BPK 105 Study Guide - Final Guide: Pancreas, Vagus Nerve, Cholecystokinin

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Module 11 - Review Questions - Part 4
7. Describe the control of release and function of each of the secretions from the
exocrine pancreas. [7 marks]
- The exocrine part of the pancreas is a compound acinar gland.
- The acini produce digestive enzymes.
- The exocrine secretions of the pancreas include bicarbonate ions (HCO3−), which
neutralize the acidic chyme that enters the small intestine from the stomach. The
increased pH resulting from the secretion of HCO3− stops pepsin digestion but provides
the proper environment for the function of pancreatic enzymes.
- Pancreatic enzymes are also present in the exocrine secretions and are important in
digesting all major classes of food (see table 16.1). Without the enzymes produced by
the pancreas, lipids, proteins, and carbohydrates cannot be adequately digested.
- The major proteolytic (protein-digesting) enzymes are trypsin, chymotrypsin, and
carboxypeptidase. These enzymes continue the protein digestion that started in the
stomach, and pancreatic amylase continues the polysaccharide digestion that began in
the oral cavity.
- The pancreatic enzymes also include lipase, a lipid-digesting enzyme, and nucleases,
which are enzymes that degrade DNA and RNA to their component nucleotides.
- The exocrine secretory activity of the pancreas is controlled by both hormonal and neural
mechanisms (figure 16.20; see table 16.2).
- Secretin initiates the release of a watery pancreatic solution that contains a large amount
of HCO3−.
- The primary stimulus for secretin release is the presence of acidic chyme in the
duodenum. Cholecystokinin stimulates the pancreas to release an enzyme-rich solution.
- The primary stimulus for cholecystokinin release is the presence of fatty acids and amino
acids in the duodenum. In turn, enzymes secreted by the pancreas act to digest these
fatty acids and amino acids.
- Parasympathetic stimulation through the vagus nerves also stimulates the secretion of
pancreatic juices rich in pancreatic enzymes. Sympathetic action potentials inhibit
pancreatic secretion.
8. Distinguish between the processes of digestion and absorption through definition and
description. Where in the gastrointestinal system do they generally take place? [4 marks]
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Document Summary

Module 11 - review questions - part 4: describe the control of release and function of each of the secretions from the exocrine pancreas. The exocrine part of the pancreas is a compound acinar gland. The exocrine secretions of the pancreas include bicarbonate ions (hco3 ), which neutralize the acidic chyme that enters the small intestine from the stomach. The increased ph resulting from the secretion of hco3 stops pepsin digestion but provides the proper environment for the function of pancreatic enzymes. Pancreatic enzymes are also present in the exocrine secretions and are important in digesting all major classes of food (see table 16. 1). Without the enzymes produced by the pancreas, lipids, proteins, and carbohydrates cannot be adequately digested. The major proteolytic (protein-digesting) enzymes are trypsin, chymotrypsin, and carboxypeptidase. These enzymes continue the protein digestion that started in the stomach, and pancreatic amylase continues the polysaccharide digestion that began in the oral cavity.

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