Meat and vegetables supply vital nutrients, such as proteins, fats and starches. The problem is, however, that your body only assimilates small food molecules, whereas protein, fat and starch molecules are quite large. Digestion, therefore, chops these long chemical chains down to size. From the moment you see, smell or even think about a tasty food item, your body prepares itself for digestion. Imagine, for example, that you have before your eyes a piece of juicy, boneless breast of chicken, nestled between two fresh slices of whole-wheat bread. Just the sight of it starts your mouth watering, doesn’t it? Secretly, your stomach starts secreting digestive fluids. Now take a healthy bite of this luscious treat and your body’s digestive system swings into full gear. Your mouth warms (or cools) the food to the right temperature. Chewing not only lets you savor the food but also grinds it to an easily swallowed pulp. Salivary glands help by pumping out saliva to moisten and soften the food. Enzymes in the saliva go to work on the bread, transforming starches into simple sugars. From the mouth, your meal must now journey to its next stop—the stomach. There the chicken can be
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This note was uploaded on 02/15/2010 for the course SCIENCE 241 taught by Professor Staff during the Summer '09 term at Arizona.