Background Information

Digestion: Includes both the physical and chemical processes that reduce food to small soluble molecules that can be absorbed.

Absorption: The entrance of these molecules across the gut lining (especially across microvilli which are the tiny finger-like projections of the small intestine).

- Only certain substances can be absorbed
a. Amino acids of proteins
b. Sugars of carbohydrates
c. Glycerol and fatty acids of fats
d. Some minerals and water

Elimination (defecation): All components except those mentioned above exit the body.

Chemical Digestion: Chemical breakdown of food

- enzymes are used

Physical Digestion: - Physical breakdown of good

- Increases surface area so enzymes can work on them

For review ....

The process of digestion begins as soon as food—let’s say, a muffin—enters the mouth. Chewing breaks down the food into pieces small enough to swallow, and the mouth begins to water.