PHYSIOLOGICAL ANATOMY OF THE STOMACH. 



215 



glands secrete pepsine but no acid. According to the views just stated, in 

 the glands of the greater pouch, the acid is secreted by the rounded acid-cells 

 while the pepsine is secreted by cells (peptic cells) similar to those which line 

 the secreting portion of the pyloric glands. During the intervals of diges- 

 tion, pepsine is in process of formation by the peptic cells, and no acid is 

 produced ; but acid begins to be secreted soon after food is received into the 

 stomach. It is now thought that the peptic cells do not produce pepsine 

 directly, but a substance sometimes called zymogen, but more properly pro- 

 pepsine or pepsinogen, which is changed into true pepsine by the action of 

 hydrochloric acid. 



There is some confusion among writers with regard to the names of the 

 different kinds of secreting cells of the stomach, the acid -cells being fre- 

 quently described as " peptic cells." It seems proper, however, to call the 



FIG. 61. Glands of the greater pouch of 

 the stomach (Heidenhain). 



FIG. 62. Pyloric glands (Ebstein). 



cells which produce pepsine, peptic cells, and the cells that are supposed to 

 produce acid, acid-cells. 



The glands of the stomach have an excretory portion and a secreting 

 portion, the latter presenting several branches. The excretory portion is 

 lined by cells like those found on the surface of the mucous membrane. 



