The digestive process begins as soon as food is seen or smelled, causing the brain to trigger saliva production in the salivary glands. As food enters the mouth, it mixes with saliva containing the enzyme amylase. Chewing tears moistened food into smaller, easily digestible pieces, while amylase helps to break down carbohydrates into simpler sugars.Continue Reading
Throughout the alimentary canal, or digestive tract, organ and muscle activity is automatically stimulated by the presence of food matter. When a person swallows, food travels down the pharynx, or throat, and passes into the esophagus. The muscular lining of the esophageal tube repeatedly contracts in a wavelike motion, known as peristalsis, pushing food further down the digestive tract. A ring of muscle, known as a sphincter, closes off the esophagus from the stomach and opens reflexively when food is ready to exit.
The stomach produces acid and digestive enzymes that mix with partially digested food. Stomach muscles use peristalsis to churn the food and acid mixture until it becomes a thick, liquefied substance known as chyme. Chyme enters the small intestine, where food is absorbed through thin microscopic projections, or villi, located on extensive folds of the intestine
The pancreas, liver and gallbladder release digestive enzymes and bile into the small intestine through interconnected ducts. The remaining undigested food travels through another sphincter into the large intestine, which removes water from waste and prepares it for excretion.Learn more about Glands & Hormones