Exocrine Pancreatic Secretion

Question 1

Name the 3 parts of the macroscopic anatomy of the exocrine pancreas

Answer 1

left lobe of pancreas
pancreatic angle
right lobe of pancreas

Question 2

Name the 2 major cell types of the microscopic anatomy of the exocrine pancrase

Answer 2

acinar cells

ductal cells

Question 3

What do acinar cells release?

Answer 3

enzymes

anti-bacterial fluids

Question 4

What do ductal cells release?

Answer 4

fluid

intrinsic factor

Question 5

Explain the islet-acinar axis

Answer 5

islet cells of pancreas perfused first, release hormones into blood
acini perfused next, secrete enzymes into juice b/c of hormone stimulation

Question 6

Name the 4 functions of the exocrine pancreas

Answer 6

neutralization of gastric acid
intrinsic factor secretion
enzymatic digestion of food
anti-bacterial proteins

Question 7

How does the pancreas neutralize gastric acid?

Answer 7

by releasing HCO3-, Cl-, and H20

Question 8

How does the pancreas enzymatically digest food?

Answer 8

by releasing protease, lipase, and amylase

Question 9

What do duct cells release? (2)

Answer 9

HCO3-/fluid

intrinsic factor

Question 10

What do acinar cells release? (2)

Answer 10

enzymes

anti-bacterial proteins

Question 11

What does enterokinase do?

Answer 11

it activates enzymes from their inactive zymogen precursors

Question 12

Explain the cephalic phase of pancreatic secretion

Answer 12

conditioned stimuli cause G cell to secrete gastrin
gastrin stimulates acinar cells in pancreas to secrete enzymes

conditioned stimuli cause parietal cells to release H+
H+ stimulates secretin cells to release secretin
secretin stimulates duct cells in pancreas to release fluid and bicarbonate

Question 13

Explain the gastric/intestinal phases of pancreatic secretion

Answer 13

conditioned stimuli cause parietal cells to release H+
H+ stimulates secretin cells to release secretin
secretin stimulates both duct and acinar cells to release factors

food digestion causes CCK cells to release CCK
CCK stimulates both duct and acinar cells to release factors

Question 14

Name the 4 factors that stimulate enzyme secretion from pancreas

Answer 14

ACh
CCK
GRP
SP

(via calcium, DAG, IP3)

Question 15

Name the 2 factors that stimulate fluid secretion from the pancreas

Answer 15

VIP
secretin

(via cAMP)

Question 16

Where do canines and felines release intrinsic factor?

Answer 16

Canines: gastric and pancreatic
Felines: pancreatic

Question 17

Name the 8 cellular mechanisms by which the pancreas protects itself from auto-digestion

Answer 17

1. E.R. zymogen synthesis
2. vectorial transport from Golgi
3. glycosylation and phosphorylation target enzymes for different compartments
4. lysosomal sequestration
5. zymogen granules
6. pancreatic secretory trypsin inhibitor, which inactivates prematurely activated trypsin
7. endocytosis/export of enzymes
8. distal activation

Question 18

How does trypsin cause pancreatic necrosis?

Answer 18

broad range of proteolytic activity

Question 19

How does elastase cause pancreatic necrosis?

Answer 19

blood vessel elastin digestion
vascular damage
hemorrhage

Question 20

How does lipase and phospholipase A cause pancreatic necrosis?

Answer 20

fat necrosis

membrane dissolution

Question 21

What are the initiating events of acute pancreatitis?

Answer 21

ischemia
inflammation
toxins
infections
drugs

Question 22

What are the acinar events of acute pancreatitis?

Answer 22

blocked secretion
co-localization
enzyme activation
cell injury

Question 23

What are the severity determinants of acute pancreatitis?

Answer 23

inflammatory cytokines
reactive oxygen species
altered redox state
ischemia
apoptosis