The Digestive Process

The Digestive Process

The process of digestion starts when food enters the body through the mouth where it is chewed, broken into small pieces, and mixed with saliva. The fluid secreted by the salivary glands contains digestive enzymes that act upon carbohydrates. From the mouth, food passes to the stomach by way of the esophagus.

The digestion of certain foods continues in the stomach under the influence of the secretions and churning action of the stomach wall. Ordinarily, a mixed meal leaves the stomach in three to four hours. Carbohydrates leave the stomach most rapidly, followed by protein. Fats remain in the stomach for a longer period.

Thus, the sensation of hunger will occur sooner after a meal that is high in carbohydrate than after a meal containing adequate amounts of proteins or fat.

Beyond the Stomach

After leaving the stomach, the liquefied mass, called chyme, passes into the small intestine for further absorption into the body. The small intestine is affected by secretion from its walls and from the liver and pancreas. The undigested food residues pass from the small intestine to the large intestine or colon. This material also contains some of the end products of digestion such as water, as well as waste materials. These waste products travel through the large intestine where they await periodic excretion from the body.