What happens to the food in stomach?

In the stomach, food undergoes mechanical and chemical digestion. Here's a detailed breakdown of what happens to food in the stomach:

1. Mechanical Digestion:

- The stomach muscles contract and relax, physically churning and mixing the food. This muscular action breaks down the food into smaller pieces, increasing the surface area for better enzyme action.

2. Chemical Digestion:

- The primary chemical digestion in the stomach involves the enzyme pepsin, which is secreted by the chief cells in the stomach lining. Pepsin is activated by the acidic environment created by hydrochloric acid (HCl) also produced by the stomach.

- HCl: Hydrochloric acid creates an acidic environment with a pH of about 1 to 2. This acidic environment is necessary for the activation of pepsin and also acts as a barrier against harmful bacteria.

- Pepsin: Pepsin is a protease enzyme that breaks down proteins into smaller polypeptide chains. It works best in an acidic environment. Pepsin begins the process of protein digestion, breaking down complex proteins into simpler molecules.

3. Chyme Formation:

- As mechanical and chemical digestion occur, the food mixture in the stomach is transformed into a semi-liquid substance called chyme.

- Chyme consists of partially digested food particles, gastric juices (including pepsin and HCl), and mucus produced by the stomach lining.

4. Gastric Emptying:

- Once the chyme reaches a certain consistency and acidity, it is released from the stomach and enters the small intestine through the pyloric sphincter, a muscular valve at the lower end of the stomach.

- The rate of gastric emptying is regulated by various factors, including the type of food consumed, its nutritional content, and hormonal signals.

The stomach plays a crucial role in the initial digestion of food, breaking down proteins and preparing the food for further digestion and absorption in the small intestine.