricts; a restrictive measure, law, etc. 2. the act of restricting or the state of being restricted. 3. (Logic) logic maths a condition that imposes a constraint on the possible values of a variable or on the domain of arguments of a function.
The primitive gut that forms during gastrulation in the developing embryo is known as the archenteron or the digestive tube.It develops into the digestive tract of an animal.ach is controlled by the dorsal blastopore, and primitive node (also known as Hensen's node), respectively. During Gastrulation, the Archenteron develops into the digestive tube, with the blastopore developing into either the mouth (Protostome) or the anus (Deuterostome).
The primitive streak originates from the anterior epiblast, and appears as an elongating groove (primitive groove) on the dorsal midsagittal surface of the epiblast, along the anterior-posterior axis of the embryo. The rostro-caudal and medial-lateral axes of the embryo are defined by the primitive streak.The rounded primitive node, or Hensen's node, is situated at the cranial tip of the primitive streak, and contains a depression called the primitive pit.mbryonic Derivatives of the Primitive Streak: Cells from the epiblast migrate into the interior of the embryo via the primitive streak, in a process termed ingression, which involves a cellular epithelial-to-mesenchymal transition (EMT).