what happens in the stomach at a molecular level?
the acid breaks down proteins.
At a molecular level, there are several important processes that occur in the stomach. Here's an explanation of what happens:
1. Gastric Secretion: The stomach lining contains specialized cells known as gastric glands. These glands secrete various substances that aid in digestion. The main secretions include hydrochloric acid (HCl), mucus, and digestive enzymes such as pepsinogen.
2. Acid Secretion: One of the important functions of the stomach is to produce hydrochloric acid. This highly acidic environment, with a pH between 1.5 and 3.5, helps in the breakdown of food and kills harmful microorganisms.
3. Protein Digestion: Pepsinogen, a precursor enzyme, is secreted by the gastric glands. In the presence of hydrochloric acid, pepsinogen is converted into its active form called pepsin. Pepsin is responsible for breaking down proteins into smaller peptide fragments during the process of proteolysis.
4. Mixing and Churning: The stomach muscles contract in a coordinated manner, which helps to mix food with gastric secretions. This churning action, along with the presence of mucus, breaks down food into smaller particles, forming a semi-fluid mixture called chyme.
5. Partial Carbohydrate Digestion: While protein digestion primarily occurs in the stomach, partial carbohydrate digestion also takes place. Salivary amylase, present in the food that enters the stomach, continues to break down carbohydrates into smaller sugars until it gets deactivated by the acidic environment.
It's important to note that these processes represent a simplified explanation of what happens in the stomach at a molecular level. The stomach's role is crucial in the digestion and breakdown of food before it moves on to the small intestine for further processing.