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How does the human digestive system break down food into nutrients?

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Diagram of the human digestive system viewed from the front, showing and labeling organs including the mouth, teeth, tongue, salivary glands, pharynx, esophagus, liver, stomach, gallbladder, pancreas, large intestine, small intestine, appendix, rectum, and anus. — human digestive system The human digestive system as seen from the front.

The human digestive system breaks down food through a combination of mechanical and chemical processes. Digestion begins in the mouth, where teeth chew food and saliva starts to break down carbohydrates. The food then travels down the esophagus to the stomach, where gastric juices containing enzymes like pepsin and hydrochloric acid further break down proteins and fats, forming a semiliquid substance called chyme.123

The small intestine is where most nutrient absorption occurs. Here, enzymes from the pancreas and bile from the liver continue to break down carbohydrates, proteins, and fats into absorbable nutrients. These nutrients are then absorbed into the bloodstream. Finally, undigested material moves to the large intestine, where water and salts are absorbed before waste is eliminated.41