Exocrine Pancreatic Secretion Flashcards Preview

Physiology (Gastrointestinal) > Exocrine Pancreatic Secretion > Flashcards

Flashcards in Exocrine Pancreatic Secretion Deck (23):
1

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

left lobe of pancreas
pancreatic angle
right lobe of pancreas

2

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

acinar cells
ductal cells

3

What do acinar cells release?

enzymes
anti-bacterial fluids

4

What do ductal cells release?

fluid
intrinsic factor

5

Explain the islet-acinar axis

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

6

Name the 4 functions of the exocrine pancreas

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

7

How does the pancreas neutralize gastric acid?

by releasing HCO3-, Cl-, and H20

8

How does the pancreas enzymatically digest food?

by releasing protease, lipase, and amylase

9

What do duct cells release? (2)

HCO3-/fluid
intrinsic factor

10

What do acinar cells release? (2)

enzymes
anti-bacterial proteins

11

What does enterokinase do?

it activates enzymes from their inactive zymogen precursors

12

Explain the cephalic phase of pancreatic secretion

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

13

Explain the gastric/intestinal phases of pancreatic secretion

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

14

Name the 4 factors that stimulate enzyme secretion from pancreas

ACh
CCK
GRP
SP

(via calcium, DAG, IP3)

15

Name the 2 factors that stimulate fluid secretion from the pancreas

VIP
secretin

(via cAMP)

16

Where do canines and felines release intrinsic factor?

Canines: gastric and pancreatic
Felines: pancreatic

17

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

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

18

How does trypsin cause pancreatic necrosis?

broad range of proteolytic activity

19

How does elastase cause pancreatic necrosis?

blood vessel elastin digestion
vascular damage
hemorrhage

20

How does lipase and phospholipase A cause pancreatic necrosis?

fat necrosis
membrane dissolution

21

What are the initiating events of acute pancreatitis?

ischemia
inflammation
toxins
infections
drugs

22

What are the acinar events of acute pancreatitis?

blocked secretion
co-localization
enzyme activation
cell injury

23

What are the severity determinants of acute pancreatitis?

inflammatory cytokines
reactive oxygen species
altered redox state
ischemia
apoptosis