Final answer:
Pancreatic zymogens are activated in the duodenum to prevent the pancreas and small intestine from being digested by these powerful enzymes. The process involves enteropeptidase activating trypsinogen to trypsin, which then activates other zymogens, and the presence of intestinal mucus for protection.
Step-by-step explanation:
Activation of pancreatic zymogens occurs in the duodenum. This process protects the pancreas from self-digestion. The pancreas produces protein-digesting enzymes in their inactive forms, known as proenzymes or zymogens, to prevent the inappropriate digestion of the pancreas itself and the small intestine.
Once in the duodenum, an intestinal brush border enzyme called enteropeptidase activates trypsin from trypsinogen, which in turn activates other zymogens such as procarboxypeptidase and chymotrypsinogen into their active forms, carboxypeptidase, and chymotrypsin.
The small intestine is also coated with mucus to protect it from these active enzymes, further ensuring the safety of digestive tissues.