92 



ADVANCED PHYSIOLOGY 



too, numbers of sac-like outgrowths from the stomach are 

 provided, in the cavities of which water is stored to be used 



when the animal 

 needs it. On the ex- 

 terior of the human 

 stomach 

 covering 



FIG. 49. THE STOMACH OF A SHEEP 



Showing the four compartments. (Huxley) 



is a moist 

 which is. 



in reality, continuous 

 with the mesentery 

 in which the intes- 

 tine is swung. Inside 

 this are three sets of muscle fibres, longitudinal, circular and 

 oblique, and separated from the lining of the 

 stomach by a thin layer of fat, the function of 

 which cannot be definitely stated. 



Next comes the stomach lining proper. If this is 

 seen when the stomach is empty, there appears to 

 be a series of wrinkles or folds, going lengthwise 

 of the organ, from the pyloric to the cardiac 

 regions; these folds are spoken of as rugae; 

 Fig. 48. Furthermore, if any part of the inner 

 wall, on or between the folds, were to be 

 examined with a lens, the appearance would be 

 that of innumerable tiny pits, of polygonal 

 shape, giving to the whole the semblance of an 

 extremely fine celled honey-comb. These pits 

 are scarcely over one one-hundredth of an inch 

 in diameter, and in the bottom of each is a 

 minute opening through which gastric glands 

 pour a secretion. The glands are short and 

 cylindrical, thousands in number, and can be 

 compared to tiny tubes lying side by side, with 

 their mouths opening into the stomach cavity; 

 Fig. 50. Each of these glands is lined with 

 large cells which make gastric juice from the 



FIG. 50. A 



SINGLE 

 GASTRIC 

 GLAND 

 Very highly 

 magnified 



