1. The Digestive System

2. The Digestive System The digestive system has three main functions:
It breaks down food into particles that the body can use.
It absorbs nutrients into the blood.
It eliminates waste from the body.
Mouth
Esophagus

3. The Digestive System
Digestion can happen in two ways:
Mechanical digestion: foods are physically broken down into smaller parts (like by teeth).
Chemical digestion: Chemicals break foods into their smaller “building blocks” (for example, starch gets broken down into sugar).
Mouth
Esophagus

4. The Digestive System
In the mouth, your teeth break down food into smaller pieces (mechanical digestion). Saliva has enzymes that start chemical digestion.
The smooth muscles in the esophagus push food down to the stomach (peristalsis).
Mouth
Esophagus

5. The Digestive System Most digestion happens in the stomach:
Mechanical digestion occurs when the stomach muscles churn the food.
Chemical digestion happens when stomach acid breaks down food.
Mouth
Esophagus
Stomach

6. The Digestive System
The liver, gallbladder and pancreas produces & stores chemicals that help digest food in the small intestine.
Mouth
Esophagus
Stomach
Liver
Pancreas
Gallbladder

7. The Digestive System
The small intestine absorbs nutrients for the body. The nutrients pass through the villi into blood vessels.
In the large intestine, water is reabsorbed by the body.
The rectum compresses the waste into a solid form.
Mouth
Esophagus
Stomach
Liver
Pancreas
Gallbladder
Small intestine
Large intestine
Rectum