1. The Digestive System

2. The Digestive System The digestive system has 3 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 called ENZYMES break foods into their smaller “building blocks” (for example, starch gets broken down into sugar).
Mouth
Esophagus

4. The Digestive System
MOUTH: your teeth break down food into smaller pieces (mechanical digestion). Saliva has enzymes that start chemical digestion.
ESOPHAGUS: smooth muscles 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
Liver, gallbladder and pancreas: produces & stores chemicals (enzymes) that help digest food in the small intestine.
Mouth
Esophagus
Stomach
Liver
Pancreas
Gallbladder

7. The Digestive System
Small intestine: completes chemical digestion and absorbs nutrients for the body. The nutrients pass through the villi into blood vessels.
Large intestine: water is reabsorbed by the body.
Rectum: compresses waste into a solid form.
Mouth
Esophagus
Stomach
Liver
Pancreas
Gallbladder
Small intestine
Large intestine
Rectum