the digestive system
The digestive system helps us break down the food we eat both mechanically and chemically into smaller compounds that can then be utilized for energy. Digestion is a form of catabolism, because it breaks down larger foods into smaller particles that can be absorbed into the bloodstream. The digestive system helps us digest the food we eat and absorb the nutrients that we need to survive. The food enters the mouth, and is chewed and broken down mechanically by the teeth and chemically by saliva in the mouth. It then moves into the esophagus, and it is massaged into the stomach, where it is chemically digested by hydrochloric acid and massaged to aid in digestion. It then moves to the small intestine, where all of the nutrients needed are absorbed out of the food. The large intestine is responsible for taking the correct amount of water out of the nutrients, so that it can be excreted.