i III MECHANIC M OP DIG! 81 [I 



page 7%; endowed with the power of directing nervous imp 



bring about relaxation of the gul in front of the stimulus and conti 



tion over it. 



Nervous < Iontbol of Movemi - 



The influence of the central aervous system on the intestinal movenu 

 has been studied by the usual methods of cutting ;in<l stimulating the 

 extrinsic nerve supply. Through the splanchnic nen 

 impulses are conveyed to the intestine i :cep1 the ileocolic Bphincfc 

 for after these nerves are Bevered the movements become more distil 

 [ndeed, in many animals after opening the abdomen no intestinal mo 

 inent can be observed until these nerves have been cut. stimulation of the 

 peripheral end of the nerve also inhibits any movement which n 

 while be in progress. The impulses through the vagus nei 



Fig 1 3 Th of excitation of both splanchnic in 



Starling.) 



opposite character. Section of these nerves has little stimula- 



tion causes contraction. | Pigs. 163 ami 164. 



By observing the rhythmh ntractions of an isolated strip all 



intestine suspended in a bath of oxygenated saline BOlutioD at body tem- 

 perature, it can readily- be shown that the presence of even a mimn 



of epinephrine is sufficient to produce complete inhibition of tl 

 The parallelism between the effects of splanchnic stimulation and t ; 

 epinephrine injection is very significant, for in this way the marked inhi- 

 bition of intestinal movemenl which occurs during fright may poasiblj 

 be explained I Bee page 7 : 



The circular muscular coat of the last two Or tfw 

 the ileum before it joins the cecum is definitely thicker than the ■ 

 this coat, indicating thai it has a sphincter-like action. This . 

 sphincter, as it is called, opens when food i» pressed against it from the 

 ileum, but remains closed w hen food is pressed against it from the cecum. 



