How does the body regulate the acidity of gastric juice?

• A. By secreting enzymes only
• B. Through the secretion of bicarbonate and controlling gastric acid production
• C. By increasing bile flow
• D. With the help of the kidneys

Answer: (B)

The body regulates the acidity of gastric juice primarily through the secretion of bicarbonate and controlling gastric acid production. Gastric juice is composed mainly of hydrochloric acid, which is secreted by parietal cells in the stomach lining. This acid is crucial for digestion and helps maintain a low pH necessary for enzyme action.

When the stomach produces acid, the body must also balance this acidity to protect the stomach lining and ensure that the pH inside the stomach remains optimal for digestion. The pancreas plays a key role by secreting bicarbonate into the small intestine, which helps neutralize any excess gastric acid that has passed into the intestine. Furthermore, the regulation of gastric acid production is influenced by various hormones and nerve impulses, which can increase or decrease acid secretion based on the body's needs, such as the presence of food.

In contrast, while enzymes are important for digestion, they do not directly regulate acidity. Increasing bile flow relates more to fat digestion and does not address the regulation of gastric acidity. The kidneys help maintain overall acid-base balance in the body by regulating bicarbonate and hydrogen ions, but their role is focused on the systemic level rather than specifically on gastric juice acidity. Thus, the combination of bicarbonate secretion and gastric acid production control makes the