digestion
Major organs of the human digestive system. Food taken in by the mouth is guided by the tongue as …
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Process of dissolving and chemically converting food for absorption by cells. In the mouth, food is chewed, mixed with
saliva, which begins to break down starches, and kneaded by the tongue into a ball for swallowing.
Peristalsis propels it through the esophagus and the rest of the alimentary canal. In the stomach, food mixes with
acid and
enzymes, which further break it down. The mixture, called
chyme, enters the duodenum, the first part of the small intestine.
Bile from the liver breaks up
fat globules. Enzymes from the pancreas and intestinal glands act on specific molecules, breaking
carbohydrates down into simple
sugars,
proteins into
amino acids, and fats into
glycerol and
fatty acids. These products are absorbed by the bloodstream. Indigestible substances, such as
fibre, pass into the large intestine, where water and
ions are reabsorbed and
feces held for
excretion.
digestion1. the act or process in living organisms of breaking down ingested food material into easily absorbed and assimilated substances by the action of enzymes and other agents
2. mental assimilation, esp of ideas
3. Chem the treatment of material with heat, solvents, chemicals, etc., to cause softening or decomposition
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