284 



DIGESTION 



rC 



wall (cf. page 288). But these movements are presided over and regulated 

 in many ways by the central nervous system. The very complicated relations 

 of the nerves concerned in this control will be evident from the scheme devised 

 by Openchowski (Fig. 114). 



The stomach receives its motor nerves in part from the vagus, in part from 



the sympathetic nerves. These 

 nerve paths have been fol- 

 lowed up to the cerebrum as 

 follows : 



a. The Cardia: (1) From 

 the region of the posterior cor- 

 pora quadrigemina constrictor 

 fibers run for the most part 

 through the vagi; some run in 

 the sympathetic paths, reach- 

 ing their destination by way of 

 the spinal cord and the fifth 

 to eighth thoracic roots, thence 

 through the two splanchnics. 

 In the thoracic sympathetic 

 the fibers are only sparingly 

 represented. (2) The cardia 

 is dilated by fibers which 

 emerge from that region of the 

 brain where the anterior lower 

 end of the nucleus caudatus is 

 united with the nucleus, lenti- 

 formis, and join the vagus. In 

 the spinal cord also as far as 

 the fifth thoracic root, there 

 are centers for the opening of 

 the cardia which send their 

 fibers by sympathetic pa'th- 

 ways. 



I. The Body of the Stom- 

 ach between the cardia and the 

 pylorus: (1) The brain centers 

 for the contraction of this 

 part, lie in the corpora quadri- 

 gemina, and the paths traverse 

 both the vagi (chiefly) and the 



FIG. 114. The nerves of the stomach musculature, 

 after Openchowski. Red, the paths to the cardia; 

 blue, the paths to the body of the stomach ; green, the 

 paths to the pylorus. C, the cerebrum; V, stom- 

 ach; MO, medulla; MS, spinal cord; 5-10, thoracic 

 roots; VRS, right vagus; VS, left vagus; ND, dilators 

 of the cardia; NC, constrictors of the cardia; a, 

 Auerbach's plexus; S, S, fibers from the sympathetic 

 plexus. 1, sulcus cruciatus; 2, corpus striatum; 3, 

 corpus quadrigemina; 4, centers in the spinal cord. 



spinal cord, thence by way of 



the lower thoracic cord through the sympathetic trunks. (2) Inhibitory cen- 

 ters lie in the upper part of the cord and the paths traverse the sympathetic 

 and splanchnics (according to Langley also the vagus). 1 



c. The Pylorus and Pyloric Antrum: (1) Contraction centers are found in 

 the corpora quadrigemina for both the pylorus and its antrum. The chief path 

 is the vagus, but the constrictor fibers run also through the spinal cord. (2) The 

 dilator center for the cardia gives inhibition of the pylori c movements, but no 



1 Cannon has shown that distress inhibits gastric movements not only in the normal 

 animal, but after the two vagi are cut, and after the four splanchnics are cut. ED. 



