Lecture 56 "pancreatic & Biliary Function"

Front 1

exocrine secretions from pancreas (2)

Back 1

aqueous juice

enzyme juice

Front 2

endocrine secretions from pancreas (2)

Back 2

glucagon

insulin

Front 3

aqueous juice is secreted by

Back 3

centro-acinar cells

duct cells

Front 4

enzyme juice is secreted by

Back 4

pancreatic acinar cells

Front 5

glucagon is secreted by

Back 5

alpha cells

Front 6

insulin is secreted by

Back 6

beta cells

Front 7

functions of aqueous juice (2)

Back 7

(1) neutralizes acidic chyme from stomach

-allows pancreatic enzymes to function in their optimal neutral range

- prevents damage to duodenal mucosa by gastric acid

- inactivates pepsin

(2) dilutes enzyme juice

Front 8

Secretion rate (slow and fast) vs. composition of aqueous secretion

[Na]
[HCO3]
[Cl]
[K]

Back 8

[Na] high at both slow and fast secretion rates

[HCO3] low at slow secretion rates and high at fast secretion rates*

[Cl] high at slow secretion rates and low at fast secretion rates*

[K] low at both slow and fast secretion rates

* HCO3/Cl exchanger function is higher at slow secretion rates

Front 9

CFTR (cystic fibrosis transmembrane regulator) chloride channel is activated by

Back 9

secretin

Front 10

secretin secretion is stimulated by the presence of

Back 10

gastric acid (acidic chyme)

Front 11

secretin action is enhanced by the presence of

Back 11

CCK

Front 12

secretin inhibits _____ secretion in the stomach, but stimulates _______ secretion in stomach and pancreatic aqueous secretion

Back 12

gastric acid

pepsinogen

Front 13

upon presence of fatty acids in the duodenum, ______ is released into the blood

Back 13

CCK

Front 14

cystic firbosis is due to

Back 14

blocked or defective CFTR chloride channel

Front 15

patients with cystic fibrosis have viscous ______ and _______

Back 15

pancreatic aqueous secretion

pulmonary mucous

Front 16

pancreatic enzymes are synthesized by ______ cells

Back 16

pancreatic acinar cells

Front 17

pancreatic enzyme secretion composition:

*protein digestion
*lipid/phospholipid digestion
*polysaccharide digestion
*nucleotide digestion

Back 17

trypsinogen
chymotrypsinogen
procarboxypeptidase A
procarboyxpeptidase B

lipase
phospholipase

amylase

ribonuclease
deoxyribonuclease

Front 18

trypsinogen is activated by (2)

Back 18

enterokinase

trypsin

Front 19

chymotrypsinogen is activated by

Back 19

trypsin

Front 20

procarboxypeptidase A and procarboxypeptidase B are activated by

Back 20

trypsin

Front 21

lipase is actiaved by

Back 21

bile salts

Front 22

phospholipase is actiaved by

Back 22

bile salts

Front 23

amylase is activated by

Back 23

Cl

Front 24

during the gastric phase, pancreatic enzyme secretion is stimulated by

Back 24

gastrin

Front 25

during the intestinal phase, pancreatic enzyme secretion is stimulated by (2)

Back 25

secretin (acidic chyme)

CCK (fat)

Front 26

secretin is synthesized by

*cell type
*location

Back 26

S cells

duodenal muscosa

Front 27

secretin secretion is stimulated by presence of _____ in the duodenum

Back 27

gastric acid (acidic chyme)

Front 28

pancreatic aqueous secretion is synthesized by

Back 28

intestinal duct cells

Front 29

characteristics of pancreatic aqueous secretion:

*volume
*[HCO3]
*[enzyme]

Back 29

*volume: high
*[HCO3]: high (neutralizes gastric acid in the duodenum)
*[enzyme]: low

Front 30

secretin inhibits secretion of _____ and release of _____

Back 30

gastric acid

gastrin

Front 31

secretin stimulates secretion of

Back 31

pepsinogen

Front 32

CCK is synthesized by

*cell type
*location

Back 32

I cells

duodenal mucosa

Front 33

CCK secretion is stimulated by presence of ______ or _____ in the duodenum

Back 33

fatty acids

amino acids

Front 34

CCK stimulates ______ and _____ secretion

Back 34

pancreatic aqueous

pancreatic enzyme (pancreatic acinar cells)

Front 35

contraction of the gallbladder and relaxation of the sphincter of Oddi is stimulated by

Back 35

CCK

Front 36

pancreatic enzyme secretion:

*volume
*[enzyme]

Back 36

*volume: low
*[enzyme]: high

Front 37

pancreatic enzyme secretion is stimulated by (5)

*Ca mediated
*cAMP mediated

Back 37

*Ca mediated:
- CCK
- ACh
- gastrin

*cAMP mediated:
- secretin
- VIP (important when vipomas are present)

*secretin and CCK act synergistically*

Front 38

function of bile salts

Back 38

emulsify fats and steroids in the intestine

Front 39

bile is produced and secreted by the

Back 39

liver

Front 40

path of bile once it's synthesized by the liver

Back 40

bile canaliculi --> bile ducts --> hepatic ducts --> common bile duct --> duodenum

bile canaliculi --> bile ducts --> hepatic ducts --> cystic duct --> gallbladder

Front 41

types of bile secretion (2)

Back 41

bile acid independent secretion

bile acid dependent secretion (bile acid serves as a negative feedback mechanism to bile secretion)

Front 42

bile acid independent secretion

*location (2)
*stimulated by

Back 42

canaliculi and bile ducts

secretin

Front 43

bile acid dependent secretion

*location
*inhibited by

Back 43

parenchymal cells

bile acids returning to liver in portal blood

Front 44

bile acid synthesis is inhibited by

Back 44

bile acids returning to the liver (negative feedback inhibition)

Front 45

bile salts are conjugated with (2)

Back 45

glycine (75%)

taurine (25%)

Front 46

conjugated bile salts:

*pK
*charge at neutral pH
*water soluble?
*amphipathic?

Back 46

*pK: 4
*charge at neutral pH: negative (anionic: -OH and COO- groups)
*water soluble at neutral pH?: Yes
*amphipathic at neutral pH?: yes (allows bile salts to emulsify and solubilize fats and steroids)

Front 47

bile salts are deconjugated and dehyodroxylated by

Back 47

intestinal bacteria (distal ileum)

Front 48

non-ionic bile acids are absorbed in the

Back 48

small intestine

Front 49

concentration of bile in the gallbladder is due to

Back 49

active transport of Na, Cl, and HCO3 out of the lateral membrances of gallbladder epithelial cells

Front 50

relative bile concentration:

liver vs. gallbladder

Back 50

bile is 10X more concentrated in the gallbladder than in the liver (due to salt and water removal)

Front 51

when concentrated, bile forms

Back 51

micelles

Front 52

bile micelles are composed of (3)

Back 52

bile salts (80%)

lecithin (15%)

cholesterol (5%)

Front 53

osmotic activity:

bile micelles vs. bile micelle components

Back 53

bile micelles have less osmotic activity than individual bile micelle components

Front 54

release of bile from the gallbladder is stimulated by (2)

Back 54

CCK

vagus n.

Front 55

gallstone formation:

*stages (3)
*location

Back 55

*supersaturation of cholesterol
- occurs in the liver

*nucleation and precipitation (seeding of cholesterol cyrstals or microstones)
- occurs in the gallbladder

*growth of microstones to form macrostones