The digestive system is one of many systems in the human body. It functions to break down food we eat into energy our cells can use. Your digestive system includes your mouth, esophagus, stomach, small and large intestine and food travels through your digestive system in that order. The food enters your mouth where saliva and your teeth begin to break it down. As you swallow food travels down your esophagus with the help of muscle contractions called peristalsis and into your stomach where stomach acid and churning break down the food even more. Food then enters the small intestine where it is broken down more with the help of secretions from other organs and nutrients such as carbohydrates, lipids and proteins are absorbed. The large intestine absorbs any leftover nutrients and water before the waste is excreted from your body.