8. Exocrine Pancreas

Question 1

Describe nerve supply to pancreas
1 Which roots
2 chain
3 Nerve fibre name
4 plexus name

Answer 1

1. T5-9
2. Sympathetic
3. Splanchnic nerves
4. Coeliac or solar plexus

Question 2

Lymph nodes of pancreas (draw pancreas, duodenum, spleen and celiac trunk and label)
There’s 9

Answer 2

Coeliac lymph node
Hepatic lymph node
Pyloric lymph node
Anterior and posterior pancreatico-duodenal lymph node
Superior mesenteric lymph node
Superior and inferior body
Splenic lymph node

Question 3

Blood supply to pancreas

Answer 3

Splenic artery and vein

Posterior to pancreas

Question 4

Draw pancreas and duodenum (and where join); label

Include exocrine and endocrine

Answer 4

Include:
Bile duct
Ampulla of vater/pancreaticoduodenal ampulla
Uncinate process
Auxiliary/accessory duct
Main pancreatic duct
Branch duct

Exocrine pancreas=acinar units and ducts>on branch ducts

Endocrine pancreas=islets of langerhans

Question 5

1. Name 2 buds pancreas forms from
2. 4 main cell types bud cell makes
3. Endocrine=4 types of cells: name & what they secrete
4. Role of each of these 4 main cell types (q2)

Answer 5

1. 2
2. ventral and dorsal
   3a. Endocrine
   Acinar
   Centroacinar
   Ductal
   3b. Endocrine:
   Alpha (glucagon), beta (insulin), gamma (somatostatin>mitogenic), PP cells (pancreatic polypeptide>⬆️aa)
3. Endocrine: secrete hormones
   Acinar: exocrine-secrete digestive enzymes
   Centroacinar cells: pancreatic stem cells
   Ductal cells: secrete bicarb/h2o

Question 6

Main proteases that make up pancreatic enzymes (3)

Answer 6

Elastase
Chymotrypsin
Trypsin

Question 7

Describe secretion/activation of trypsin

Answer 7

Released by acinar cell as trypsinogen
Activated by enterokinase in duodenum
(H+ and activated trypsin also activates trypsinogen; H+ & enterokinase may be involved in same mechanism of activation)

Question 8

CCK

1. acts on
2. causes/effects

Answer 8

1. Acinar cells of pancreas and I cells of small intestine
2. Causes acinar cells to secrete pancreatic ZYMOGENS (inactive enzymes):
   Lipase, amylase and protease zymogens

Question 9

Secretin

1. Acts on
2. Effect
3. How it works (specifics)

Answer 9

1. Duct cells in pancreas
2. HCO3- & H2O secretion, to wash enzymes secreted by acinar cells down
3. A. Secretin receptor on cell
   B. Activates cascade (2nd msger, cAMP, PKA)»activates CFTR channel which moves Cl- outside into lumen
   C. HCO3-/Cl- exchanger moves HCO3- into lumen and Cl- into cell
   D. H2O moves into lumen by osmosis

Question 10

Pathogenesis of pancreatitis in acinar cell

Cause of calcium spike

Answer 10

Ca2+ spike
Spike causes lysosome and zymogen granule to fuse
Lysozyme activates trypsinogen in granule
Activated inside acinar cell>damage >cytokines release>inflammation

Cause of Ca2+ spike: Fatty acid ethyl esters (=ethanol+fatty acid+FAEE synthases)

Question 11

Causes of pancreatitis (5)

Consequences of it (4)

Answer 11

Causes:

1. Increase CCK-PZ (increase CCK activity)
2. Increase trypsinogen
3. Decreasing in trypsinogen inhibitor (SPINK 1/PSTI)
4. Low HCO3-/low ph
5. Low h2o/viscous mucus

Consequences:
Acinar damage
Proteolytic cleavage** of??
Protein plugs
Calcification (some pancreatitis not all)