STRUCTURE OF THE PANCREAS. 



337 



The air in the stomach is constantly undergoing changes, whereby 

 its O is absorbed by the blood, and for 1 vol. of absorbed 2 vols. of 

 C0 2 are returned to the stomach from the blood. Hence, the amount 

 of in the stomach is very small, the CO., very considerable (Planer). 



Gases in the Stomach Vol. per cent. (Planer). 



A part of the C0 2 is set free by the acid of the stomach from the 

 saliva, which contains much CO., (p. 292). The N acts as an in- 

 different substance. 



Abnormal development Of gases in persons suffering from gastric catarrh, 

 only occurs when the gastric contents are neutral in reaction ; during the butyric 

 acid fermentation H and COa are formed, while the acetic-acid and lactic -acid 

 fermentations do not cause the formation of gases. Marsh gas (CH 4 ) has also 

 been found, but it must come from the intestine, as it can only be formed when no 

 O is present (Intestinal Oases). 



168. Structure of the Pancreas. 



The pancreas is built on the type of compound tubular or acino- 

 tubular glands, and in its general arrangement into lobes, lobules and 

 system of ducts and acini, it corresponds exactly 

 to the true salivary glands. The epithelium 

 lining the ducts is not at all, or only faintly, 

 striated. The acini are tubular or flask - 

 shaped, and often convoluted. They consist of 

 a membrana propria, resembling that of the 

 salivary-glands, lined by a single layer of some- 

 what cylindrical cells, with a more or less 

 conical apex towards the very narrow lumen of 

 the acini. [As in the salivary glands, there 

 is a narrow intermediary part of the ducts 

 opening into the acini, and lined by flattened 

 epithelium]. The cells lining the acini consist 

 of two zones (Fig. 139) : 



(1.) The smaller parietal layer (outer) is transparent, homogeneous, 

 sometimes faintly striated, and readily stained with carmine and log- 



22 



Fig. 139. 



Section of the tubes of 

 the pancreas in the 

 fresh condition. 



