Trávenie

Trávenie is the biological process by which food is broken down into smaller molecules that can be absorbed and used by the body. It combines mechanical processes, such as chewing and stomach churning, with chemical processes driven by enzymes, acids, and bile. The digestive system consists of the alimentary canal and accessory organs, including the mouth, esophagus, stomach, small intestine, and large intestine, as well as the liver, pancreas, and gallbladder.

In the mouth, mechanical digestion and salivary amylase begin the breakdown of starch. The stomach uses acid, mainly hydrochloric acid, and enzymes such as pepsin to initiate protein digestion and to churn food into a semi-liquid substance called chyme. The small intestine is the principal site of digestion and absorption. Pancreatic enzymes (lipase, amylase, proteases) and bile from the liver and gallbladder aid digestion, while brush-border enzymes complete nutrient breakdown. Most nutrient absorption occurs in the small intestine, especially in the jejunum and ileum, through the finger-like villi and microvilli.

Absorbed nutrients enter the bloodstream or lymphatic system. Carbohydrates are broken down to monosaccharides, proteins to amino acids, and fats to fatty acids and monoglycerides. Water, vitamins, minerals, and other small molecules are absorbed along the tract, with the large intestine reclaiming water and electrolytes. The gut microbiota in the colon ferments undigested substrates, producing short-chain fatty acids and gases.

Regulation of trávenie involves the enteric nervous system and hormones such as gastrin, secretin, and cholecystokinin, which influence secretion and motility. Disturbances can indicate disorders such as dyspepsia, gastritis, malabsorption, or inflammatory bowel disease.