GASTRIC JUICE AND MECHANISM OF ITS SECRETION::
Gastric juice : The glands in the mucus coat of the stomach secrete gastric juice this is a clear and colourless fluid containing 0.4% hydrochloric acid gastric juice contains enzyme pepsin gastric renin and gastric lipase The pH of gastric juice is 0.9-1.5 i.e it is a highly acidic juice
Mechanisms of gastric secretion::
Body and fundus of the stomach secrete an acidic juice while the pyloric part secretes an alkaline juice normally fasting stomach secretes 10-60 ml of gastric juice per hour while 500 ml of gastric juice is secreted after meals The mechanism of gastric juice secretion has been studied in animals Two types of experiments have been described here
Sham Feeding Experiment ::
A small incision is made in the oesophagus of the dog and a glass tube is inserted directly into the stomach so as to collect the gastric juice when the dog swallows food it comes out through the oesophagus it does not enter the stomach still there is secretion of the gastric juice this experiment shows that gastric acid can be secreted by just the food in mouth (cephalic phase)
pavlovs pouch::
A small diverticulum representing about one eighth of the whole stomach is separated from the main body the open end of the pouch is brought upto the surface of the body and the inner end is shut off from the main cavity of the stomach this gives pure gastric juice devoid of food while the digestive processes are proceeding in the main stomach the diverticulum represents pari pasu the original inside stomach and thus facilitates the study of the mechanism of gastric secretion
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