軍人&預官◆英文題庫下載題庫

Questions 37-40

        The process of digestion in the human body begins even before food enters the mouth. When your eyes see food, your nose smells food, or your brain thinks about food, the mouth begins to produce saliva, or juices of the mouth, which helps to start the process of breaking down food. After you put food in your mouth, you chew it. When food is small enough to be swallowed, it travels down through the esophagus, a long, stretchy pipe about 10 inches long. Its job is to move the food from the mouth to the stomach.

         The stomach, an organ shaped like the letter “J”, is the next stop along the route. It has three main jobs: (a) to store food, (b) to further break down food with digestive juices and turn it into liquid, and (c) to empty the liquid into the small intestine. Once the liquid mixture produced by the stomach reaches the small intestine, the mixture is broken down even more so that the body can absorb all the vitamins and other nutrients it contains. Slowly the mixture passes through all 22 feet of the intestinal tract before reaching the large intestine. Overall, it takes approximately 24 to 72 hours for the human body to digest food.