1. Chapter 18.2a
The Digestive System

2. Functions of the Digestive System
There are 4 stages of processing food: ingestion, digestion, absorption, and elimination.
Digestion is the process that breaks down food into small molecules so they can be absorbed and moved into the blood. This is important because food molecules are transported across the cell membrane to be used by the cell.
Mechanical digestion takes place when food is chewed, mixed, and churned.
Chemical digestion is when chemical reactions occur that break down large molecules of food into smaller ones.

3. Enzymes
An enzyme is a type of protein that speeds up the rate of a chemical reaction in your body.
Enzymes reduce the amount of energy needed for a chemical reaction to begin.

4. Enzymes in Digestion
Enzymes help you digest carbs, proteins, and fats.
Amylase is an enzyme produced in the mouth and helps breakdown complex carbs into simple carbs.
In your stomach you have the enzyme pepsin to help break down complex proteins.
There are many enzymes in your small intestines to continue the break down process.
The pancreas releases enzymes into the small intestine to break down starch.

5. Other Enzyme Actions
Enzymes don’t just work in digestion. There are enzymes that help chemical reactions to build your body.
Enzymes also aid in the blood-clotting.
You would not exist without enzymes.