Topic 54 - The exocrine function of the pancreas, pancreas enzymes, regulation of pancreatic juice secretion

Question 1

Words to include in the exocrine function of the pancreas

Answer 1

• Gastric content
• Neutralize
• Pancreatic juice
• Acinar cells
• Zymogen granules
• Tubules
• HCO₃^- (bicarbonate)
• Interlobular duct
• Extralobular duct
• Main collecting tubule
• Pancreatic duct
• Dudoenum

Question 2

Words to include in pancreas enzymes

Answer 2

• Enzymes
  
  • α-amylase
  • Lipase
  • Esterase
  • Nuclease
• Inactive proenzymes:
  
  • Trypsinogen
  • Chymotrypsinogen
  • Proelastase
  • Procarboxypeptidase
  • Prophospholipase
• Lumen of ileum
• Enteropeptidase
• Trypsin
• Trypsinogen

Question 3

Words to include in regulation of pancreatic juice

Answer 3

• Secretory activity
• Hormoes
• Neurotransmitters
• Parasympathetic
  
  • N. vagus
• Sympathetic
  
  • N. sphlanchnicus
• Cephalic phase
  
  • Protein
  • Juice
• Gastric phase
  
  • Parasympathetic effect
  • Gastrin
  • Enzyme secretion
• Interstitial phase
  
  • Secretin
  • Amino acids
  • Fatty acids
  • Monoglycerides
  • Pancreatic juice secretion
  • CCK

Question 4

Topics to include in the essay

Answer 4

1. The exocrine function of the pancreas
   
   • Role of the function
   • Pancreatic juice
   • Acinar cells
2. Pancreas enzymes
   
   • Enzymes
   • Proenzymes
   • Activation of proenzymes
3. Regulation of pancreatic juice secretion
   
   • Hormones and neurotransmitters
   • Parasymp. and symp.
   • Cephalic phase
   • Gastric phase
   • Interstitial phase

Question 5

The exocrine function of the pancreas

Role of the pancreas

Answer 5

• The exocrine function of the pancreas is producing the pancreatic juice
• It has two main roles:
  
  • Neutralize acidic gastric content getting into the duodenum
  • Secretes enzymes essential for digestion of proteins, fats and carbohydrates

Question 6

The exocrine function of the pancreas

Pancreatic juice secretion

Answer 6

• Exocrine cells of the pancreas is organized into acinar cells, with zymogen granules
• The lumen is narrow, and form drainage tubules
• The drainage tubules produces bicarbonate
• Interlobular ducts are continued as extralobular ducts, which enters the pancreatic ducts that ends in the duodenum
• Ductus interlobularis:
  
  • ​Ions equal with plasma concentration is secreted
• Ductus extralobularis
  
  • HCO₃^- is secreted, influenced by secretion
• Main collecting tubule
  
  • HCO₃^- secretion into lumen increases, Cl^- is taken up

Question 7

Interspecies quantitiy of pancreatic juice secreted

1. Highest
2. Lowest

Answer 7

1. Hightest: horse (6-9.5 l/day)
2. Lowest:
   
   1. Chicken
   2. Dog (0.06-1 l/day)

Question 8

Pancreas enzymes

What does the pancreatic juice contain

Answer 8

• Enzymes:
  
  • α-amylase
  • Lipase
  • Esterase
  • Nuclease
• Inactive proenzymes:
  
  • Trypsinogen
  • Chymotrypsinogen
  • Proelastase
  • Procarboxypeptidase
  • Prophospholipase

Question 9

Where are the proenzymes activated?

Answer 9

• In the lumen of the ileum
• The activation is initiated by enteropeptidase, which produces trypsin (active) from trypsinogen
• Trypsinogen activates other proenzymes to active form

Question 10

Regulation of pancreatic juice

What are secretory activity of ducts and acini regulated by?

Answer 10

Hormones and neurotransmitters

Question 11

Regulation of pancreatic juice

Neural regulation

Answer 11

• Parasympathetic:
  
  • N. vagus cause increased ezymatic secretion
• Sympathetic:
  
  • N. splanchinicus cause decreased amount of pancreatic juice

Question 12

Regulation of pancreatic juice

Regulation in cephalic phase, gastric phase and intestinal phase

Answer 12

1. Cephalic phase
   
   • High protein content
   • Small amount of juice released
2. Gastric phase
   
   • Parasympathetic effect dominates
   • Increased enzyme secretion
3. Intestinal phase
   
   • Influenced by chime in duodenum and jejunum
   • Presence of amino acids, fatty acids or monoglycerides leads to pancreatic juice secretion that is rich in enzymes