Accessory organs and glands produce various secretions that aid the digestive processes. Figure 47.13 illustrates the organs of the human gut as well as the accessory organs and glands. Learn these organs and glands. Figure 47.10 illustrates the layers of the vertebrate gut. Learn these various layers and the association of the pancreas and its duct with the gut.
Digestion begins in the mouth where salivary amylase starts the breakdown of carbohydrates.
Some digestion as well as absorption occurs in the stomach. Protein digestion begins in the stomach. 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 .