1. movement: propels food through the digestive system
2. secretion: release of digestive juices in response to a specific stimulus
3. digestion: breakdown of food into molecular components small enough to cross the plasma membrane
4. absorption: passage of the molecules into the body's interior and their passage throughout the body
5. elimination: removal of undigested food and wastes

Three phases occur during what we loosely refer to as "digestion". Digestion proper, which is the mechanical and chemical breakdown of food into particles/molecules small enough to pass into the blood stream. Absorption into the blood stream. Assimilation, the passage of the food molecules into body cells.

Information provided by: http://gened.emc.maricopa.edu