The Human Digestive System

The Human Digestive System

Digestion breaks down large food molecules into smaller, soluble ones that can be absorbed into the bloodstream. It happens through both mechanical breakdown (chewing) and chemical breakdown (enzymes).

The journey of food

Food travels from the mouth (chewing, saliva) to the stomach (acid and enzymes break down protein) to the small intestine (most digestion and absorption happens here) to the large intestine (water is absorbed from waste).

Enzymes

Enzymes are biological catalysts that speed up digestion. Amylase breaks down starch, protease breaks down protein, and lipase breaks down fats.

Practice

Which organ absorbs most of the digested nutrients into the blood?