The Pancreas and the Liver

Question 1

What is the structure of the pancreas

Answer 1

Retroperitoneal (except tail), close to major blood vessels and difficult to access. It lies in C-shaped curve of duodenum

Question 2

Describe the pancreatic blood supply

Answer 2

It is mainly via the splenic artery from coeliac trunk, as well as the pancreatico-duodenal arteries

Question 3

What are the primary functions of the exocrine pancreas

Answer 3

• Neutralise acid content from stomach
• Deliver enzymes for macronutrient digestion in duodenum

Question 4

What are acinar cells

Answer 4

They are tree like branches and they secrete enzymes and fluid

Question 5

What do duct cells secrete

Answer 5

Bicarbonate

Question 6

Describe bicarbonate secretion

Answer 6

• Secretin and Ach stimulate duct cell secretion
• Cl-/HCO3- exchanger and CFTR chloride channel important for apical secretion of HCO3-

Question 7

What inhibits HCO3- secretion

Answer 7

Substance P

Question 8

Describe the exocrine pancreatic regulation during cephalic phase

Answer 8

• Sight, smell, taste and mastication
• Vagal pathways
• 25% maximum enzyme secretion

Question 9

Describe the exocrine pancreatic regulation during gastric phase

Answer 9

• Distension, gastrin
• Vagal-cholinergic
• 10-20% maximum enzyme secretion

Question 10

Describe the exocrine pancreatic regulation during intestinal phase

Answer 10

• AAs, FAs stimulate I cells in duodenum to release CCK
• Also stimulates a vagovagal enteropancreatic reflex that stimulates acinar cells
• H+ stimulate S cells in duodenum to release secretin
• 50-80% maximum enzyme secretion

Question 11

What effect does cystic fibrosis have on the pancreas

Answer 11

• Progressive pancreatic and pulmonary insufficiency
• Mutations in CFTR gene which codes for cAMP-regulated chloride channel
• Leads to decrease in HCO3- secretion, blockage of ducts and eventual destruction of the pancreas
• Lack of digestive enzymes leads to maldigestion of nutrients

Question 12

What is acute pancreatitis

Answer 12

• Inflammatory condition that may cause local damage to pancreas
• Most common causes are alcohol and gallstones
• Pathogenesis thought to originate in pancreatic acinar cells

Question 13

What is the structure of the liver

Answer 13

The liver has right and left lobes (separated by the falciform ligament), and a quadrate lobe next to the gall bladder. Its posterior surface shows the caudate lobe next to the IVC

Question 14

Describe the blood supply to the liver

Answer 14

• Liver lobule consists of central branch of hepatic vein with triads at six corners
• Triads consist of branches of hepatic artery, portal vein and bile duct

Question 15

How does bile drain

Answer 15

Via canaliculi that lie between hepatocytes that eventually form bile ducts

Question 16

What direction does bile flow compared to blood

Answer 16

Opposite direction

Question 17

What is the peribiliary plexus

Answer 17

It is a network of small veins and lymphatics that surrounds the bile ducts within the liver

Question 18

Where does the peribiliary plexus empty to

Answer 18

Sinusoids by branches of portal vein

Question 19

What are the functions of the liver

Answer 19

• Synthesis and secretion of bile
• Metabolism and storage of carbs, lipids, proteins and vitamins
• Detoxification of metabolic waste
• Synthesis of blood clotting and anticoagulant factors
• Immune system function