Pancreatic exocrine

Question 1

2 main functional structures of pancreas

Answer 1

1. endocrine - islets of langerhan

2. exocrine - acinar and duct cells

Question 2

2 exocrine glands and their products

Answer 2

1. acinar - enzymes

2. duct cells - HCO3

Question 3

reason for HCO3 excretion (2)

Answer 3

1. neutralizes chyme to protect duod

2. optimizes pH for enzymes

Question 4

path for Cl excretion in duct cell

Answer 4

1. stim. by secretin
2. increases cAMP
3. CFTR channel unfolds
4. Cl excreted out
5. Na follows Cl
6. H20 follows Na

Question 5

what is acidic tide

Answer 5

when duct secretes HCO3 into lumen, it puts H+ into blood, which neutralizes HCO3 from stomach

Question 6

what happens in alc. induces pancreatitis

Answer 6

reduced HCO3 and H20 secretion

Question 7

what happens in cystic fibrosis

Answer 7

CFTR mutation means Cl doesn’t leave and no H2O

Question 8

how does this lead to pancreatitis

Answer 8

reduced flow> thickening forms plugs> inflammation and fibrosis> necrosis and atrophy

Question 9

where are enzymes made in acinar cell

Answer 9

ER and stored in vacuoles

Question 10

what controls acinar release

Answer 10

exosytosis is under physiological control, not production

Question 11

what are 3 phase of pnacreatic secretion

Answer 11

1. cephalic - vagus
2. gastric - chemo and mechno recptors
3. intestinal (majority) - hormone and vaso-vagal

Question 12

what are 2 cephalic pathways of panc. secretions

Answer 12

1. direct vagal stim of cells via ACH

2. vagal stim of gastrin> stims panc. cells

Question 13

2 hormones of intestinal phase

Answer 13

1. secretin - release by S cells in response to acid

2. cholecystokinin (CCK) - released by I cells in response to fat and digested proteins

Question 14

what do 2 hormones do

Answer 14

1. secretin - direct stim to make HCO3

2. CCK - indirect stim via vagal to make enzymes

Question 15

path of CCK

Answer 15

fat>I cells make CCK>vagus nerve releases ACH>acinar cells make enzymes>enzymes make trypsin which inhibs CCK

Question 16

path of secretin

Answer 16

acid stims S cells> secrete secreting> ductal cells resnd with HCO3 and H2O

Question 17

in what form are enzymes secreted

Answer 17

zymogens tha are then cleaved to active form to make enzyme

Question 18

how are zymogens activated

Answer 18

1. activating enzymes

2. active form can activate inactive forms

Question 19

names of zymogens

Answer 19

pro____ or _____ogen

Question 20

what happens in abnormal pnacreas

Answer 20

lysozomes and zymogens together to make active form - autodigest

Question 21

3 ways prevent autodigestion

Answer 21

1. separate packages
2. store enzymes as zymogens
3. anti-proteases inside zymogen granules