The stomach initiates the digestion of food, but it doesn't fully break down all food components into their smallest units. The main products of stomach digestion are partially digested proteins and a semi-liquid mixture called chyme.
Stomach Digestion: A Closer Look
The stomach's primary role in digestion involves breaking down proteins. This process begins with the action of hydrochloric acid (HCl) and the enzyme pepsin. HCl creates an acidic environment that unfolds protein molecules, making them more accessible to pepsin. Pepsin then begins the process of breaking proteins down into smaller polypeptide chains (smaller units of proteins). While some carbohydrate and fat digestion can begin in the mouth, the stomach's acidic environment inhibits further carbohydrate and fat breakdown.
- Partial Protein Breakdown: Proteins are not fully digested in the stomach; instead, they are broken down into smaller peptides.
- Chyme Formation: The stomach churns and mixes the food with digestive juices, forming a semi-liquid mixture called chyme. Chyme then moves into the small intestine for further digestion and absorption.
- Limited Fat and Carbohydrate Digestion: While minimal fat and carbohydrate digestion may begin in the mouth, the stomach's acidic environment halts significant digestion of these macromolecules until they reach the small intestine.
The final products of digestion (monosaccharides, amino acids, fatty acids, and glycerol) are primarily produced and absorbed in the small intestine, not the stomach. Therefore, focusing solely on the stomach, the key products are partially digested proteins and chyme.
