What Organ Is the First Major Site of Chemical Digestion?

Our moms were right; we need to chew.

The digestive tract ends at the anus, but it begins in the mouth. Here is where food begins both its chemical processing for digestion, and also, its physical processing (chewing).

Amylase

The amylase digestive enzyme (also called diastase) is found in saliva, and begins the process of breaking down starches and sugars (the carbohydrates) in food before you swallow it.

Chewing

Chewing, or mastication, is a physical act; but more chewing exposes more starch and sugar to digestive enzymes, preparing them for the rest of the digestive tract. It also reduces the proteins in meats for more efficient chemical digestion.

Stomach

If a person chews well enough, then, the digestive enzymes and acids in the stomach can better attack and break down the food for further absorption. The stomach produces about 3 quarts of acids and enzymes each day.

Absorption

As crucial as the mouth and stomach are in digestion, it is in the colon that nutrients (like vitamins) are absorbed into the blood stream. Thus, oral digestion affects stomach digestion, then, absorption in the colon of nutrients.

The Nose

Technically, chemical digestion begins when we smell food.

The nose may not seem like part of the digestive tract, but smells trigger the production of saliva and amylase in the mouth; so it could be considered the first organ of chemical digestion.

References

• Natural Digestive Diseases Information Clearinghouse: Your DIgestive System and How It Works
• "Enzymes and Their Applications"; Jean Effront; 2009
• KidsHealth: How Digestion Works