This is not the same hormone as the renin from the kidneys. Pepsinogen is converted to the active protein digesting form, pepsin. This conversion is aided by the low pH of 1-3, which is due to the HCl secreted by specific stomach mucosal cells. Food and liquid are mixed with stomach secretions to form acidic chyme . Chyme is squirted into the duodenum of the small intestine through the pyloric sphincter .
Some absorption occurs in the stomach.
The stomach absorbs relatively few substances and these are absorbed in small amounts. Some of the substances absorbed are caffeine aspirin alcohol Table 47.3 provides a summary of the enzymes, site of production, action, and site of action for stomach enzymes and other enzymes. The total length is just over 6 m. At the other end of the small intestine is the ileocecal valve . This is found at the point where the ileum meets the cecum of the colon.