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digestion
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Images & Videos
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.
The chemistry of digestion: How food is broken down
Why do people feel full after a big meal?
Digestive vacuole
Why can coffee act as a laxative?
Why does your stomach make noise?
The small and large intestines animated
Major organs of the human digestive system. Food taken in by the mouth is guided by the tongue as it is sheared and ground by the teeth. The bolus of chewed food is moistened and lubricated with saliva secreted by the salivary glands. Enzymes in the saliva begin the breakdown of starches. The epiglottis, a flap of tissue, prevents food from the pharynx from entering the larynx during swallowing. Muscles in the esophagus wall contract in waves to move the food to the stomach. Gastric juices secreted by the stomach contain a mixture of substances (including enzymes and hydrochloric acid) that break down the food into a semiliquid mass called chyme. The chyme passes into the small intestine, where food molecules are broken down into sugars, amino acids, and fatty acids. These useful substances are absorbed into the bloodstream as the food passes through the duodenum, jejunum, and ileum. The pancreas secretes digestive enzymes into the duodenum. The liver secretes bile salts that make insoluble fats entering the small intestine water-soluble and vulnerable to enzymatic action. Excess bile salts are stored in the gallbladder. The large intestine (colon) serves to remove water and electrolytes from the digested chyme and to compact and store undigestible material, called feces. Fecal matter is moved by muscular contractions into the rectum and expelled from the anus.
At a Glance
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digestion summary
Quizzes
Male muscle, man flexing arm, bicep curl.
Facts You Should Know: The Human Body Quiz
greylag. Flock of Greylag geese during their winter migration at Bosque del Apache National Refugee, New Mexico. greylag goose (Anser anser)
Biology Bonanza
Muscles of facial expression, human anatomy, (Netter replacement project - SSC). Human face, human head.
Characteristics of the Human Body
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digestion: References & Edit History

Article Contributors

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  • The Editors of Encyclopaedia Britannica
    Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.

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Article History

Type Description Contributor Date
Modified link of Web site: National Center For Biotechnological Information - Physiology, Digestion. Nov 01, 2026
Add new Web site: OpenStax - Biology 2e - Digestive System Processes. Sep 02, 2026
Add new Web site: Johns Hopkins Medicine - The Digestive Process: What Is the Role of Your Pancreas in Digestion? Jun 26, 2026
Add new Web site: OpenStax - Nutrition for Nurses - Digestion. Feb 21, 2026
Add new Web site: NC State University Libraries - Introductory Biology: Ecology, Evolution, and Biodiversity - Digestion. Apr 12, 2025
Article restructured and cross-references added. Feb 18, 2025
Add new Web site: NHS - Good foods to help your digestion. Dec 03, 2024
Add new Web site: Al-Mustaqbal University - Digestion physiology. Oct 08, 2024
Add new Web site: Khan Academy - Digesting Food. Jan 26, 2024
Add new Web site: CalState-Pressbooks Network - Nutrition and Physical Fitness - Digestion and Absorption. Nov 28, 2023
Add new Web site: BBC Bitesize - Digestion. Aug 25, 2023
Add new Web site: Biology LibreTexts - Digestion and Absorption. Dec 16, 2022
Add new Web site: National Center For Biotechnological Information - Physiology, Digestion. Sep 28, 2022
Media added. Apr 08, 2016
Add new Web site: MedicineNet - The Digestion Process. Feb 24, 2016
Add new Web site: Mayo Clinic - See How Your Digestive System Works. Feb 24, 2016
Article revised. Jul 15, 2005
Article added to new online database. Jul 20, 1998
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