Understanding Digestion
Most people forget that digestion begins with sight, smell, touch, or sound. We see food that we love and the gastric juices begin making our stomach growl.
Once the food has found its way to your mouth, the process of digestion continues. The tongue and teeth are involved, as well as saliva. The teeth chew and grind the food, mixing it with saliva, as the tongue moves it to the back of the mouth. Some of this process is voluntary. You are actively involved, while the autonomic nervous system covers the involuntary stages.
Moving the Food
As you begin to swallow, the food moves from the mouth to a structure called the pharynx and from the pharynx into the esophagus. This process is controlled by the nervous system, as breathing stops to allow swallowing, preventing food from entering into the respiratory tract. As the food moves into the esophagus, breathing resumes.
The involuntary muscles in the esophagus contract, moving the food down the column into the stomach. A sphincter at the entrance of the stomach prevents food from backing up into the esophagus. Once in the stomach, hydrochloric acid and the enzyme pepsin process the food and move it on to the duodenum, through the pyloric sphincter.
Fact
The smell emanating from the cooking of apple pie, lasagna, turkey, or whatever the favorite that was cooked in your home, triggers a response in the brain. The sound, sight, smell, even the touch of food being prepared stimulates stored memories. The impulses sent by the brain activate the salivary glands, implementing digestion.
Pancreas, Liver, and Gallbladder
The pancreas is instrumental in digestion, as it produces enzymes that digest carbohydrates, fats, and proteins. The liver produces bile, a compound that breaks down and absorbs fats and processes cholesterol. The gallbladder stores bile until the small intestine needs it for digestion. All three of these organs unite at a common duct to empty into the duodenum.
The Duodenum
This small structure holds a great deal of power. This tiny segment of the small intestine begins at the pyloric sphincter of the stomach and moves out to another portion of the small intestine. Most of the digestion takes place in the twelve inches of the duodenum.
Almost every organ of the digestive system seems to have a connection with this small curve of the intestines. Some of the digested food from the stomach comes into the duodenum. The pancreas sends enzymes while the liver sends bile. The main process of digestion has been completed in this section. The remainder of the work to be done is absorption and elimination, which is performed by the rest of the intestines and the colon.
