liver and pancreas

Question 1

What is the primary blood supply to the liver and GI tract?

Answer 1

Splanchnic circulation

Combined circulation to organs, receiving less than 25% of cardiac output in the post-absorptive stage.

Question 2

What is the composition of pancreatic juice?

Answer 2

Aqueous and enzyme components:
* Aqueous: bicarbonate (HCO3-), Na+, K+, water
* Enzyme: enzymes for digestion of carbohydrates, proteins, and fats

Aqueous component is slightly hypertonic and varies with the rate of secretion.

Question 3

What are the exocrine functions of the pancreas?

Answer 3

Secretes enzyme-rich fluid into the duodenum to complete digestion of:
* Carbohydrates
* Proteins
* Fats

The pancreas is an accessory digestive organ.

Question 4

What are proteolytic enzymes responsible for?

Answer 4

Digestion of protein

Enzymes are classified into endopeptidases and exopeptidases.

Question 5

Why does the pancreas not digest itself?

Answer 5

Pancreatic enzymes are stored as inactive zymogen granules and activated in the duodenum

Activation of trypsinogen occurs in the alkaline environment or via enteropeptidase.

Question 6

What triggers the release of pancreatic exocrine secretions?

Answer 6

Stimuli from:
* CNS (brain)
* Food or fluid in the stomach
* Chyme in the small intestine

Question 7

What are the four major actions of cholecystokinin (CCK)?

Answer 7

• Inhibition of gastric emptying
• Promotion of pancreatic enzyme secretion
• Stimulation of gall bladder contraction
• Trophic effects on exocrine pancreas and gall bladder

Question 8

What is the main function of secretin?

Answer 8

Promotes secretion of bicarbonate and bile to neutralize acidic chyme

Secretin also inhibits gastrin effects.

Question 9

What are the principle actions of gastric inhibitory peptide (GIP)?

Answer 9

• Stimulates insulin secretion
• Inhibits gastric acid secretion
• Slows gastric emptying
• Facilitates fat deposition

Question 10

What is the largest internal organ by mass?

Answer 10

Liver

Accounts for about 2% of body weight.

Question 11

What are the primary functions of the liver?

Answer 11

• Filtering circulation
• Synthesis and secretion of bile
• Metabolism of macronutrients
• Detoxification
• Storage of micronutrients
• Endocrine function

Question 12

What does bile contain?

Answer 12

• Bile salts
• Bile pigments
• Cholesterol
• Phospholipids
• Triglycerides
• Electrolytes

Question 13

Where is bile produced and how is it modified?

Answer 13

Produced by hepatocytes and modified by ductal epithelial cells to increase volume

Bile can be discharged directly into the duodenum or stored in the gall bladder.