What is the role of the small intestine’s MALT?
A. secreting mucus
B. buffering acidic chyme
C. activating pepsin
D. preventing bacteria from entering the bloodstream
b) buffering acidic chyme
- Correct: MALT (Mucosa-Associated Lymphoid Tissue) in the small intestine plays a role in buffering acidic chyme. MALT contains immune cells, such as lymphocytes and plasma cells, that help protect the intestinal mucosa from pathogens and foreign substances. Additionally, MALT helps regulate the pH of the intestinal contents by neutralizing acidic chyme, which is important for optimal enzymatic activity and absorption in the small intestine.
a) secreting mucus
- Incorrect: The secretion of mucus is primarily the role of goblet cells, which are scattered throughout the epithelium of the small intestine. Mucus serves to lubricate and protect the intestinal epithelium from mechanical damage and chemical irritation.
c) activating pepsin
- Incorrect: Pepsin is an enzyme involved in protein digestion, and its activation primarily occurs in the stomach under acidic conditions. It is produced as pepsinogen by chief cells in the gastric glands and is activated by hydrochloric acid (HCl) secreted by parietal cells.
d) preventing bacteria from entering the bloodstream
- Incorrect: While MALT helps protect the intestinal mucosa from pathogens and foreign substances, its primary role is not to prevent bacteria from entering the bloodstream. Instead, MALT functions in the local immune defense of the mucosal surface of the intestine, including the initiation of immune responses against pathogens encountered in the gastrointestinal tract.
Therefore, the Correct Answer is B.