1. Digestion is the breakdown of food into simpler molecules that can be absorbed by the body.
2. The digestion system is actually a long, hollow tube called the gastrointestinal tract or GI tract.
3. The digestion system includes the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
4. Several major glands, including the salivary glands, the pancreas, and the liver, add their secretions to the digestion system.
5. Three activities are involved in the digestive process: mechanical digestion, chemical digestion, and absorption.
6. The first step of the digestion system is to break down food into a fine pulp (mechanical), to increase it's surface area and expose more food molecules to the actions of digestive chemicals.
7. The process of mechanical digestion breaks food into tiny pieces without changing the chemical structure of the food.
8. The second task of the digestion system is to chemically act on food, breaking it down into smaller and smaller particles. The molecules must be small enough and chemically simple enough to be absorbed into the bloodstream. Examples: starches to simple sugars, proteins to amino acids.
9. The last task of the digestion system is to absorb the small molecules and pass them to the bloodstream for distribution to the rest of the body.
10. Humans are omnivores who eat both plants and animals for energy and our digestive system is adapted to process both vegetable and animal materials.

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