Four Main Function of the Digestive System


Motility: Mechanical breakdown and mixing of ingested nutrients by smooth muscle movements, passage of nutrients through the digestive tract, and elimination of undigested or unabsorbed residues from the body.

Secretion: Release of enzymes, hormones, and other substances that take part in digestion.

Digestion: Chemical reduction of ingested nutrients into particles, then into molecules small enough to cross the lining of the gut and reach the internal environment of the body.

Absorption: Passage of digested nutrients from the gut lumen into the blood or lymph, which distributes them throughout the body.

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