The duodenum is not a mere passage of food coming from the stomach (Saenko et al., 19900 a). but there is a well - known functional relationship between the pylorus and the duodeno - jejunal junction (OJ]) (Saenko et al., 1990· b). It has been established that evacuation of the duodenum was normally submitted to exponential law and depended on absolute quantity of food evacuated from the stomach (Saenko et al., 1989 • b). Moreover, optimal conditions for duodenal alimentation were reponed to depend on the coordinated activity of the stomach and duodenum (Kerlin et al., 1982; Quigley, 1987). Such coordination may result from synchronous activity of the pyloric sphincter and the OJJ. Whereas the activity of the pyloric sphincter was well described in the literature, information about the OJ] was limited
to external morphologic characteristics (Repcuic and Campeanu, 1981; Zypen and Reves, 1984). It has been suggested that the Treitz ligament, an important part of the DB, determined the opening of the DJJ angle. thus facilitating the emptying of the duodenal content into the jejunum (Repcuic and Campeanu, 1981). Furthermore.
the functional role of the Treitz ligament as an active regulator of solid food evacuation from the duodenum was studied (Saenko et at, 1989 • b), As regards the DJJ, it has been postulated that the DJI was probably a "functional" sphincter that provided coordinated activity of the stomach and duodenum (Read et aI., 1980; Virchenko et aI., 1993). The D11 was also considered. in addition to the Treitz ligament. as a valve that regulated the duodenal content emptying (Saenko et al., 1989 • a; Saenko et al., 1990 - a). To our knowledge. very little information. if any, dealt with the possibility of existence of an "anatomical" sphincter at the DJI. The present study was then undertaken to investigate that hypothesis. providing more coordinated activity of the stomach and duodenum, thus serving as one of the factors regulating the process of digestion and absorption of nutrients from the duodenum.