Physiology and biochemistry in modern medicine . : (1) as a slowly advancing con-traction (1 to 2 cm. per minute), preceded by an inhibition of the walls,and proceeding only through a short distance in a coil (4 to 5 cm.); and 466 DIGESTION (2) as a swift movement called the peristaltic rush, which sweeps with-out pause for much longer distances along the canal. Further analysis of the peristaltic wave can readily be made by theballoon method (Fig. 162). If the gut is pinched above the balloon, amarked relaxation occurs over it, and this relaxation extends for abouttwo feet down the intestine.
Physiology and biochemistry in modern medicine . : (1) as a slowly advancing con-traction (1 to 2 cm. per minute), preceded by an inhibition of the walls,and proceeding only through a short distance in a coil (4 to 5 cm.); and 466 DIGESTION (2) as a swift movement called the peristaltic rush, which sweeps with-out pause for much longer distances along the canal. Further analysis of the peristaltic wave can readily be made by theballoon method (Fig. 162). If the gut is pinched above the balloon, amarked relaxation occurs over it, and this relaxation extends for abouttwo feet down the intestine. If. on the other hand, the gut is pincheda little below the situation of the balloon, a long-continued contractionoccurs over the latter. The conclusion that we may draw from this resultis that the stimulation of the gut causes contraction above the point stimulus and relaxation below, this being known as the law of theintestine—(Bayliss and Starling). We have seen that it applies also inthe case of the cardiac and pyloric Fig. 162.—Intestinal contractions f balloon method) after excision of the abdominal ganglia andsection of both vagi. Mechanical stimulation above (/) and below O) the balloon causes relaxa-tion and contraction respectively. (From Starling.) The Physiologic Nature of the Rhythmic and Peristaltic Movements Interesting information in this connection has been gained by obser-vation of the behavior of the movements after the application of drugsto the gut or after cutting the nerve supply. The rhythmic movementsare not affected by the application of nicotine or cocaine. Since thesedrugs paralyze nervous structures it has been concluded that the rhythmicmovements are myogenic in origin. The question is not a settled one,however, for it has been found by Magnus that, although strips of thelongitudinal muscle, isolated in oxygenated saline solution, will continueto beat, they do not do so if the adherent Auerbaclrs plexus of nervesis stripped
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