§4.111 DIGESTIVE GLANDS 121 



Stomach, chiefly in the pyloric region, and stimulates the exocrine 

 glands of the mucosa in the fundus to secrete HCl into the lumen 

 of the stomach. There is some evidence that as acid increases in 

 the stomach the secretion of gastrin is inhibited. Nerves of the 



I n 



(a) (b) 



Fig, 4-2. Diagrams showing the two operative stages by which 

 a pouch from the fundus of the stomach of a dog, Cams, is isolated 

 from the rest of the gut and grafted into the mammary gland, 

 where it acquires a new blood supply (I, 116 and IIIc), and an 

 opening to the exterior at 4. The remaining pyloric part of the 

 stomach is stitched up and later brought to the exterior by an open- 

 ing at 9, 10. (I, lla and lllb). The oesophagus at 5, 6 is joined to 

 the duodenum at 13, 14, so that food by-passes the stomach (Ila 

 and Ilia). This arrangement was used to demonstrate the presence 

 and action of gastrin (from Grossman, Robertson and Ivy, 1948). 



vagus can also stimulate the flow^ of gastric secretion ; but it seems 

 clear from experiments like the above that they are not necessary 

 for the release of either gastrin or of acid. How far they may in- 

 crease the natural secretion of the juices and their enzyme content 

 is not clear. 



