GASTRIC GLANDS 



371 



neck of the glonct 



.HCl-Secretiiag 

 cell on inner* 

 imcrrgin of gland 



t*a>v 



■materials 



am, 



passage of food from the stomach. There is also another ring 

 of muscle guarding the entrance to the stomach. 



Gastric glands. The folded wall of the stomach is dotted with 

 thousands of tiny pits, the mouths of the gastric glands. The 

 gastric glands are little . 1 



tubes, the lining of m SL §J tfLnSSfa* 



which secretes the 

 gastric juice. When 

 we see or even think of 

 appetizing food, this 

 secretion is given out 

 in considerable quan- 

 tity. Just as the 

 mouth " waters " at 

 the sight or thought 

 of certain well-liked ^fj 5 * 

 foods, the gastric by the 

 glands of the stomach 5 t r<2 ; 

 also pour out their 

 secretions under simi- 

 lar stimuli. Gastric 

 juice is slightly acid 

 in its chemical reac- 

 tion, containing about j 

 0.2 per cent free 

 hydrochloric acid. It 

 also contains two 

 enzymes : one very 

 important, called 

 pepsin, and the other, less important, called rennin. Rennin 

 curdles or coagulates a protein found in milk; after the milk is 

 curdled, the pepsin is able to act upon it. " Junket " tablets, 

 which contain rennin, are used sometimes in the preparation of a 

 dessert from milk. 



Action of gastric juice. If proteins are treated with artificial 

 gastric juice at the temperature of the body, they will become 

 swollen and then gradually change to substances (peptones) which 



..cell secreting* 

 f luridC Containing 



C-hody of the gland 



*vhere most of the 



secreting is done 



Gastric glands secrete a substance which is changed into 

 pepsin in the presence of acid. The secretion of these glands 

 forms the gastric fluid. 



