The Human Digestive System: How the Body Breaks Down Food and Absorbs Nutrients
Every meal begins an extraordinary biological journey. The food we eat contains carbohydrates, proteins, fats, vitamins, minerals and water, but most nutrients cannot simply move from a meal directly into the body's cells. Food must first be mechanically and chemically processed into forms that can be absorbed and used. This is the work of the digestive system. Understanding digestion connects human biology, chemistry, biochemistry, nutrition, microbiology and medicine. What Is the Digestive System? The digestive system consists of the gastrointestinal tract together with accessory organs that contribute to digestion. The gastrointestinal tract includes: Mouth Pharynx Esophagus Stomach Small intestine Large intestine Rectum Anus Important accessory organs include the salivary glands, liver, gallbladder and pancreas. Together, these structures break food down, absorb nutrients and water, and eliminate material that the body cannot digest or use. Digestion Begins in the Mouth Digesti...