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Ch. 23 The Digestive System
Marieb - Human Anatomy & Physiology 7th Edition
Marieb, Hoehn7th EditionHuman Anatomy & PhysiologyISBN: 9780805359091Non è quello che usi tu?Cambia libro di testo
Capitolo 22, Problema 27

Explain why activation of pancreatic enzymes is delayed until they reach the small intestine.

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Understand that pancreatic enzymes are initially secreted in an inactive form called zymogens to prevent them from digesting proteins within the pancreas itself, which could cause tissue damage.
Recognize that these inactive enzymes require activation in the small intestine to become functional and start the digestion process safely.
Identify that the small intestine produces an enzyme called enterokinase (or enteropeptidase), which specifically activates the pancreatic zymogen trypsinogen into trypsin.
Know that trypsin then activates other pancreatic enzymes by converting their inactive forms into active enzymes, ensuring digestion occurs only in the small intestine.
Conclude that this delayed activation mechanism protects the pancreas from autodigestion and ensures enzymes act only where food digestion is needed.

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Pancreatic Enzymes and Their Function

Pancreatic enzymes are digestive proteins produced by the pancreas that break down carbohydrates, proteins, and fats. They are initially secreted in inactive forms called zymogens to prevent self-digestion of the pancreas and surrounding tissues.
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Functions of Enzymes

Zymogen Activation Mechanism

Zymogens are inactive enzyme precursors that require specific biochemical changes to become active. In the small intestine, enzymes like enterokinase convert trypsinogen into trypsin, which then activates other pancreatic enzymes, ensuring digestion occurs only in the intestine.
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02:37
Active Transport

Protection of Pancreatic Tissue

Delaying enzyme activation until reaching the small intestine protects the pancreas from autodigestion and inflammation. If enzymes were activated prematurely within the pancreas, they would digest pancreatic tissue, leading to pancreatitis and tissue damage.
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Pancreas
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