Chapter 4 – Digestion, Absorption, and Transport: How the body uses food

The breakdown of complex macromolecules in foods to absorbable components is accomplished by the digestive system. These components are processed by cells throughout the body into energy or are used as building blocks. The digestive system is composed of the mouth, pharynx, esophagus, stomach, small intestine, large intestine (or colon), rectum, and anus. There are four steps in the digestion process: ingestion, the breakdown of food, nutrient absorption, and elimination of indigestible food.