ATI Pathophysiology Practice Exam

Which substance is primarily involved in the destruction of ingested pathogens?

1. Stomach acid

2. Saliva

3. Pancreatic enzymes

4. Bile

The correct answer is: Stomach acid

Stomach acid plays a crucial role in the destruction of ingested pathogens. The acid environment in the stomach, primarily due to hydrochloric acid, creates a highly acidic pH that is hostile to many microorganisms, including bacteria and viruses. This acidic environment not only helps in the initial breakdown of food but also serves as a significant barrier against pathogens that are ingested through food and drink. The strong acidity denatures proteins and disrupts the cell walls of many pathogens, leading to their inactivation or destruction. While saliva contains enzymes and antimicrobial substances that can begin the process of digestion and help control pathogens in the mouth, it is not as effective as stomach acid for this purpose. Pancreatic enzymes and bile are essential for digestion in the small intestine, but they do not play a direct role in the destruction of pathogens. Pancreatic enzymes primarily digest carbohydrates, proteins, and fats, while bile aids in emulsifying fats and does not have a significant antimicrobial effect. Therefore, the primary substance involved in the immediate destruction of ingested pathogens, making it the most significant defense mechanism during digestion, is stomach acid.