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).
1 Flexion takes the embryo from a flat disk to its basic embryonic body form. The primitive gut originates from entoderm at the time of its flexion.  The yolk sac constricts, thus the intraembryonic entoderm (future digestive tube) and the extraembryonic entoderm (forms the inner lining of the yolk sac) are delineated.